神经病理性痛大鼠内侧额叶前皮质GABAAα1受体表达的变化

Changes in expression of GABAAal receptors in medial prefrontal cortex in a rat model of neuropathic pain

目的 评价神经病理性痛大鼠内侧额叶前皮质卜氨基丁酸Aa1亚型（GABAAal）受体表达的变化。方法成年雄性Wistar大鼠9只，体重200～210g，采用随机数字表法，将其随机分为3组（n=3）：对照组（C组）、假手术组（S组）和神经病理性痛组（P组）。P组采用坐骨神经慢性压迫法制备大鼠神经病理性痛模型；S组只暴露坐骨神经，而不结扎。于术前1d和术后1、4、7、10、14d时，测定机械痛阈和热痛阚。痛阈测定结束后，处死大鼠，取内侧额叶前皮质，采用Westernblot法检测GABA。受体的表达。结果与C组和S组比较，P组术后各时点机械痛阈和热痛阈降低，内侧额叶前皮质GABA。受体表达上调（P〈0．01）；C组和S组间机械痛阈、热痛阈和内侧额叶前皮质GABA。受体表达比较差异无统计学意义（P〉0．05）。结论内侧额叶前皮质GABA。受体表达上调可能参与了大鼠神经病理性痛的形成与维持。

Objective To investigate the changes in the expression of GABAAal receptors in medial prefrontal cortex （mPFC） in a rat model of neuropathic pain. Methods Nine male Wistar rats weighing 200-210 g were randomly divided into 3 groups （ n = 3 each） ： control group （group C）, sham operation group （group S） and ncuropathic pain group （group P）. Neuropathic pain was induced by chronic constrictive injury. The right sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1 mm intervals with 3-0 chromic catgut. In group S, the fight sciatic nerve was exposed but not hgated. The thermal and mechanical pain threshold was measured at 1 d before and 1, 4, 7, 10 and 14 d after operation. The animals were then sacrificed and the mPFC was removed. The expression of GABAAal receptors in mPFC was determined by Western blot. Results Compared with C and S groups, thermal and mechanical pain threshold were significantly decreased and the expression of GABAAo~ receptors was up-regulated in group P （P 〈 0.01 ）. There was no significant difference was in the thermal and mechanical pain threshold and expression of GABAAal receptors between C and S groups （P 〉 0.05）. Conclusion Up-regulation of GABAAal receptor expression in mPFC may be involved in the development and maintenance of neuropathic pain in rats.