Pastor García, Luis Miguel

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Pastor García, Luis Miguel

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Pastor García, Luis Miguel

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Universidad de Murcia. Departamento de Biología Celular e Histología

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Estudio microscopico del epitelio traqueal de Testudo graeca y pseudemys scripta elegans / Luis Miguel Pastor García.
(Murcia : Universidad,, 1985) Pastor García, Luis Miguel
Open Access
Ultrastructure of the tubular nephron of Testudo graeca (Chelonia). A comparison between hibernating and non-hibernating animals
(Murcia : F. Hernández, 1987) Zuasti, A.; Ferrer, C.; Ballesta Germán, José; Pastor García, Luis Miguel
The tubular nephron of hibernating and nonhibernating specimens of Testudo graeca (Chelonia) was studied by means of conventional light and electron microscopy and histochemistry. The tubular nephron was composed of proximal, intermediate, distal and collecting tubules in both hibernating and nonhibernating animals. The cells of the proximal tubule showed long microvilli, cytoplasmic vacuoles, a developed endoplasmic reticulum and abundant mitochondria. Fat droplets were also observed. The intermediate segment was lined by ciliated and nonciliated cells. The lining cells of the distal tubule presented few microvilli, abundant dense mitochondria and clear vesicles of mucous appearance in the terminal portion. Collecting ducts are composed of mucous and non-mucous cells. Mucous cells presented strong reaction to the histochemical techniques detecting sialoand sulpho-mucins. During hibernation, a progressive vacuolar degeneration of the endoplasmic reticulum was observed in al1 the segments of tubular nephron, which may be caused by a massive intake of extracellular water into the cell.
Open Access
Morphogenesis of rat experimental pulmonary emphysema induced by intratracheally administered papain: changes in elastic fibres
(Murcia : F. Hernández, 2006) Sánchez-Gascón, F.; Girona, J.C.; Bernal-Mañas, C.M.; Canteras, M.; Beltrán Frutos, Ester; Pastor García, Luis Miguel; Morales Bartolomé, Eva
The ultrastructural changes of elastic fibres in emphysematous lungs have been studied in men, but few works exist on this topic in experimental emphysematous animals. In this paper, the morphogenesis of emphysema and alterations of the elastic fibres produced by the instillation of papain are described by light and electron microscopy. Wistar rats were instilled through the trachea with papain at a rate of 3 mg/100 g animal weight. The animals were sacrificed 12 h, 3 days, 10 days and 60 days after enzyme instillation. The "Mean Linear Intercept" (MLI), the "Number of fenestrations/respiratory units" (NF) the “Number of macrophages per mm of alveolar wall” (NM) and the "Number of respiratory unit/mm2” (RU), both in the control and experimental groups were studied. Two months after treatment, the experimental group showed a strong increase in the MLI (p<0.001) and NF (p<0.001), and a diminished number of RU (p<0.05) compared with the control group. Partial correlation analysis showed a positive correlation only between MLI and NF. Twelve hours after papain instillation an inflammatory response was observed, the elastic fibres were ruptured, while the microfibrilar component remained. New formations of eulanin elastic fibres were observed three days post papain instillation. After ten days the interalveolar oedema had disappeared and the elastic fibres were of normal morphology although irregular groups of strips of elastic fibres were evident. A mixed pattern of panlobular, centrilobular and normal lung zones were observed. Two months after papain instillation abundant accumulations of elastic fibres of irregular outline were observed associated to collagen fibres. In conclusion, the morphometric parameters studied showed a significant progression of the emphysema. The strong correlation between NF and MLI suggested that papain-induced emphysema is principally caused by breaches of the alveolar walls. The results seem to point to a very abnormal remodelling process associated with elastic fibre regeneration, although there were no signs of destruction of these new fibres formed in emphysematous rat lung induced by papain.
