Aim To investigate the expression of
matrix metalloproteinase-9 (MMP-9) in mouse ears induced with croton oil and the inhibitory
effect of dexamethasone,
indomethacin and resveratrol on MMP-9 expression, and further explore the relationship between anti-inflammation and MMP-9 inhibition of these three medicines. Methods Immuno-histochemistry was used to detect the expression of MMP-9 in mouse ears. Expression of MMP-9 in U937 cells was analyzed by gelatin zymography. Results Mouse ear edema induced with croton oil was inhibited significantly by dexamethasone and indomethacin at the dose of 10 mg·kg -1 and resveratrol at 50 mg·kg -1 administered subcutaneously. The inhibitory rate was 76.2% ( P <0.001), 56.7% ( P <0.001) and 36.9% ( P <0.001) respectively. The MMP-9 expression increased in mouse ears induced with croton oil and inhibited by dexamethasone, indomethacin and resveratrol at above doses. Gelatin zymography results showed that MMP-9 expression in U937 cells increased significantly after exposed to PMA at 1×10 -8 mol·L -1 ( P <0.001); MMP-9 expression induced with phorbol myristate acetate(PMA) was inhibited by dexamethasone at 1×10 -9 , 1×10 -7 and 1×10 -5 mol·L -1 , indomethacin at 1×10 -6 and 1×10 -5 mol·L -1 and resveratrol at 1×10 -6 and 1×10 -5 mol·L -1 . Conclusion The inhibition of MMP-9 expression may be one of the anti-inflammatory mechanisms of dexamethasone, indomethacin and resveratrol.