糖尿病神经病理性疼痛大鼠坐骨神经阻滞时效改变及相关机制

Prolonged sciatic nerve block durations in painful diabetic neuropathy rats and potential mechanisms

目的比较糖尿病神经病理性疼痛(PDN)大鼠与对照大鼠坐骨神经阻滞时效差异,并初步探讨PDN大鼠阻滞时效改变的相关机制。方法建立PDN大鼠模型:5只作为未干预对照组,另10只于左侧坐骨神经分别应用布比卡因(n=5)、罗哌卡因(n=5)进行神经阻滞,并于右侧坐骨神经旁注射0.9%氯化钠溶液作为对照。再取15只对照大鼠依同样方法处理。比较不同组别大鼠感觉和运动阻滞时间。神经阻滞后第2天取双侧坐骨神经染色,显微镜下观察、计数神经元损伤类型及数目。结果在相同阻滞条件下,PDN大鼠感觉和运动阻滞持续时间均显著长于对照大鼠(P<0.05)。PDN大鼠坐骨神经纤维损伤比例高于对照大鼠(P<0.05);施行神经阻滞后,PDN大鼠神经纤维损伤比例显著提高(P<0.05)。结论 PDN大鼠可能存在神经损伤易感性,并与糖尿病病变所致的神经纤维损伤存在累积效应,这可能是PDN大鼠阻滞时效显著延长的潜在机制。

Objective To compare sciatic nerve block durations between painful diabetic neuropathy （PDN） rats and nondiabetic ones,and to explore the potential mechanisms.Methods PDN model was established,10 of which were injected normal saline （NS） adjacent to the right sciatic nerves and ropivacaine（n =5）/ bupivacaine（n =5） adjacent to the left sciatic nerves.Another 15 control rats were treated in the same way as above.Sciatic nerves were carefully removed 2 days after the injection for HE staining.Results Both local anesthetic solutions produced significantly longer mean durations of sensory nerve block and motor nerve block in PDN rats than in nondiabetic rats （P ＜ 0.05）.Histological study revealed a significantly higher nerve damage rate in PDN rats than in nondiabetic ones （P ＜ 0.05）.Besides,nerve damage rates were significantly increased after the sciatic nerve block in PDN rats （P ＜ 0.05）.Conclusions Susceptibility to nerve injury may exist in PDN rats,which,along with the diabetic neuropathy per se,may constitute the potential mechanism of block duration prolongation.