Depression effect of proanthocyanidins on expression of pulmonary TGF-β_1 and HSP47 in silica exposed rats

Objective To explore the effect of proanthocyanidins(PC)on the pulmonary fibrosis in silica-exposed rats.Methods Ninety-six SD rats were randomly divided into four groups:control group,silicosis group,low dose and high dose PC groups,24 rats in each group.Silica(50 mg/ml)was given by direct tracheal instillation;PC groups were administered with PC by gastric lavage at dose of 50 mg/(kg·d)(low dose group)and 500 mg/(kg·d)(high dose group)respectively at the second day of exposure to silica,rats in control and silicosis group were administered with saline solution at the same time.Eight rats for each group were killed at the 14,28 and 60 days after silica instillation,take the blood and lung tissue samples rapidly.The expressions of TGF-β1 and HSP47 in lung tissues were detected by immunohistochemical analysis,the activity of SOD in serum was also measured.Results Compared with that of control group,activity of SOD was decreased significantly at 28th and 60th days after silica exposure,the expressions of TGF-β1 and HSP47 were increased significantly with the time;while activity of SOD in high dose PC group was increased significantly(P0.05),and expressions of TGF-β1 and HSP47 in both low and high dose PC groups were decreased significantly(P0.05)compared with that in silica exposed group at the 60th day after silica exposure.Conclusion PC administration could increase activity of serum SOD and reduce expression of TGF-β1 and HSP47 in lung,which suggested that PC might have the effect of relieving pulmonary fibrosis caused by silica.