DigitalUM :: Browsing by Subject "Collagen"

Browsing by Subject "Collagen"

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Open Access
A comparative study of extracellular matrix remodeling in two murine models of emphysema
(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2013) Lopes, F.D.T.Q.S.; Toledo, A.C.; Olivo, C.R.; Prado, C.M.; Leick, E.A.; Medeiros, M.C.; Santos, A.B.G.; Garippo, A.; Martins, M.A.; Mauad, T.
A single instillation of porcine pancreatic elastase (PPE) results in significant airspace enlargement on the 28th day after instillation, whereas cigarette smoke (CS) exposure requires 6 months to produce mild emphysema in rodents. Considering that there are differences in the pathogenesis of parenchymal destruction in these different experimental models, it is likely that there may be different patterns of extracellular matrix (ECM) remodeling. To evaluate ECM remodeling, C57BL/6 mice were submitted to either a nasal drop of PPE (PPE 28 Days) or exposed for 6 months to cigarette smoke (CS 6 months). Control groups received either an intranasal instillation of saline solution (Saline 28 Days) or remained without any smoke inhalation for six months (Control 6 months). We measured the mean linear intercept and the volume proportion of collagen type I, collagen type III, elastin and fibrillin. We used emission-scanning confocal microscopy to verify the fiber distribution. Both models induced increased mean linear intercept in relation to the respective controls, being larger in the elastase model in relation to the CS model. In the CS model, emphysema was associated with an increase in the volume proportion of fibrillin, whereas in the PPE model there was an increase in the parenchymal elastin content. In both models, there was an increase in collagen type III, which was higher in the CS-exposed mice. We concluded that ECM remodeling is different in the two most used experimental models of emphysema.
Open Access
Abnormal collagen deposition in synovia after collagen type V immunization in rabbits
(Murcia : F. Hernández, 2008) Tsuzuki Ichicawa Ogido, Luciana; Walcy Rosolia, Teodoro; Pereira Velosa, Ana Paula; De Oliveira, Cristiane Carla; Roger Parra, Edwin; Capelozzi, Vera Luiza; Hajime Yoshinari, Natalino
Sinovitis in Scleroderma (SSc) is rare, usually aggressive and fully resembles rheumatoid arthritis. Experimental models of SSc have been used in an attempt to understand its pathogenesis. Previous studies done in our laboratory had already revealed the presence of a synovial remodeling process in rabbits immunized with collagen V. To validate the importance of collagen type V and to explore the quantitative relationship between this factor and synovia remodeling as well as the relationship between collagen type V and other collagens, we studied the synovial tissue in immunized rabbits. Rabbits (N=10) were immunized with collagen V plus Freund’s adjuvant and compared with animals inoculated with adjuvant only (N=10). Synovial tissues were submitted to histological analysis, immunolocalization to collagen I, III and V and biochemical analysis by eletrophoresis, immunoblot and densitometric method. The synovial tissue presented an intense remodeling process with deposits of collagen types I, III and V after 75 and 120 days of immunization, mainly distributed around the vessels and interstitium of synovial extracellular matrix. Densitometric analysis confirmed the increased synthesis of collagen I, III and V chains (407.69±80.31; 24.46±2.58; 70.51±7.66, respectively) in immunized rabbits when compared with animals from control group (164.91±15.67; 12.89±1.05; 32±3.57) (p<0.0001). We conclude that synovial remodeling observed in the experimental model can reflect the articular compromise present in patients with scleroderma. Certainly, this experimental model induced by collagen V immunization will bring new insights in to pathogenic mechanisms and allow the testing of new therapeutic strategies to ameliorate the prognosis for scleroderma patients.
Open Access
Abnormal elastin and collagen deposition is present in extracranial arteriovenous malformations: A comparison to intracranial disease
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2019) Wei, Ting; Shalin, Sara; Draper, Elizabeth; Miller, Emily; Zhang, Haihong; Sun, Ravi; Lee, Madison; Albert, Gregory; Richter, Gresham T.
