Pretreatment With Resveratrol Ameliorate Trigeminal Neuralgia By Inhibiting MMP-9 And 2

Object: Trigeminal neuralgia(TN)is a common type of neuropathic pain which is a clinical challenge since the underlying mechanisms remain poorly understood.Matrix metalloproteinase(MMP)is a kind of widely distributed multidomain endopeptidase that hydrolyze extracellular matrix and several other cytokines in vivo.Recently,accumulating evidence indicates that MMP-9/2 are widely implicated in the development of neuropathic pain.Resveratrol is a natural polyphenolic compound which is widely employed in anti-aging effect as well as cardiovascular protection due to its oxidation resistance and anti-inflammatory properties.Moreover,resveratrol has been reported to be able to ameliorate neuropathic pain,whereas the detailed mechanisms have not been fully elucidated.In this study,the key roles of MMP-9/2 in TN models were studied and the molecular mechanism of resveratrol in its analgesia effects were further explored.Methods:(1)The TN model was produced by chronic constriction injury to the unilateral infraorbital nerve(CCI-IoN).(2)The activity of MMP-9 and 2 were evaluated by Gelatin Zymography at different time points after CCI.The effect of resveratrol and the TLR-4 inhibiter on the activity of MMP-9 and 2 were evaluated as well.(3)A series of Von Frey fiber filament were used to measure the changes of mechanical allodynia after using a MMP-9/2 selective inhibitor or a TLR-4 inhibiter.Von Frey test was used to measure the changes of mechanical allodynia while giving resveratrol orally in different doses before or after pain formation.(4)Western blot was performed to test the effect of resveratrol on the expression level of IL-1?,TNF-?,p-PKC?,p-NR1,MMP-9/2 and p-p65.After using a TLR-4 inhibitor,the expression level of p-p65 was also be tested.The expression level of SOCS3 after CCI was measured when resveratrol was given orally in different doses before CCI,SOCS3 was also be tested after using AMPK inhibiter Compound C.Results :(1)Gelatin Zymography results showed MMP-9 and MMP-2 upregulated in the unilateral trigeminal ganglion(TG)after CCI.The activation of MMP-9 and MMP-2 could be inhibited by resveratrol in a dose-dependent manner and a TLR-4 inhibitor played an equivalent role.(3)A MMP-9/2 selective inhibitor could effectively relieve pain hypersensitivity induced by CCI and this mechanical allodynia could be significantly delayed and attenuated by resveratrol no matter the single administration before CCI or consistent administration before or after pain formation.The TLR-4 inhibitor could also effectively relieve this pain hypersensitivity induced by CCI.(4)The rapidly upregulation of IL-1? and TNF-? and phosphorylation of NR1 and PKC? induced by CCI were reversed by resveratrol.Both the TLR-4 inhibitor and resveratrol could reduce the upregulation of MMP-9/2 and p-p65 induced by CCI.Resveratrol which was given in single dose before CCI could induced the expression of SOCS3 in a dose-dependent manner,whereas this effect was reversed by the AMPK inhibitor compound C.Conclusion:Pretreatment with resveratrol could induce SOCS3 expression to negatively regulate TLR-4/NF-?B signaling pathway,suppressed the activity of MMP-9/2,and further inhibited neuroinflammation and alleviated pain sensitization.