[Study of quercetin on pulmonary fibrosis by silica particles].

Objective: To observe the intervention effect of quercetin to silica dust cause pulmonary fibrosis.

Methods: Forty-eight healthy male adult SPF SD rats were selected and they were randomly divided into six groups (control group, 7 d,14 d,21 d and 28d dust group, preventive group). Rats in the control group were administrated 1 ml saline via trachea injection. Rats in dust group and preventive group were give silica solution for 1ml at dose of 50 mg/ml, and the prevention group with quercetin of 50 mg/kg every day lavage treatment intervention. In building on days 7,14,21,28 later, the lung tissue were removaled to HE staining for determining the degree of alveolitis and pulmonary fibrosis. The content of hydroxyproline (HYP) and the activities of catalase (CAT) and glutathione peroxidase (GSH-Px) were detected by using the kits.

Results: Alveolar septal edema, inflammatory cell infiltration and fibrosis were not found in control group. In the preventive group, lots of inflammatory cells infiltration were observed on days 7. Inflammatory cells were reduced, the number of the fibroblasts and matrix in alveolar septum were obviously increased, and alveolar structure was damaged on day 14. Pulmonary fibrosis was increased, severe fibrosis was found on day 28. Silicon dust after infected lung tissue expression of HYP content increased, the activity of CAT and GSH-Px decrease gradually. After joining quercetin the expression of HYP content gradually reduce, CAT and GSH-Px activity increased, the difference was statistically significant (P<0.05).

Conclusion: Quercetin of silica dust caused by pulmonary fibrosis have certain prevention.