电针对慢性坐骨神经压迫性损伤大鼠神经病理学及背根神经节P2X_3受体表达的影响

目的：观察EA对CCI大鼠坐骨神经组织病理学及DRG P2X3受体表达的影响,探讨电针对神经组织学的影响及P2X3受体在电针镇痛效应中的作用。方法：将32只成年雄性SD大鼠,分为假模组、模型对照组、健侧EA组、患侧EA组,每组8只,模型对照组及EA组结扎坐骨神经造成CCI疼痛模型。各组于术前（0天）及术后3、57、1、01、2、14天分别测量大鼠患侧足MWT和TWL,EA组于术后第8天电针＂足三里＂-＂阳陵泉＂连续7天,每天1次。术后14天对坐骨神经标本行组织学观察,采用Estebe评分方法行组织学评分,免疫荧光组织化学检测患侧L5背根神经节中P2X3受体的表达情况。结果：与术前比较,CCI各组大鼠痛阈明显降低,出现痛觉过敏（P〈0.01）,而电针干预后EA组较CCI模型组痛阈明显增加（P〈0.05）但仍低于假模组。各组大鼠坐骨神经组织学观察无明显差异,各组评分差异无统计学意义（P〉0.05）。术后14天EA组较模型对照组患侧DRG L5中P2X3受体表达显著减少（P〈0.05）,并且患侧EA组较健侧EA组减少明显。结论：电针对坐骨神经压迫性损伤的镇痛效果可能是通过抑制大鼠DRG中P2X3受体的表达产生作用;患侧电针较健侧电针镇痛效果明显;电针后坐骨神经未见明显的病理组织学改变。

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.