Open Access
Heterogeneity of mesenchymal cells in human amniotic membrane at term
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Cortés Sandoval, Salvador; Serrano Sánchez, Mª Isabel; Ferrer, Concepción; Insausti, Carmen L.; Blanquer, Miguel; Beltrán Frutos, Ester; Martínez Hernández, Jesús; Pastor García, Luis Miguel; Seco Rovira, Vicente; Delgado Marín, Juan Luis
There is increasing interest in understanding the tissue biology of human amniotic membrane (hAM) given its applications in medicine. One cellular component is mesenchymal cells, which can be extracted, cultured and differentiated "in vitro" into various cell types. These studies show that there is heterogeneity among mesenchymal cells. The aim of this work is to study the membrane "in situ" to determine whether this cellular heterogeneity exists. The hAMs were obtained from caesarean deliveries at term and analyzed by histological techniques. Types I-III mesenchymal cells and Hofbauer were distinguished by light microscopy. Histochemically, mesenchymal cell types showed successively increasing positivity to: PAS, vimentin, fibronectin, and Concanavalin-A; VGEF, TGF-β2, PDGF-C, FGF-2. By the semiquantitative point of view, the percentage of Type II cells was 60%, significantly higher than the other types. With transmission electron microscopy, an intermediate cell type between II-III was observed. Strong vesiculation of the rough endoplasmic reticulum (RER) with exocytosis was observed. In addition, an accumulation of a similar material to the extracellular matrix in the RER caused its dilation especially in type IIITEM cells. Some of this material acquired a globular structure. These structures were also found free in the extracellular matrix. In conclusion, the mesenchymal cells of the fibroblastic layer of the hAMs studied are heterogeneous, with some undifferentiated and others with a probably senescent fibroblastic phenotype with accumulation in their RER of fibronectin. These results may be of interest to extract mesenchymal cells from hAMs for use in regenerative medicine and to better understand the mechanisms of fetal membrane rupture
Open Access
The oxytocin receptor in spermatozoa may originate from both spermatogenesis and epididymal maturation, and regulates capacitation
(Wiley, 2025-09-27) Garriga, Ferran; Ahmad, Adeel; Padilla, Lorena; Maside, Carolina; Bonet, Sergi; Barranco Cascales, Isabel; Roca, Jordi; Pastor García, Luis Miguel; Yeste, Marc; Martínez Hernández, Jesús; Medicina y Cirugía Animal; Facultad de Veterinaria
Background: The oxytocin receptor (OR) is a G-protein-coupled receptor recently identified in human spermatozoa, whose origin and role in sperm physiology remain unknown. Objectives: In this study, using the pig as a model, we examine the presence of the OR in ejaculated spermatozoa through immunofluorescence and immunoblotting, and investigate the receptor's origin in the male gamete via immunohistochemistry in testicular and epididymal tissues. Additionally, we assess the involvement of the OR in in vitro capacitation and the acrosome reaction by utilizing physiological concentrations of agonists (oxytocin and carbetocin) and an antagonist (L-371,257). Results: The results indicate that, in addition to the expected presence in ejaculated spermatozoa, the OR is expressed during spermatogenesis. Besides, this receptor is found in Leydig and Sertoli cells, as well as in the principal, basal, and apical cells of the epididymis. Furthermore, our data suggest that, during epididymal maturation, the OR could be incorporated in spermatozoa via extracellular vesicles within the apical blebs. The OR is involved in sperm capacitation, as the combination of the antagonist (L-371,257) and the agonist (carbetocin) increases intracellular calcium levels and membrane lipid disorders, which are known as capacitation markers. Conclusions: The presence of the OR in mammalian spermatozoa could originate from both spermatogenesis and epididymal maturation. Moreover, in the male gamete, this receptor regulates sperm capacitation by interacting with its ligand in the female reproductive tract.
Open Access
Ultrastructure of the renal corpuscle of Testudo graeca Chelonia. A comparison between hibernating and non-hibernating animals.