Background. Vascular malformations are characterized by anomalous vascular channels with fragile walls and a propensity to bleed. Arteriovenous malformations (AVMs) in particular have disorganized vascular spaces with intervening fibrosis. Characterization of the structural abnormalities of these vessels has not been comprehensively evaluated. We hypothesize that AVMs are likely to demonstrate altered elastic and collagen fiber organization and distribution, reflecting their fragility, vascular instability, and abnormal development. Methods. Fifteen AVMs were histologically evaluated by H&E, elastin and trichrome staining. To identify potential differences between extracranial and intracranial AVMs, 5 AVMs were harvested from the brain (n=5) and 10 from extracranial sites involving the skin and deep soft tissue (n=10). Results. The elastin staining demonstrated reduplication, fragmentation and disruption of internal elastic lamina as well as irregular thickness, and inconsistent vascular density of all AVM specimens. Trichrome staining revealed thickening of the intimal layers of AVM arteries and demonstrated an irregular thickness of venous walls within the malformation and some areas of medial degeneration. Intracranial AVMs are characterized by more intramural inflammation with predominant neutrophil and lymphocyte infiltration. In contrast, extracranial AVMs display more extravascular inflammation with mast cell and neutrophil infiltration. Microvascular proliferations intervening between larger blood vessels were also noted in both types of AVMs, but more obvious in extracranial AVMs. Conclusion. These observed histologic anomalies of AVMs demonstrate disorganized deposition of elastin and collagen that point to the clinically observed vascular instability and fragility of these lesions
Open Access
An ultratructural and immunohistochemical study of extracellular matrix in meningiomas
(Murcia : F. Hernández, 1990) Hisashi Nitta; Tetsumori Yamashima; Junkoh Yamashita; Toshihiko Kubota
Extracellular matrix of meningiomas was studied by light and electron microscopy with the aid of immunohistochemical techniques. Special attention was paid to the distribution of type 1,111, IV, V collagens and laminin with a comparison between meningothelial and fibroblastic types. Connective tissue fibers and basement membrane were not found among the tumor cells in the meningothelial type, but were found in the fibroblastic type. The immunolocalizations were consistently demonstrated extracellularly, but were not within the cytoplasm. Type 1, 111 and V collagens were usually demonstrated in the fibrous septum in the meningothelial type, while they were localized among the tumor cells in the fibroblastic type. Furthermore, type IV collagen and laminin were demonstrated within the vascular walls or around the syncytium in the meningothelial type, while they were localized among the tumor cells in the fibroblastic type. In both types the expression of type IV collagen and laminin was closely related to the distribution of basement membrane. Although meningothelial and fibroblastic meningiomas showed quite different distribution of extracellular matrices, the profile of collagen types expressed by these two basic types was essentially the same. The cellular derivation of meningiomas was discussed with particular attention to the structure of human arachnoid villi and meninges.
Open Access
Cellular proliferation, differentiation and apoptosis in polyether-polyurethane sponge implant model in mice
(Murcia : F. Hernández, 2006) Campos, Paula P.; Andrade, Silvia P.; Moro, L.; Ferreira, M.A.N.D.; Vasconcelos, A.C.
