EJMS

Abstract

Background: Corticosteroids are commonly used to accelerate fetal lung maturation and reduce the incidence of respiratory distress syndrome. Numerous clinical studies were performed to investigate the effect of corticosteroids on premature fetal lung but the histological ones are commonly deficient. Objective: To investigate the histological changes in the alveoli of premature fetal rats as a result to dexamethasone injection to their pregnant mothers. Design: Histological study of the pulmonary alveoli of premature fetal rats. Subjects: Two primary groups of adult rats, each consisted of 3 males and 12 females were used. Pregnant rats were classified into two secondary groups; control group and dexamethasone- treated one, given intramuscular injections of dexamethasone 1mg/kg body weight / day at 16th, 17th and 18th days of gestation. Results: In dexamethasone-treated premature rats; the alveoli were well inflated, their lumena were clear of blood elements and lined by thin alveolar membranes. Connective tissue elements in the interalveolar septa were markedly decreased. Pneumocytes 1 and 11 were well developed with increase in lamellar inclusion bodies of pneumocytes 11. Diffusion barriers became more thin and well corrugated. Conclusion: Dexamethasone administered to pregnant rats greatly improved the histological picture of the alveoli of premature fetal lung. Alveolar lumena and membranes are well developed. Diffusion barriers are more suitable for gas exchange. Corticosteroid therapy is advisable to pregnant mothers in need to – or will be exposed to – preterm delivery for more healthy neonates as it greatly improves the histological appearance of the lung.