[Regulation of ursolic acid on TNF-alpha and collagen in silicotic rats]

To explore the regulation of ursolic acid on the expressions of TNF-alpha and collagen on Silicotic Rats.

Seventy-five Wistar rats (class SPF) were divided into there groups according to the randomized block design, namely, control, model, ursolic acid groups with twenty-five rats in each group. SiO2 powders (250 mg/kg) were douched in the trachea of rat to make the silicotic model in model and ursolic acid groups. Ursolic acid (40 mg/kg) was injected into stomach cavity in ursolic acid group from the second day of SiO2, while the rats in control group were given sodium chloride in the same condition for 28 consecutive days. All rats were put to death on the 7th,14th and 28th day. TNF-alpha contents in serum were detected by ELISA. Total collagen contents in lung tissue were determined by hydroxyproline kits. Collagen I and III in lung tissue were investigated by western blot technique.

After four weeks of intervention, the contents of TNF-alpha in serum of the model group had rised, showing statistically significant difference in each time compared to those of the control group (P < 0.05). Ursolic acid had depressant effect on the contents of TNF-alpha (P < 0.05). Compared with control group, the content of total collagen was significantly improved in model group (P < 0.05). However, ursolic acid depressed the expression of total collagen protein compared to those of the model group (P < 0.05). The expression levels of collagen I and III in ursolic acid and model groups were similar with the total collagen.

Ursolic acid could decrease the expressions of TNF-alpha and collagen in the process of silicosis fibrosis.