Bleomycin toxcity is characterized by destruction of-

Ans. is 'b' i.e., Type I Pneumocytes Bleomycin is well known to cause pulmonary toxicity.The incidence of bleomycin induced pulmonary toxicity is 5% for a total cumulative dose of450 units and 15% for higher dosages.Bleomycin is concentrated preferentially in the lung and is inactivated by hydrolase enzyme. This enzyme is relatively deficient in lung tissue.This may explain relative sensitivity of bleomycin to lung tissuePathological features of bleomycin toxicityEarly endothelial cell damageDestruction of type I pneumocytes^Migration of type II pneumocytes into alveolar spaces inducing interstitial changesType I epithelial cells are more vulnerable to bleomycin toxicity and are destroyed by bleomycin QFollowing destruction of type I pneumocytes repair is characterized by hyperplasia and dysplasia of type II pneumocytesFibroblast proliferation with subsequent pulmonary fibrosis is probably the basis for irreversible changes induced by bleomycin.Also knowHistopathology of lung in Bleomycin toxicityEndothelial cell edema and blebbingNecrosis of type I pneumocytesHyperplasia and metaplasia of type II pneumocytesInflammatory infiltrate with PMNProliferation of fibroblast and fibrosis