Effect of sinomenine on cytokine expression of macrophages and synoviocytes in adjuvant arthritis rats

Abstract

For exploring the mechanism of the anti-inflammatory and anti-rheumatic effect of sinomenine (SN), the actions of different dosage of SN were observed in vitro on the expression of cytokines, tumor necrosis factor (TNF-α) and interleukin-1β (IL-1β), as well as the activity of nuclear factor-κB (NF-κB) and the inhibitory κB-α (IκB-α) protein level of peritoneal macrophages (PMs) and synoviocytes in adjuvant arthritis (AA) rats. In this study, the experimental rat model of AA was used and PMs and synoviocytes were collected. The mRNAs of TNF-α and IL-1β were detected with reverse transcription-polymerase chain reaction (RT-PCR) and NF-κB activity was measured by electrophoretic mobility shift assay (EMSA). The IκB-α protein level in the cytoplasma was detected by Western blot. Our results showed that expression of mRNAs of TNF-α and IL-1β and NF-κB activity by PMs and synoviocytes were markedly increased compared to control group ( P < 0.05). In a definite concentration ranging from 30 to 120 μg/ml, SN showed inhibiting effect on the NF-κB activity and the expression of the mRNAs of TNF-α and IL-1β in AA rats in a concentration-dependent manner ( P < 0.05). Positive correlations were found between changes of NF-κB activity and expression of TNF-α mRNA and IL-1β mRNA ( P < 0.01). IκB-α protein level was increased by various dosages of SN in comparison with control group ( P < 0.01). In conclusion, SN decreases the mRNA expression of TNF-α and IL-1β by inhibiting the NF-κB binding activity, which is mediated through up-regulating the IκB-α expression of PMs and synoviocytes in AA rats.