The Possible Protective Effect of Corticosteroids on Bleomycin Induced Pulmonary Toxicity. Light and Electron Microscopic Study

Introduction: Bleomycin is an antitumor antibiotic having a high significant activity and wide use in the clinical field. The most serious adverse reaction to bleomycin therapy is the life-threatening pulmonary toxicity and fibrosis. Aim of the Work: Was to study the effect of bleomycin injection with and without corticosteroid on the lung of adult male albino rat using light and electron microscopy. Materials and Methods: 30 adult male albino rats were used dividing into two main groups; group A (control group), group B (experimental group) included 20 rats, ten rats each injected i.p with 0.5 mg of bleomycin sulphate twice weekly for four weeks and ten rats each injected i.p with 0.5 mg of bleomycin sulphate twice weekly for 4 weeks in concomitant with daily i.m. injection of 0.4 mg of prednisolone for the same period. Results: Bleomycin treatment induced variable degrees of lung injury disrupting the normal architecture. Overexpansion of alveoli alternating with collapse of others, congestion of blood vessels, cellular infiltration and fibrosis were all observed. Ultrastructurally, pneumocyte II showing disrupted mitochondria and destruction of lamellar bodies. Pneumocytes type II were predominant replacing the disappeared pneumocyte type I in the alveolar lining. Activation of alveolar macrophages and deposition of collagen fibres in the interstitial tissue were all noticed. Concomitant use of bleomycin with pridnisolone revealed the same histological changes. Only the pneumocyte type II proliferation was less and increase in collagen fibers deposition was not observed comparing with control. Conclusion: Corticosteroids inhibited or at least delayed pulmonary fibrosis induced by bleomycin treatment.