The contribution of type II pneumocytes and alveolar macrophages to fibroplasia processes in the course of enzymatic lung injury

• Sulkowska, M. ^[1] ; Sulkowski, S. ^[1]
  1. [1] Department of Pathological Anatomy, Medical School of Bialystok, Bialystok, Poland
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 12, Nº. 1, 1997, págs. 111-122
• Idioma: inglés
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  • The aim of the paper was to evaluate mutual relations in the system of alveolar macrophage (AM) - type I! pneumocyte (PII) - interstitium of alveolar septa, in the course of experimental lung emphysema in rats subjected to BCG vaccine effect.

    Administration of BCG vaccine resulted in the cumulation of AM within pulmonary alveoli. These cells exhibited morphological features of increased activity.

    Intratracheal papain injection induced intralobular emphysema changes, partly generalized, in the animal lungs. The emphysematous changes, with domination of interalveolar se ptum atrophy, were accompanied by focal accumulation of collagen and elastin. Fibroplasia processe s were strongly pronounced in BCG- and papain-treated animals. The areas of connective tissue fibres cumulation revealed indistinctne ss of the boundary line between PII and the interstitium in some places. Anchorage of collagen fibres and microfibrillary structures were observed in the cytoplasm of PH.

    The morphological examinations of AM - fibroblasts co-cultures as well as the evaluation of the uptake of 3Hthymidine did not show any significant difference s between respective co-cultures of fibroblasts and AM isolated both from the lungs of control and experimental animals (treated with BCG or papain , and BCG+papain).

    However, a significant growth was noted in 3Hthymidine uptake between fibroblast cultures realized with or without cells isolated from the lungs.

    The results obtained suggest the possibility of active participation of PI! and AM in fibroplasia processes in the course of lung rebuilding after papain administration and in pathological states of the pulmonary tissue , particularly when they are accompanied by increased activity of alveolar macrophages. They also support the inflammatory-repair hypothesis in the development of emphysematous changes.