The Expression of Fas/Bcl-2 and Apoptosis in the Epithelial Cells of Pulmonary Fibrosis Rats

Objective To study the effect of apoptosis and Fas / Bcl-2 in the pathogenesis of pulmonary fibrosis.Methods Fouty-eight Sprague Dawley(SD)rats were randomly divided into two groups:normal control group(A group),model control group(B group).The model group were induced to produce pulmonary fibrosis with bleomycin endotracheally while the control group was given with normal saline instead in the same condition.Eight rats in model group were sacrificed on 7,14,and 28 days respectively after intratracheal instillation.Pathological changes in the lungs were evaluated by HE stain.The mRNA expression of Fas and Bcl-2 was evaluated by RT-PCR quantitative analysis,and the immunohistochemical method was used to investigate the change of Fas and Bcl-2 protein.TUNEL was used to detect the change of cell apoptosis. Results The percentage of cell apoptosis detected by TUNEL in alveolar and bronachial epithelial cells of pulmonary fibrosis rats was higher than the normal control groups.The result of immunohistochemistry and RT-PCR suggested that the expression of Fas mRNA and Fas protein in model groups was higher than the normal control groups.The expression of Bcl-2 mRNA and Bcl-2 protein in model groups was lower than the normal control groups.The difference was significant(P0.01).The result of immunohistochemistry and RT-PCR suggested that the expression of Fas protein and mRNA in alveolar and bronachial epithelial cells of pulmonary fibrosis rats also increased after 7 days by treating with bleomycin,increased on the 14th day and further increased on the 28th day;the expression of Bcl-2 protein and mRNA also decreased after 7 days by treating with bleomycin,reaches the trough on the 14th day.Conclusions Higher expression of aoptosis in alveolar epithelial cells and Bronchial cells of pulmonary fibrosis rats can contribute to fibrogenesis;the apoptosis index of lung cells,Fas gene and protein up-regulated and Bcl-2 gene and protein down-regulated in lung tissue of pulmonary fibrosis,which may play an important role in the development of pulmonary fibrosis.