A Histological and Immunohistochemical Study on the Possible Role of Vitamin A in Ameliorating Lung injury of Mice Exposed to Toluene

Background: Toluene is a widely used solvent in various industries and commercial products in Egypt; as colour mixers, painters, printers and petrol track drivers. It represents a worldwide problem in environmental contamination and a common cause of occupational and non-occupational lung diseases. Aim of the Work: Studying the effects of toluene on the lung of mice histologically and immunohistochemically as well as evaluating the possible ameliorating role of vitamin A. Materials and Methods: 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. Results: Toluene inhalation led to focal areas of collapse alternating with overexpanded 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. Conclusion: It couldbeconcludedthatthe environmental toxicant, toluene, inducedhistological 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.