RESUMO
<p><b>OBJECTIVE</b>To 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).</p><p><b>METHODS</b>Sixty 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.</p><p><b>RESULTS</b>Compared 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).</p><p><b>CONCLUSION</b>The 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.</p>