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

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-alpha) and interleukin-1beta (IL-1beta), as well as the activity of nuclear factor-kappaB (NF-kappaB) and the inhibitory kappaB-alpha (IkappaB-alpha) 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-alpha and IL-1beta were detected with reverse transcription-polymerase chain reaction (RT-PCR) and NF-kappaB activity was measured by electrophoretic mobility shift assay (EMSA). The IkappaB-alpha protein level in the cytoplasma was detected by Western blot. Our results showed that expression of mRNAs of TNF-alpha and IL-1beta and NF-kappaB activity by PMs and synoviocytes were markedly increased compared to control group (P<0.05). In a definite concentration ranging from 30 to 120 microg/ml, SN showed inhibiting effect on the NF-kappaB activity and the expression of the mRNAs of TNF-alpha and IL-1beta in AA rats in a concentration-dependent manner (P<0.05). Positive correlations were found between changes of NF-kappaB activity and expression of TNF-alpha mRNA and IL-1beta mRNA (P<0.01). IkappaB-alpha 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-alpha and IL-1beta by inhibiting the NF-kappaB binding activity, which is mediated through up-regulating the IkappaB-alpha expression of PMs and synoviocytes in AA rats.