effect of unleaded benzene on the pulmonary alveoli of albino rats: an ultra structural study

ABSTRACT

Benzene is a familiar and important commodity. It is a colorless, aromatic liquid that evaporates rapidly under ordinary atmospheric conditions. About Ninety-four percent of that total world product was produced by the petroleum and petrochemical industries, with the remainder produced by the steel industry as a byproduct of coking operations. Benzene is used in manufacturing a variety of products including motor fuels, solvents, detergents, pesticides, and other organic chemicals. The study evaluates the effect of chronic exposure to unleaded benzene on the lung alveoli. This study was carried out on thirty adult male albino rats divided equally into three groups. F Group I included ten unexposed rats, to be considered as a control group. Group II included ten rats exposed to 80 mg/m3 of unleaded benzene for 6 hours per day, 5 days a week for 6 months. Group III rats were exposed to 200 mg/rn3 of unleaded benzene for 6 hours per day, 5 days a week for 6 months. The alveolar structure of rat lung for all groups was examined by transmission electron microscopy. The present work demonstrated that exposure to 80 mg/rn3 unleaded benzene for six months resulted in pulmonary congestion with cellular infiltration, some pneurnocytes type II showed atypical empty lamellar bodies. While rat lung of group III. showed changes in the lining epithelium of the alveoli. Some pneumocytes type II showed generative changes involving their mitochondria and atypical lamellar bodies. While few pneumocytes type 11 appeared shrunken with dark stained cytoplasm. There was marked thickening in the interalveolar septa with cellular infiltration and collagen deposition. It is recommended that frequent change of gas station workers can avoid such deleterious inhalation effects secondary to prolonged exposures, also, more research should be done to discontinue or lessen the addition of such oxygenates [as MTBE] to the commercially used benzene