The Effects Of Sodium Ferulate On The Neuropathic Pain Mediated By P2X₃ Receptor In Gorsal Root Ganglion Neurons

Objective: To investigate the effects of sodium ferulate (SF) on the signal transmission of neuropathic pain mediated by P2X3 receptor in dorsal root ganglion (DRG.) of the rat .Methods:Chronic constriction injury (CCI) rat model was adopted. The rats have been randomly divided into five groups: groupâ… (NS group),â…¡(sham group),â…¢(CCI group),â…£(CCI+ SF group),â…¤(SF group). (1) Mechanical withdrawal threshold and thermal withdrawal latency were measured.(2) P2X3 immunoreactivity, P2X3 mRNA and P2X3 protein on L4/L5 DRG neurons were detected by immunohistochemistry, in situ hybridization and western blotting.(3) Whole-cell patch-clamp technique was used to study the effects of SF on P2X receptor agonists-activated currents in freshly isolated rat L4/L5 DRG neurons.Results: (1) Behaviour study: The mechanical withdrawal threshold and thermal withdrawal latency in groupâ…¢were lower than those in groupâ… ,â…¡,â…¤in 14 days after operation(p<0.05). The mechanical withdrawal threshold, thermal withdrawal latency in groupâ…£was higher markedly than that in groupâ…¢(p<0.05). There were no significant difference among groupâ… ,â…¡andâ…¤.(2) Immunohistochemistry, in situ hybridization and western blotting: the expression of the P2X3 protein and P2X3 mRNA in groupâ…¢decreased significantly compared to those in groupâ… ,â…¡,â…¤(p<0.05), the expression of the P2X3 protein and P2X3 mRNA in groupâ…£was higher markedly than that in groupâ…¢(p<0.05 or p<0.01 ). There were no significant difference among groupâ… ,â…¡, andâ…¤. (3) Whole-cell patch-clamp study: ATP-activated currents (IATP) on DRG in groupâ…¢was higher markedly than those in groupâ… ,â…¡,â…¤(p<0.05), ATP-activated currents (IATP) on DRG in groupâ…£decreased significantly compared to that in groupâ…¢(p<0.05). There were no significant difference among groupâ… ,â…¡, andâ…¤.Conclusion: The results show that the increasing expression of the P2X3 protein and P2X3 mRNA in DRG is involved in the signal transmission of neuropathic pain in CCI rats. SF may inhibit the signal transmission of neuropathic pain by reducing the expression of P2X3 receptor in the DRG of CCI rats.