(Murcia : F. Hernández, 1986) Zuasti, A.; Ferrer, C.; Ballesta Germán, José; Pastor García, Luis Miguel
The renal corpuscle of hibernating and nonhibernating Testudo graeca was studied by means of light and electron microscopy. Renal corpuscles are small and have a glomerular architecture similar to that found in other vertebrates with a limited glomerular filtration rate. In hibernating animals, unlike non-hibernating, some n~orphologicacl hanges took place. The cells of the renal corpuscle were densely packed, podocytes and parietal cells bhowed a marked cytoplasmic vacuolization, there was a highly developed capillary basement membrane and the endothelial and mesangial cells showed abundant dense granules. These morphological features apparently correspond to a vacuolar degeneration. They may also be the morphological basis of the decrease in the glomerular filtration rate observed during this period.
Open Access
Posthatch development of the axial musculature of the common dentex Dentex dentex, L (Teleostei)
(Murcia : F. Hernández, 2010) Arizcun Arizcun, Marta; Abellán, E.; Blanco, A.; Ayala Florenciano, María Dolores; Latorre Reviriego, Rafael Manuel; López Albors, Octavio Miguel; Pastor García, Luis Miguel
The common dentex is a promising candidate for Mediterranean aquaculture. The present work is aimed at describing the development of the axial musculature from hatching to postlarval life. Transmission electron microscopy, histochemical (NADH-TR and mATPase) and immunohistochemical techniques (S-58 and TUNEL) have been used. At hatching superficial red and deep white muscles can be distinguished. Presumptive dermomyotome (external) cells are initially located over the superficial red muscle but shortly (2 days) tend to concentrate towards the epaxial and hipaxial limits of the myotome. Then, these cells enter the myotome and spread around and within the white muscle thus being apparently responsible for the stratified hyperplasia of the myotome. Mosaic hyperplasia is activated during the second half of the larval period and initially relies on differentiation of a population of atypical premyoblastic cells (APC). APC are mononuclear cells with euchromatic nuclei, cytoplasms full of thin longitudinally projected tubules, occasional mitochondria and scattered ribosomes. By the end of the larval period these cells tend to disappear, partly due to apoptosis, but postlarval mosaic hyperplasia continues by differentiation of presumptive myosatellite cells. APC are an unexpected and singular finding of this study which deserves more research, so as to further characterize their ancestry, developmental programme and fate. In addition to the white and superficial red muscle fibres, intermediate (pink) and tonic fibres appear during larval metamorphosis. Later, during the early postlarval life, a new type of slow twitch red muscle fibre is differentiated (red adult type).
Open Access
Granulocyte-macrophage colony stimulating factor (GM-CSF) is fully expressed in the genital tract, seminal plasma and spermatozoa of male pigs
(Nature Research, 2020-08-07) Padilla, Lorena; Barranco, Isabel; Lucas, Xiomara; Rodríguez-Martínez, Heriberto; Roca, Jordi; Parrilla, Inmaculada; Martínez Hernández, Jesús; Pastor García, Luis Miguel; Medicina y Cirugía Animal
Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pro-inflammatory cytokine identified in boar seminal plasma (SP) but until now unexplored in terms of place of production and its association to spermatozoa. This study aimed to explore these aspects by evaluating the presence of GM-CSF in porcine reproductive organs (testes, epididymis and accessory sex glands), SP and mature spermatozoa (from cauda epididymis and ejaculated) using Western blot (WB), immunohistochemistry and immunocytochemistry. Positive labelling was obtained in tissues, SP and spermatozoa. In reproductive organs, WB revealed three forms of GM-CSF with different glycosylation degrees (15, 31 and 40 kDa). In SP and epididymal fluid, the GM-CSF appeared only in its active form while in spermatozoa the GM-CSF form present varied among sperm sources. Non-viable spermatozoa showed more GM-CSF than viable spermatozoa (14.87 ± 1.98 RU vs. 7.25 ± 0.52 RU) of fluorescence intensity. In conclusion, GM-CSF is widely present in the reproductive tract of male pigs, attached to the spermatozoa already in the epididymis as well as verted to SP. Consequently, the GM-CSF ought to regulate male genital tract and sperm function as well as mediating initial inflammatory responses and further mediating later immune actions by the female to semen deposition.
