[Effect of Chinese herbal drugs and tetrandrine on TGF-beta1 signaling pathway].

OBJECTIVE: To investigate the molecule mechanism of the anti-fibrotic effects of Chinese herbal drugs (Qidan granules) in rats. METHODS: The male rats were randomly divided into four experimental groups: normal group, model group, Qidan group, tetrandrine group. Every group had 10 rats. Normal group were treated with physiologic saline while others were treated with silicon dioxide (50 mg/rat) by intratracheal instillation to induce silicosis. On 30th day Qidan group and Tetrandrine group were treated with Qidan granules (3125 mg/kg) or treated with tetrandrine (22 mg/kg) respectively. All the rats were scarified after 5 months. Lung/body coefficient was measured. Content of hydroxyproline was measured by alkaline hydrolysis. The gene expression of transforming growth factor-beta1 in bronchoalveolar lavage fluid was examined by using enzyme-linked immunosorbent assay (ELISA). The gene expressions of transforming growth factor-beta1, transcription factor Smad 3 and Smad 7 in lung were analyzed by using immunohistochemical technique (SP) and the image analysis. RESULTS: Model group mainly had Grade III approximately IV silicotic nodule while Qidan group and tetrandrine group had Grade II silicotic nodule. In Qidan group and tetrandrine group, lung/body coefficient and content of hydroxyproline and expression of transforming growth factor-beta1 and Smad3 in lung and expression of transforming growth factor-beta1 in bronchoalveolar lavage fluid were lower than those in model group (P < 0.05). Expression of Smad 7 in lung was higher than model group (P < 0.05). Injury of kidney occurred in tetrandrine group. CONCLUSION: Qidan granules and tetrandrine could inhibit expression of both Smad 7 and transforming growth factor-beta1 and promote expression of Smad 3. Qidan granules and tetrandrine could inhibit remarkably silicotic fibrosis in rats. Qidan granules are safer than tetrandrine.