Effect of Electroacupuncture on Neurotoxicologic Screening of Sciatic Nerve And Expression of P2X_3 Receptor in Dorsal Root Ganglion of Rats with Chronic Constrictive Injury

Objective: To observe the effect of EA on neurotoxicologic screening of sciatic nerve and the expression of P2X3 receptor in the DRG of rats withCCI,so as to screen the neurotoxicological effect on sciatic nerve and to determine the role of P2X3 receptor in EA analgesia.Method: A total of 32 SD rats were randomly divided into 4 groups:Sham-CCI group,CCI model group,healthy limb EA group and affected limb EA group,with 8 cases in each group.The TWL and MWT were measured before CCI operation and at days3,5,7,10,12 and 14 after CCI operation.EA began at day 7 after CCI operation and then resumed once daily until the rats were killed at day 14 after the last EA treatment.EA was respectively applied to Zusanli acupoint(ST36) and Yanglingquan acupoint(GB34).The sciatic nerve samples were obtained for neuropathological examination under light microscope.The expression of P2X3 receptor in the L5 DRG of rats was detected by means of immunofluorescence techniques.Result: In the CCI group,the pain thresholds were decreased obviously compared with before CCI operation(P0.01).In the EA groups,the thermal and mechanical threshold values were increased(P0.05)but still had a significant difference compared with the normal and sham-CCI groups after the last EA treatment.There was no significant difference in light microscopic neuropathological examination among four groups.There was decreased expression of P2X3 receptor in the EA groups compared with CCI model group,and the expression value was decreased more significantly in the affected limb EA group than the healthy limb EA group.Conclusion: EA analgesia may be through decreasing the expression of P2X3 receptor in the DRG of rats with CCI and the affected limb EA treatment has better effect than the healthy limb EA treatment.No morphological evidence of neurotoxicity in the sciatic nerve of rats can be found.