The integration of implanted material to host organism requires spatial and temporal organization of several cellular processes, such as proliferation, differentiation and apoptosis. Despite the clinical relevance of these processes, there is little information regarding the sequence of such events in synthetic matrices. Here, we present a combination of techniques used to characterize the fibrovascular response in subcutaneous polyether-polyurethane sponge implants in mice at days 4, 7, 10 and 14 postimplantation. The AgNOR technique was modified and used as a surrogate marker for proliferating and activated cells invading the implant. The number of AgNOR-stained cells increased progressively from day 4 (606±76) to day 14 (2146±71) postimplantation. The number of TUNEL-positive (apoptotic index) cells also increased progressively from day 4 (459±40) to day 14 (1157±119) postimplantation. However, the ratio of TUNEL-labeled/proliferating cells had its highest peak in the early phase of the process remaining stable until day 14. Using Picrosirius staining it was shown that thin collagen increased from day 4, peaking at day 10 and falling markedly at day 14, whereas dense collagen increased progressively during the whole period. These experiments hold potential to investigate not only distinct phases of tissue repair induced by synthetic matrices but also to study underlying mechanisms involved
Open Access
Differences in collagen distribution of healthy and regenerated periodontium. Histomorphometric study in dogs
(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2013) Souza, Sérgio Luis Scombatti de; Macedo, Guilherme O.; Silveira e Souza, Adriana M.M.; Taba Jr, Mário; Novaes Jr, Arthur B.; Oliver, Constance; Jamur, Maria C.; Correa, Vani M.A.
Previous studies have shown that there is a relationship between periodontal disease and the distribution of collagen fibers. This study evaluated the distribution of collagen types I and III in regenerated bone and periodontal ligament, comparing them to the tissues near the regenerated area and to the healthy periodontium. In the third (P3) and fourth (P4) mandibular premolars of 5 healthy mongrel dogs, bilaterally, buccal class 2 furcation lesions were surgically created and chronified for 3 weeks. After that, full flaps were elevated and expanded polytetrafluoroethylene (e-PTFE) membranes were adapted, sutured and recovered by the flaps. Two weeks after surgery, two membranes on the same side were removed and the other membranes were removed four weeks after surgery. The dogs were euthanized at 12 weeks following placement of the e-PTFE membranes. P3 and P4 teeth as well as the second premolars (healthy control teeth) and their periodontal tissues were removed and histologically processed for Collagen Quantification (COLQ). The amount of type III collagen was higher in native bone compared to the regenerated area. For periodontal ligament, COLQ for type I collagen showed statistically significant differences (Tukeys’s Multiple Comparison, p<0.05) between the regenerated groups and the control group. These differences were not found for type III COLQ. There are significant differences in collagen distribution among the regenerated, native and control tissues. Membrane removal 2 or 4 weeks postoperatively did not influence the collagen composition.
Open Access
Effect of rehabilitation protocols on muscle function and morphology following hindlimb disuse in weanling rats
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Leite Nogut, Keite i; Bianchi, Eduardo; Chesca Simões, Deise Lúcia; Mattiello-Sverzut, Ana Claudia; de Moura-Jucá, Renata Viana Brígido
Background: Primary or secondary disorders in developing skeletal muscles are prevalent in physical therapy practice. Assessment of gait functional changes and morphological aspects of hindlimb muscles of weanling rats have not been reported simultaneously in the literature. Rehabilitation by active (eccentric training) and passive (stretching) exercises after hypomobility needs to be investigated. Methods: After ten days of immobilisation in a plantar flexion-shortened position, animals underwent eccentric training on treadmills, intermittent (a single series of ten exercises of 30 seconds each, with a 30-s interval) or continuous stretching protocols for 40 minutes, or had free cage activity for three days. Analysis of gait variables and muscle morphology (immunohistochemical staining of soleus and plantar muscles for fibronectin and types I and III collagen and immunofluorescence staining for dystrophin, laminin, Pax-7, and CD68) were performed. Results: On the third day, the rehabilitated animals touched the ground surface with their toes, except for the group undergoing continuous stretching. The total amount of extracellular macrophages was higher in the rehabilitated animals. The number of satellite cells was not significantly different between groups. Conclusion: Three days of active training (eccentric exercise) showed greater effectiveness compared to the other rehabilitation programs. Weanling rats seem to respond differently to external stimuli such as disuse and remobilisation.
