OBJECTIVETo study the effect of intracellular reactive oxygen species (ROS) levels on T cell activation and apoptosis of synovial cells in collagen induced arthritis (CIA) rats, and to explore the mechanism of Fengshining Capsule (FSN) in the treatment of rheumatoid arthritis (RA).

METHODSSixty rats were randomly divided into the normal control group, the CIA model group, the Tripterygium Poly-glycoside Tablet (TPT) group, the low dose FSN group (at the daily dose of 0.33 g/kg), the middle dose FSN group (at the daily dose of 0.66 g/kg), and the high dose FSN group (at the daily dose of 1.32 g/kg), 10 in each group. T lymphocyte subsets were detected by flow cytometry. The content of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in plasma of rats were detected by ELISA. Its expression of hydroxyl radicals was detected by ultraviolet spectrophotometry. Caspase-3 and Caspase-9 protein expressions were measured by Western blot.

RESULTSCompared with the CIA model group, the levels of ROS were elevated in each dose FSN group (P < 0.01). The level of CD4+ / CD8 was significantly reduced in the middle dose FSN group (P < 0.01). The content of IFN-gamma was obviously lowered in each dose FSN group (P < 0.01), while that of IL-4 was obviously elevated in the high dose FSN group (P < 0.01). Meanwhile, the expression of Caspase-9 and Caspase-3 significantly increased in each dose FSN group (P < 0.05). Besides, the average gray scale of Caspase-9 was significantly higher in the low and middle FSN groups than in the TPT group (P < 0.05, P < 0.01).

CONCLUSIONThe mechanism of FSN for regulating the immune hyperfunction and inhibiting the proliferation of synovial cells in CIA rats might be associated with up-regulating in vivo ROS levels.