富氢液对神经病理性痛大鼠脊髓神经细胞自噬的影响

Effect of hydrogen-rich saline on autophagy in spinal neurons of rats with neuropathic pain

目的评价富氢液对神经病理性痛大鼠脊髓神经细胞自噬的影响。方法清洁级雄性SD大鼠60只，8～10周龄，体重220～250g。采用随机数字表法分为3组（n=20）：假手术组（S组）、神经病理性痛组（NP组）和富氢液组（H组）。采用坐骨神经慢性压迫法制备大鼠神经病理性痛模型。H组术前腹腔注射富氢液5ml／kg，1次／d，连续7d，S组和NP组给予等量生理盐水。于术前1d（T0）、术后1、3、5和7d（T1-4）时测定机械缩足反应阈（MWT）和热缩足潜伏期（TWL），T7时测定痛阈后生理盐水心脏灌注，取脊髓L4-6节段，采用Western blot法检测自噬相关蛋白微管相关蛋白轻链3（LC3）Ⅱ、Beclin-1和p62的表达。结果与S组比较，NP组和H组T2-4时MWT降低，TWL缩短，T4时脊髓LC3Ⅱ、Beclin-1和p62表达上调（p〈0．05）；与NP组比较，H组T2-4时MWT升高，TWL延长，T4时脊髓LC311和Beclin-1表达上调，p62表达下调（P〈0．05）。结论富氢液减轻大鼠神经病理性痛的机制与诱导脊髓神经细胞自噬有关。

Objective To evaluate the effect of hydrogen-rich saline on autophagy in the spinal neurons of rats with neuropathic pain. Methods Sixty pathogen-free male Sprague-Dawley rats, aged 8- 10 weeks, weighing 220-250 g, were randomly assigned into 3 groups （n = 20 each） using a random num- ber table： sham operation group （ S group） , neuropathic pain group （ NP group） , and hydrogen-rich saline group （ H group）. Neuropathie pain was produced by chronic constriction injury of the sciatic nerve in the rats anesthetized with chloral hydrate. Hydrogen-rich saline 5 ml/kg was injected intraperitoneally once a day for 7 consecutive days in group H, while the equal volume of normal saline was given instead in S and NP groups. The mechanical paw withdrawal threshold （MWT） and thermal paw withdrawal latency （TWL） were measured at 1 day before operation （T0） and 1, 3, 5 and 7 days after operation （T1-4）. The animals were sacrificed after measurement of pain threshold at day 7 after operation. L4-6 segments of the spinal cord were harvested to detect the expression of autophagy-related proteins microtubule-assoeiated protein 1 light chain 3 II （LC3 II ） , Beclin-i and p62 by Western blot. Results Compared with group S, the MWT was significantly decreased, and the TWL was significantly shortened at T2-4, and the expression of LC3 II , Beclin-1 and p62 was significantly up-regulated at T4 in NP and H groups （P〈0.05）. Compared with group NP, the MWT was significantly increased, and the TWL was significantly prolonged at T2-4 , and the expression of LC3 II and Beclin-1 was significantly up-regulated, and the expression of p62 was significantly down-regulated at T4 in group H （P 〈0.05）. Conclusion The mechanism by which hydrogen-rich saline reduces neuropathic pain is related to induction of autophagy in the spinal neurons of rats.