Open Access
Halofuginone and muscular dystrophy
(Murcia: F. Hernández, 2011) Pines, Mark; Halevy, Orna
Muscular dystrophies (MDs) include different inherited diseases that all result in progressive muscle degeneration, impaired locomotion and often premature death. The major focus of MD research has been on alleviating the primary genetic deficit - using gene therapy and myoblast-transfer approaches to promote expression of the deficient or mutated genes in the muscle fibers. Although promising, these approaches have not yet entered into clinical practice and unfortunately for MD patients, there is currently no cure. Thus, the development of complementary and supportive therapies that slow disease progression and improve patients' quality of life is critically important. The main features of MDs are sarcolemmal instability and increased myofiber vulnerability to mechanical stress, resulting in myofiber degeneration. Fibrosis, with progressive replacement of muscle tissue, is a prominent feature in some MDs, preventing complete regeneration and hampering muscle functions. TGFß is the leading candidate for activating fibroblasts and eliciting overproduction of extracellular matrix (ECM) proteins. Halofuginone, an inhibitor of Smad3 phosphorylation downstream of TGFß signaling, inhibits the activation of fibroblasts and their ability to synthesize ECM, regardless of their origin or location. In animal models of MDs with prominent muscle fibrosis, halofuginone treatment has resulted in both prevention of collagen production in young animals and resolution of established fibrosis in older ones: the reduction in muscle collagen content was associated with improved muscle histopathology and major improvements in muscle function. Recently, these halofuginonedependent improvements were also observed in MD with minor fibrosis involvement, probably due to a direct effect of halofuginone on muscle cells, resulting in myotube fusion that is dependent on Akt and MAPK pathway activation. In summary, halofuginone improves muscle histopathology and muscle functions in various MDs, via inhibition of muscle fibrosis on the one hand, and increased myotube fusion on the other.
Open Access
Histochemical study of the blue autofluorescence of collagen in oral irritation fibroma: Effects of age of patients and of the duration of lesions
(Murcia : F. Hernández, 1994) Dayan, D.; Wolman, M.; Hammel, I.
The intensity of the autofluorescence of collagen was measured in 27 irritation fibromata of the buccal mucosa and 13 of the lip. The intensity of fluorescence correlated positively with the duration of the lesion. The fluorescence intensity also increased with the patients' age. The present observations show that in irritation fibromata of buccal and lip mucosae, the intensity of blue autofluorescence of the collagen increases with duration of the lesions and with the age of patients.
Open Access
Histological scoring of articular cartilage alone provides an incomplete picture of osteoarthritic disease progression
(Murcia : F. Hernández, 2010) Barley, R.D.C.; Bagnal, K.M.; Jomha, N.M.
Purpose: To ascertain whether molecularsubcategories of disease progression exist withinestablished histological grades of articular cartilage(AC). Methods: Based on H&E and safranin-O stainingof AC sections obtained from 18 knee arthroplastysurgeries, 30 samples ranging from Mankin ScoringSystem grade 1 through 5 were identified. Immuno-histochemical (IHC) analysis for collagen type II andaggrecan was performed on serial sections of theparaffin-embedded AC samples. Six AC samples fromeach of the five Mankin Scoring System grades wereexamined. Results: Significant IHC differences incollagen type II and aggrecan deposition were seenwithin AC samples from all five histological grades. Therange of IHC differences in collagen type II andaggrecan increased with increasing histological grade. Achange in the pattern of collagen type II deposition wasobserved in MG-3 AC that was consistent with a switchin collagen type II metabolism. Conclusions: IHCstaining of collagen type II and aggrecan can identifydifferences within histological grades of AC that areconsistent with the existence of molecular subcategories.These differences were detectable even within the lowesthistological grades; therefore the use of IHC staining canfurther enhance and refine the scoring of ACdeterioration in early osteoarthritis (OA). Furthermore,the changes seen in the deposition pattern for bothaggrecan and collagen type II suggest that they could beused to monitor key molecular events in OAprogression. These findings also underscore the need forthe development of IHC scoring criteria.
