role of matrix metalloproteinase ii on analgesic effect of nitric oxide inhibition in rat

abstract introduction: matrix metalloproteinase 2 is one of the inflammatory mediators that is involved in nociceptive processing and its production is regulated by many inflammatory factors such as nitric oxide. we studied the role of mmp-2 on the analgesic effects of nnos inhibitor. methods: considering that nitric oxide has many roles in pain processing, we studied the csf levels of mmp-2 after hind paw formalin injection (50µl, 2.5%) and neuronal nitric oxide synthase inhibition intrathecally. we also studied the effect of mmp-2 inhibitor on pain behavior and its role on analgesic effect of neuronal nitric oxide synthase (nnos) inhibitor. results: rats that received mmp-2 inhibitor (30mm) showed severe responses to the formalin injection. pain was reduced after nnos inhibition. prior to nnos inhibitor injection, mmp-2 inhibition reduced the analgesic effects of nnos inhibitor. immunological study showed that mmp-2 increased in rats that received nnos inhibitor. conclusion: these data suggest the possible roles for mmp-2 in analgesic effect of nnos inhibitor.