histological and immunohistochemical study on the possible role of vitamin a in ameliorating lung injury of mice exposed to toluene

ABSTRACT

Toluene is a widely used solvent in various industries and commercial products in Egypt; as colour mixers, painters, printers and petrol truck drivers. It represents a worldwide problem in environmental contamination and a common cause of occupational and non-occupational lung diseases. Studying the effects of toluene on the lung of mice histologically and immunohistochemically as well as evaluating the possible ameliorating role of vitamin A. Twenty-five adult male mice were divided into; group I [control], group II [each mouse was exposed to 50 ppm toluene inhalation for 6 hours daily/5days /week for 6 weeks] and group III [each animal was given 1.0 ml corn oil orally/day containing 910 IU of vitamin A after last toluene exposure for 6 weeks]. The lungs were processed for histological and immunohistochemical examination. Toluene inhalation led to focal areas of collapse alternating with over expanded alveolar spaces, congested vessels and degenerated alveolar epithelium. There was a statistically highly significant thickening of the interalveolar septa and fibrosis. Mice treated with vitamin A after toluene exposure, showed amelioration of these changes with appearance of many cuboidal regenerating cells. There was a highly significant increase of CD44v6 immunoreaction in group II and a non significant change in group III. It could be concluded that the environmental toxicant, toluene, induced histological and immunohistochemical changes in the lung. Amelioration of such changes by vitamin A, might direct the attention to vitamin A and carotenoids as protective measures for the lung