Open Access
HSP47 expression in the hamster Sertoli cell: An immunohistochemical study
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2024) Serrano-Sánchez, María Isabel; Ferrer, Concepción; Beltrán Frutos, Ester; Martínez Hernández, Jesús; Pastor García, Luis Miguel; Seco Rovira, Vicente
HSP47, a chaperone whose main function is the maturation of collagen molecules, is considered a marker of fibrotic diseases. Increased collagen synthesis in the testis has been associated with various pathologies leading to seminiferous tubule regression. Our aim was to study whether HSP47 is expressed in hamster Sertoli cells both in the adult and in two physiological situations of seminiferous tubule atrophy: irreversible testicular ageing and testicular regression due to short photoperiod (reversible). Eighteen animals were divided as follows: a group of 6 young animals aged 6 months, a group of 6 animals aged 24 months, which were exposed to a long photoperiod, and a final group of 6 young animals subjected to a short photoperiod. Testicular samples were fixed in methacarn and an immuno-histochemical technique was used to detect HSP47. A semiquantitative study of this protein expression was performed between tubular sections of aged animals with complete spermatogenesis and arrested spermatogenesis and tubular sections with arrest spermatogenesis of photoinhibited testes. Sertoli cells were positive for HSP47, the intensity being greater in tubular sections with arrested spermatogenesis in both aged and photoinhibited animals. Semiquantitative analysis corroborated this observation in the sense that the expression of this protein differed according to the functional state of the seminiferous tubules. Thus, the ratio of immunoreactivity was significantly higher in tubular sections with arrested spermatogenesis in aged animals compared with regressed animals, and in the latter compared with those whose tubular sections showed complete spermatogenesis. In conclusion, HSP47 expression in Sertoli cells was found for the first time in mammals. Moreover, increased expression seemed to be related to the degree of seminiferous atrophy epithelium and to the reversible or nonreversible physiological state of this epithelium.
Open Access
Involution of seminiferous tubules in aged hamsters: an ultrastructural, immunohistochemical and quantitative morphological study
(Murcia : F. Hernández, 2004) Horn, R.; Santamaria, L.; Pallarés, J.; Zuasti, A.; Ferrer, C.; Canteras, M.; Pastor García, Luis Miguel; Morales Bartolomé, Eva
In this study, we examined the age-related changes on morphometric parameters and ultrastructure of seminiferous tubules, and on the expression of extracellular matrix proteins in lamina propria of Syrian hamsters. A significant decrease in the percentage of normal tubules and an increase in the percentage of hypospermatogenic and arrested maturation tubules was observed with aging. Aged animals showed a decrease in tubular diameter, tubular lumen, seminiferous epithelium volume and total tubular volume. However, the total length of seminiferous tubules was significantly increased with aging. The most important ultrastructural changes with aging were the thickening of the lamina propria, the presence of diverse abnormalities in the spermiogenesis process, degeneration of germ cells, and vacuolization and flattening of Sertoli cells showing abundant lipofucsin droplets and residual bodies. Laminin immunoreactivity was found along the lamina propria of seminiferous tubules both in young and aged animals. Fibronectin immunoreactivity was found along the lamina propria and blood vessels. Both laminin and fibronectin total volume of immunostaining per testis was increased in aged hamsters. In conclusion, the agerelated changes in seminiferous tubules of hamster include: a decrease in tubular width and an increase in tubular length; widening of the lamina propria caused by a more extensive connective matrix between the peritubular cells and the basal membrane; and a strong disarrangement of the seminiferous epithelium, including germ cell degeneration and important alterations in both spermiogenesis and Sertoli cell structure.