Open Access
Influence of a hypercholesterolemic diet on the collagen composition of the bladder wall extracellular matrix in rats
(F. Hernandez y JuanF. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología., 2012) Nunes, R.L.V.; Bruschini, H.; Utsunomia, K.; Silveira, M.A.; Teodoro, W.R.; Leite, K.R.M.; Srougi, M.
Purpose: To investigate the effects of hypercholesterolemic diet on the collagen composition of urinary bladder wall. Materials and methods: Forty-five female 4-week-old Wistar rats were divided into three groups: 1) control group fed a normal diet (ND); 2) model of bladder outlet obstruction (BOO) group fed a ND; and 3) group fed a HCD (1.25% cholesterol). Total serum cholesterol, LDL cholesterol and body weight were assessed at baseline. Four weeks later, group 2 underwent a surgical procedure resulting in a partial BOO, while groups 1 and 3 underwent a sham similar surgical procedure. Six weeks later, all animals had their bladders removed; serum cholesterol and LDL cholesterol levels and body weights were measured. Morphological and morphometric analysis was performed by Picrosirius staining and collagen types I and III were identified by immunofluorescence. Statistical analysis was completed and significance was considered when p<0.05. Results: Rats fed an HCD exhibited a significant increase in LDL cholesterol levels (p<0.001) and body weight (p=0.017), when compared to the groups fed a ND during the ten-week study period. Moreover, the HCD induced morphological alterations of the bladder wall collagen, regarding thin collagen fibers and the amounts of type III collagen when compared to the control group (p=0.002 and p=0.016, respectively), resembling the process promoted in the BOO model. Conclusions: A hyper-cholesterolemic diet in Wistar rats promoted morphological changes of the bladder types of collagen, as well as increases in body weight and LDL cholesterol.
Open Access
Matrix metalloproteinase-1 (MMP-1) and (MMP-8) gene polymorphisms promote increase and remodeling of the collagen III and V in posterior tibial tendinopathy
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Diniz Fernandes, Tulio; Godoy Santos, Alexandre Leme; Santos, Maria Cristina; Pontin, Pedro; Alves Pereira, Caio Augusto; Justi Jardim, Yuri; Pereira Velosa, Ana Paula; Maffulli, Nicola; Teodoro, Walcy Rosolia; Capelozzi, Vera Luiza
Posterior tibial tendinopathy (PTT) can lead to acquired flatfoot in adults. Many patients develop PTT without any identifiable risk factors. Molecular changes in extracellular matrix (ECM) and matrix metalloproteinase (MMP) polymorphism may influence the risk of developing PTT. We aim to investigate the association between matrix metalloproteinase-1 (MMP1) and (MMP-8) gene polymorphisms with changes in collagen I, III and V in PTT. A case-control study with 22 patients and 5 controls was performed. The MMP-1 (2G/2G) and MMP-8 (T/T) genotypes were determined by PCR-restriction fragment length polymorphism. Tendon specimens were evaluated by a histologic semiquantitative score, immunofluorescence and histomorphometry for collagen I, III and V. Tendon specimens from PTT demonstrated marked distortion of the architecture with necrosis, large basophilic areas with disruption of the normal linear orientation of collagen bundles, infiltration of inflammatory cells, dystrophic calcification and ossification. Under immunofluorescence, PTT tendon specimens showed weak green fluorescence and diffuse distribution of collagen I fibers, but strong fluorescence of collagen III and V. The collagen I fibers were significantly decreased whereas an increase of collagen III and V were found in PTT compared to control groups. In addition, PTT group presented a significant association with MMP-1 and MMP-8 gene polymorphisms. Patients with PTT matrix metalloproteinase-1 (MMP-1) and (MMP-8) gene polymorphisms presented an increase of the collagen III and V ratio, suggesting that the higher proportion in degenerated tendons could contribute to a decrease in the mechanical resistance of the tissue. Still, functional and association studies are needed to elucidate evident roles of MMPs in PTT.
