术前给予巴氯酚延迟坐骨神经松结扎神经病理痛的形成

目的研究术前鞘内注射GABAB受体激动剂巴氯酚(Bac)对慢性神经病理痛大鼠痛阈的影响,探讨脊髓GABA能系统在神经病理痛调节中的作用。方法建立慢性坐骨神经结扎损伤模型(CCI),SD大鼠32只随机分成4组:假手术组,大鼠左侧坐骨神经分离,但不结扎,术前鞘内注射生理盐水10μL;神经结扎组,大鼠左侧坐骨神经松结扎,术前鞘内注射生理盐水10μL;Bac 1组,大鼠左侧坐骨神经松结扎前10 min,鞘内注射Bac 0.03μg;Bac 2组,大鼠左侧坐骨神经松结扎前10min,鞘内注射Bac 0.3μg。术后第1、3、5、7、10、14天测大鼠机械刺激缩足反射阈值(MWT)和热刺激缩足反射潜伏期(TWL)以及运动功能。结果术后第1~14天神经结扎组大鼠MWT和TWL较假手术组大鼠明显降低(P<0.05);术前给Bac 0.3μg的坐骨神经结扎大鼠与术前给生理盐水的坐骨神经结扎大鼠比较,术后第1~5天MWT和TWL明显升高(P<0.05)。结论坐骨神经结扎前鞘内注射Bac 0.3μg可延缓大鼠神经病理性疼痛的形成。

Preemptive Intrathecal Injection of Baclofen Delayed Neuropathic Pain Induced by Chronic Constriction Injury on Rats

Objective To investigate the effect of preemptive intrathecal injection of baclofen,a GABAB receptor agonist,on the development of neuropathic pain induced by chronic constriction injury in rats.Methods Sprague-Dawley(SD) rats were used and chronic constriction injury was induced by loosely ligating the left sciatic nerve of rats.Mechanical withdrawal threshold(MWT) and thermal withdrawl latency(TWL) were determined using von Frey filaments and radiation apparatus respectively.Thirty-two rats were randomly divided into four groups(n=8): sham group,left sciatic nerves were exposed without ligation and 10 μL of normal saline was intrathecally injected 10 min before operation;CCI group,left sciatic nerve were exposed and loosely ligated and 10 μL of normal saline was intrathecally injected at 10 min before operation;Bac group 1 and 2,0.03 μg or 0.3 μg baclofen was intrathecally injected before left sciatic nerve was ligated respectively.MWT and TWL were measured on days 1,3,5,7,10,14 after operation.Results Compared with the sham group,MWTs of CCI group were significantly lower from day 1 to day 14 after operation(P<0.05);TWLs of CCI group were significantly lower than those in the sham group from day 1 to day 14 after operation(P<0.05).MWTs of rats in Bac group 2 were significently higher than those in CCI group from day 1 to day 5 after operation(P<0.05);TWLs of rats in Bac group 2 were higher than those in sciatic nerve ligation group from day 1 to day 5 after operation(P<0.05).Conclusions Preemptive intrathecal injection of baclofen can delay the development of neuropathic pain induced by chronic constriction injury in rats.