Study On Effects Of 1,8-cineole On Neuropathic Pain Mediated By P2X₂ Receptor

Objective:To observe of the effect of 1,8-Cineole on the P2X₂ receptor expression in rats'spinal cord dorsal horn with neuropathic pain,and to investigate the effect mechanism on neuropathic pain induced by 1,8-Cineole.Methods:The chronic constiction injury?CCI?rats were used as the neuropathic pain model.The rats were randomly assigned into five groups:sham group?Sham?;chronic constriction injury group?CCI?;CCI rats with dimethysulfoxide control group?CCI+DMSO?;CCI rats treated with low dose 1,8-cineole group?CCI+50mg/kg?;CCI rats treated with high dose 1,8-cineole group?CCI+100mg/kg?.We observed the effects of 1,8-cineol on rats mechanical withdrawal threshold?MWT?and thermal withdrawal latency?TWL?.We examined P2X₂receptors mRNA change in rat spinal cord by qRT-PCR and in situ hybridization methods.Western Blotting and immunohistochemical staining methods were used to observe P2X₂ receptor protein expression in rat spinal cord.Results:?1?Pain behavior detection:At 7th and 14th days after surgery,group II,group?,group?and group?showed lower MWT and TWL than group I?P<0.01?,Group IV and?showed higher significantly than group II and group III?P<0.05?,while Compared with group IV,group?were obviously increased?P<0.05?,no obvious difference between group II and group III?P>0.05?.?2?Immunohistochemistry,in situ hybridization,qRT-PCR and western blotting:Compared with I,II,?,group?and group?P2X₂ receptor proteins and the expression of P2X₂mRNA in the rat spinal cord obviously increased?P<0.01?,group IV and group?were decreased significantly than group II and group??P<0.05?,while group?was significantly lower than group IV?P<0.05?,there was no significant difference between group?and group??P>0.05?.Conclusion:Oral administration of 1,8-eucalyptus can reduce the pain symptoms of the CCI rats and inhibit the overexpression of P2X₂ receptor mRNA and protein in the posterior horn of spinal cord in the CCI rats.