Open Access
Morphological and histomorphometric evaluation of the ventral rectus sheath of the rectus abdominis muscle, fascia lata and pectoral fascia. The beginning of a morphological information bank of human fascias
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2017) Morales Avalos, Rodolfo; Soto Domínguez, Adolfo; García Juárez, Jaime; Cardenas Serna, Marcela; Esparza Hernández, Claudia N.; Carreño Salcedo, Sofía Alejandra; Montes de Oca Luna, Roberto; Loera Arias, María de Jesús; Saucedo Cárdenas, Odila; Elizondo Omaña, Rodrigo E.; Guzmán López, Santos
The aim of this study was to characterize and compare the morphological and histomorphometric characteristics of the pectoral fascia, fascia lata and ventral rectus sheath. Twenty cadaveric samples of these fascias were analyzed and stained with hematoxylin and eosin, orcein, Van Gieson, Masson’s trichrome and Verhoeff’s stain (1200 slides in total). Morphological evaluation, semiquantitative, morphometric and microdensitometric analysis of elastic fibers present in each of the tissues and a morphometrical analysis of tissue thickness were performed. The mean value of the pectoral fascia thickness was 612±68.13 µm; 84±246 µm for the fascia lata and 584±92 µm for the ventral rectus sheath. The area occupied by the elastic fibers in the pectoral fascia was 12.24±5.84%; 6.54±3.85% for the fascia lata and 11.11±5.26% for the ventral rectus sheath. There were no statistically significant differences when comparing the mean values between the pectoral fascia and the ventral rectus sheath (p=0.07). There were statistically significant differences when comparing the fascia lata to the pectoral fascia and the ventral rectus sheath (p≤0,001). This study reports other morphological characteristics not described in previous histological studies of the analyzed tissues. The results of the morphometric and densitometric analysis in this study reveal that the fascia lata has the fewest elastic fibers of all the tissues analyzed, and the pectoral fascia has the most. These results will be useful for the beginning of a morphological information bank of human fascias.
Open Access
Morphological changes during the formation of amoebic liver abscess in vagotomized hamsters.
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Sánchez Alemán, Esperanza; Lili Carrillo, Leticia María; Muñoz Ortega, Martin Humberto; Martínez Saldaña, Ma. Consolación; Ventura Juárez, Javier
Amoebic liver abscess (ALA) is the main extra-intestinal complication caused by Entamoeba histolytica. Given the histological features of ALA in hamsters and the importance of the vagus nerve in the immune response, the aim of this study was to identify and analyze the major changes in ALA that are caused by a vagotomy. The changes found are related to inflammatory foci and abscess size, the type of collagen formed, and the number of trophozoites in lesions. Male hamsters were divided into three groups: Intact animals (IA) and those undergoing a false operation (SHAM) or a subdiaphragmatic vagotomy (VAG). In each group, E. histolytica trophozoites or culture medium (CM) were inoculated in hamsters by the intrahepatic route, and then euthanized at 6h, 12h, 24h, 48h, 4d or 7d post- infection. Initially the growth of the abscess was more rapid in the VAG group, but at day 7 it was faster in the IA and SHAM groups. VAG animals showed a higher quantity of type III collagen than the IA and SHAM groups. A larger number of amoebic trophozoites/mm 2 was observed up to day 4 in VAG hamsters (23.3±2.19) compared to IA (14.6±0.23) and SHAM (6.13±0.87) animals. This parameter decreased by day 7 in VAG (13.4±0.87) with respect to IA (24.7±1.47) and SHAM (21.7±1.48). The results show that a subdiaphragmatic vagotomy influenced the development of ALA in hamsters, suggesting a modification of the morphological structure of damaged hepatic tissue.
