The protective effect of Hedyotis diffusa on collagen induced arthritis rats

Objective: To investigate the protective effect of Hedyotis diffusa (HD) on collagen induced arthritis (CIA) rats. Methods: 40 male Wistar rats were randomly divided into four groups: normal group (blank control, n = 10), CIA model group, HD low dose group and HD high dose group. After CIA rats were prepared successfully, HD extract was administrated orally with the dose of 6 g/(kg. d) and 12 g/(kg. d) to low and high dose group at day 14; normal group was administrated with the same volume of saline. The arthritis index was evaluated weekly after treatment. Rats were sacrificed at day 42, their serum IL-1β, TNF-α levels and nitric oxide (NO) concentration in synovial tissues were measured and compared. The annexin I expression in each groups were measured. The active status of PI3KAKT signal pathway was examined by western blot. Result: The arthritis index of HD low dose group was significantly lower than model group at day 35 and day 42 (P<0.05). The arthritis index of HD high dose group was significantly lower than model group at day 28, day 35 and day 42 (P<0.05). Histological analysis of joints showed that synovitis and osteoclastic bone resorption were attenuated by daily oral administration of HD. The expression of IL-1β and TNF-α in HD treatment groups were significantly lower than model group (P<0.05), as well as NO concentration in cartilage tissue. We observed significantly higher expression of annexin-Ι in HD treatment groups than model group (P<0.05). Conclusion: HD could reduce the expression of inflammatory cytokines IL-lβ and TNF-α and alleviate the inflammatory reaction and bone erosion in CIA rats.