To investigate the effects of cordycepin on cartilage repair, serum inflammatory factors and oxidative stress in rats with osteoarthritis.

Forty-five rats were randomly divided into control group, model group and low-,medium-, and high-dose cordycepin groups (10, 20, and 50 mg·kg·d^-1 by gavage) . The knee osteoarthritis model has been established using Hulth method. One week after modeling, rats in each group were administered the corresponding doses of cordycepin by gavage for 28 days. HE staining and Alcian blue staining were used to observe and compare the cartilage morphology of each group. MicroCT was used to detect and calculate the bone volume fraction, bone area fraction, trabecular bone thickness and trabecular bone number. The expression of cartilage matrix protein was detected by Western blot. The contents of interleukin (IL)-6, tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1 and IL-10 in serum of rats were determined by ELISA. The levels of oxidative stress markers in serum were detected by the kits.

Compared with the control group, cartilage tissue were showed significant pathological damage in the model group, bone volume fraction and bone area fraction were increased, and trabecular thickness and number were decreased (P<0.05); the protein expression levels of sex determining region Y-frame protein 9 (SOX-9), aggrecan, and collagenⅡ were decreased (P<0.05); the levels of IL-6, TNF-α, and MCP-1 in serum were increased, SOD and GSH activity were decreased, and MDA content was increased (all P<0.05). Compared with the model group, the pathological damage of knee cartilage tissue were significantly alleviated in the medium- and high-dose cordycepin groups, the bone volume fraction and bone area fraction were decreased, and trabecular thickness and number were increased ( P<0.05); the protein expression levels of SOX-9, aggrecan, and collagen Ⅱ were increased (P<0.05); serum IL-6, TNF-α, MCP-1 contents were decreased, IL-10 content was increased, MDA content was decreased, and SOD and GSH activity were increased (all P<0.05), showing a dose-dependent trend.

Cordycepin can reduce cartilage damage in rats with osteoarthritis by reducing inflammation and oxidative stress.