ABSTRACT
OBJECTS AND DESIGN: Regarding to anti-inflammatory role of interleukin (IL) 10, its inhibitory effects on p38MAPK activity and, different pro and anti-inflammatory roles of activated p38MAPK in cells, this study was aimed to investigate relationship between serum IL10 level and p38MAPK enzyme activity on behavioral and cellular aspects variation of hyperalgesia during different stages of arthritis in rats. MATERIALS AND METHODS: Adjuvant arthritis (AA) was induced by a single subcutaneous injection of complete Freund's adjuvant into the rats' hind paw. Behavioral and inflammatory responses were assessed at 0, 3, 7, 14, and 21 days of study. Receptor and other protein enzyme expression variations were detected by western blotting. Anti-IL10 and p38MAPK inhibitor were administered daily during the 21 days of study. RESULT: Daily treatment with anti-IL10 antibody significantly increased paw edema and hyperalgesia in the AA group compared with the AA control group. Administration of anti-IL10 antibody caused significant increase in the ratio of phosphorylated p38 to p38MAPK enzyme level expression on 14th and 21st days of study compared with the AA control group. CONCLUSION: Our study confirmed that a part of anti- inflammatory effects of serum IL10 during AA inflammation was mediated via inhibition of p38MAPK enzyme phosphorylation. Moreover, these findings suggest that increase in the level of spinal mu opioid receptor expression during AA inflammation is not mediated via the direct effect of serum IL10 on spinal p38MAPK.