Open Access
Oxidative stress, isoprostanes and hepatic fibrosis
(Murcia : F. Hernández, 2009) Comporti, Mario; Arezzini, Beatrice; Signorini, Cinzia; Vecchio, Daniela; Gardi, Concetta
An introduction to oxidative stress enlightening the spreading of interest in lipid peroxidation in the 60's and in the identification of cytotoxic aldehydes originating from it is given. The discovery of F2 -isoprostanes as specific markers of oxidative stress is described. Isoprostanes are also agonists of important biological effects. Since a relationship between oxidative stress and collagen hyperproduction has been previously suggested, and since lipid peroxidation products (aldehydes) have been proposed as possible mediators of liver fibrosis, we investigated whether collagen synthesis is induced by F2 -isoprostanes, which can posses receptors for signal transduction pathways. In a rat model of carbon tetrachloride-induced hepatic fibrosis, plasma isoprostanes were markedly elevated for the entire experimental period and hepatic collagen content was also increased. Moreover, when hepatic stellate cells (HSC) isolated from normal livers were cultured up to activation and then treated with F2 -isoprostanes (8-epiPGF2α ) in the concentration range found in the in vivo studies (10-9 to 10-8 M), a striking increase in DNA synthesis, in cell proliferation and in collagen synthesis was observed. F2 -isoprostanes also increased the production of transforming growth factor-ß1 by U937 cells, assumed as a model of Kupffer cells or liver macrophages. The hypothesis that F2 -isoprostanes generated by lipid peroxidation in hepatocytes mediate HSC proliferation and collagen hyperproduction, seen in this experimental hepatic fibrosis, was reinforced by the demonstration, by using immunoblot analysis, that isoprostane receptors identical or analogous to those for thromboxane A2 (TxA2 r) are present in HSC. Immunocytochemical studies showed the major localization of TxA2 r in the perinuclear site and its colocalization with α-smooth muscle actin.
Open Access
Polarization microscopy of picrosirius red stained sections. A useful method for qualitative evaluation of intestinal wall collagen
(Murcia : F. Hernández, 1994) Rabau, M. Y.; Dayan, D.
Collagen pattern in healing anastomosis of intestinal wall was compared with its normal pattern in the submucosal layer. Polarization colours were recorded for thin (0.8 pm or less) and thick (1.6-2.4 pm) collagen fibres. The polarization colours of thick collagen fibres in the anastomotic site were more greenish-yellow and yellow than those in normal intestine which were more yellowish-orange and orange. These findings indicate that the collagen in the anastomotic site 4 days after operation is less packed than the collagen of normal rat intestine. Examination of the polarization colours of Picrosirius red-stained sections is a useful procedure to follow healing of anastomotic sites or diagnosis of collagen pathology in different pathologic conditions in the intestinal wall.
Open Access
Quantitative structural organization of the sclera in chicks after deprivation myopia measured with second harmonic generation microscopy
(Frontiers Media, 2024-10-22) Bueno García, Juan Manuel; Martínez-Ojeda, Rosa M.; Fernández, Enrique J.; Feldkaemper, Marita; Física
Visual deprivation causes enhanced eye growth and the development of myopia, which is associated with a change in the arrangement of collagen fibers within the sclera. A second harmonic generation (SHG) microscope has been used to image the collagen fibers of unstained scleral punches from the posterior part of chicken eyes. We aimed to analyze the fibrous scleral tissue and quantify the changes in collagen organization in relation to the extent of induced deprivation myopia. The scleral architecture was assessed with the Radon transform (RT) through the parameter called structural dispersion (SD) that provides an objective tool to quantify the level of organization of the collagen network. We found that final refraction and axial length changes were linearly correlated. However, no significant differences in scleral thickness were found for different amounts of induced myopia. In contrast, a significant correlation between SD and refraction was demonstrated, ranging from a non-organized (in the control sclerae) to a quasi-aligned distribution (with a dominant direction of the fibers, in the sclera of myopic chicks). These findings demonstrate a remodeling process of the scleral collagen associated with myopia progression that can be measured accurately combining SHG imaging microscopy and RT algorithms.
