The modifications produced in allergic alveolitis and in goodpasture's syndrome due to exposure to cigarette smoke

Abstract

Two groups of rats with experimental alveolitis were exposed to cigarette smoke. After comparing the results, the possible muffling effect of the cigarette smoke related to interstitial lung disease was discussed. 180 rats were divided into 6 groups of 30 animals each: Group 1: untreated controls; Group 2: exposed to cigarette smoke for 2 months: Group 3: sensitized with bovine albumin (BA) and exposed to an atmosphere with this antigen for two months, to reproduce a type of extrinsic allergic alveolitis (EAA); Group 4: treated with a single daily dose of anti-lung serum for three days followed by two days without treatment, to reproduce a type of Goodpasture's syndrome; Group 5: exposed to cigarette smoke and to BA; Group 6: exposed to cigarette smoke and treated with anti-lung serum. The animals were sacrificed and their lungs were treated for: Bronchoalveolar lavage (BAL), percentage lymphocyte count, polymorphonuclear (PMN) and alveolar macrophages (AM); semiquantitative and morphometric histological study. The semiquantitative study determined the area of the studied lung incision, affected by granulomae, increased alveolar aerial spaces, thickened alveolar walls and haemosiderine lung area. The morphometric study, based on the linear integration method, evaluated: the distance between two alveolar walls, the amount of interstice per field; and the number of AM with haemosiderine per field was counted. From the results we point out that the treated animals had significantly higher lymphocyte and BAL PMN counts than the untreated ones; no significant differences were found between the singly and doubly treated animals. The animals exposed to cigarette smoke and treated with anti-lung serum were those that showed the least number of lymphocytes and PMN of all the treated animals. The semiquantitative variables studied were all increased in comparison to the control group, most of the increases being significant. The morphometric variables revealed significant differences with respect to the untreated group, except for the animals which were treated with anti-lung serum and cigarette smoke, which showed a minimum decrease in the alveolar size and a slight increase of the interstitial tissue. Only one morphometric variable showed a significant difference between the group treated with anti-lung serum and the one treated with anti-lung serum and cigarette smoke: the number of AM with haemosiderine in the lung. From the results we conclude that: 1) exposure to cigarette smoke causes alveolo-interstitial alterations which are detected by means of BAL and histology; 2) these alterations have no adjuvant effect when combined with the administration of BA; 3) the alveolo-interstitial affection found in the animals exposed to cigarette smoke and anti-lung serum is lower than in the animals which were only given anti-lung serum.