Open Access
Radiofrequency preserves histoarchitecture and enhances collagen synthesis in experimental tendon injury
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Akamatsu, Flavia Emi; Saleh, Samir Omar; Hojaij, Flávio; Real Martinez, Carlos Augusto; Andrade, Mauro; Teodoro, Walcy Rosolia; Jacomo, Alfredo Luiz
We investigated the action of radiofrequency (RF) on the healing process after inducing experimental lesions of the Achilles tendon in rats. Wistar rats were surgically subjected to bilateral partial transverse sectioning of the Achilles tendon. The right tendon was treated with radiofrequency (RFT), whereas the left tendon served as a control (CT). On the third postoperative day, the rats were divided into three experimental groups consisting of ten rats each, which were treated with monopolar radiofrequency (Tonederm™) until they were sacrificed on the 7th, 14th or 28th days. The histological specimens were studied for inflammatory cell content, collagen types I and III, immunostaining and morphometry. Total collagen were biochemically analyzed and to evalute fibroblast and myofibroblast proliferation by vimentin and α-actin smooth muscle immunohistochemistry methods. Statistical analysis was performed using the Student's ttest, the sign test and the Kruskal-Wallis test to compare tendons treated with radiofrequency with the non-treated tendons (α=5%; α=10%). Larger amounts of collagen I with hydroxyproline content and myofibroblast cells were clearly evident within 7 days (p<0.05). No difference was observed in the inflammatory cell content between the groups. We found better collagen arrangement with RF administration across the entire time studied. Radiofrequency administration preserves histoarchitecture and enhances collagen synthesis during the initial phases of cicatrization, suggesting that the treatment can provide improved stiffness during the most vulnerable phases of tendon healing. Clinical studies may include RF among the therapeutic tools in tendinous lesion management.
Open Access
Remodelling of collagen fibres in the placentas of women with venous insufficiency during pregnancy
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Ortega, Miguel A.; Asúnsolo, Ángel; Álvarez Rocha, María J.; Romero, Beatriz; De León-Luis, Juan; Álvarez Mon, Melchor; Buján, Julia; García Honduvilla, Natalio
Haemodynamic changes produced during pregnancy lead to elevated venous pressure in the legs and an increased resting consumption of oxygen. These events can cause varicose veins, or venous insufficiency (VI), which by creating an environment of hypoxia could affect the structure and function of the placental barrier. This study assesses the remodelling state of the placental villi by examining differences in collagens with a known role in villus structure and in placental barrier permeability between patients with and without VI. Samples of 67 placentas from women with VI (n=24) and without VI (n=43) during their pregnancy were processed for gene and protein expression analysis of COL-I, COL-III, MMP-2 and MMP-9 by RT-qPCR and immunohistochemistry. While no differences in COL-I expression levels were detected in the samples from women with and without VI, significant differences did emerge in both gene and protein expression levels of COL-III. Importantly, COL-I/III ratios were reduced in the VI group compared to controls. MMP-2 activity was similar in the two groups while MMP-9 levels were significantly elevated in VI with greatest expression differences observed at the level of the decidual cells. Mothers who developed VI during pregnancy showed significantly higher COL-III and MMP-9 levels consistent with a state of remodelling of the placental villi.
Open Access
Role of discoidin domain receptor 2 in wound healing
(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2014) Márquez, Joana; Olaso, Elvira
Until recently, collagen interactions with cells had been ascribed to integrins. The identification of the Discoidin Domain Receptor (DDR) family as collagen receptors represents a new paradigm in the regulation of collagen-cell interactions. How DDR signaling is biochemically linked to specific cell regulatory functions remains largely unknown. Moreover, the characteristic slow and substained phosphorylation of DDRs and the elevated expression of DDR2 in the myofibroblasts of healing wounds suggest a role for DDR2 in physiological and pathological wound healing. In fact, DDR2 signaling regulates cell proliferation and extracellular matrix synthesis, which are key aspects of fibroblast contribution to tissue healing. In this review we summarize evidence in favor of this concept.