星状神经节阻滞对老龄大鼠术后认知功能的影响

Effect of stellate ganglion block on postoperative cognitive function in aged rats

目的：评价星状神经节阻滞对老龄大鼠术后认知功能的影响以及这种影响是否与海马tau蛋白磷酸化水平有关。方法雄性SD大鼠72只。采用随机数字表法，将其随机分为3组（n=24）：正常对照组（C组）、手术组（O组）和星状神经节阻滞＋手术组（SGB组）。C、O组仅暴露右颈交感神经干但不阻滞，SGB组注射0.25%布比卡因0.15 ml行右侧SGB，给药结束后15 min时O、SGB组行剖腹探查术，手术时间30 min。C组不做任何处理。于手术后1 d（T1）、3 d（T2）、7 d（T3）每组取8只大鼠进行水迷宫实验，记录逃避潜伏期和穿越平台次数以及取海马组织，HE染色光镜下观察病理学结果以及免疫组化染色法检测海马tau蛋白磷酸化的表达水平。结果与C组比较，O、SGB组术后T1-T3时逃避潜伏期延长，穿越平台次数减少（P＜0.05），海马组织磷酸化tau蛋白表达上调（P＜0.01）。SGB组T3时逃避潜伏期,海马组织磷酸化tau蛋白表达与C组无明显差异（P＞0.05）；与O组比较，SGB组术后T1-T3时逃避潜伏期缩短，穿越平台次数增加，海马组织磷酸化tau蛋白表达下调（P＜0.05或P＜0.01）；SGB组T1-T3时海马神经元数量明显多于O组。结论星状神经节阻滞可改善老龄大鼠术后认知功能，其机制可能与抑制海马组织磷酸化tau蛋白表达有关。

Objective To investigate the effect of stellate ganglion block （SGB） on postoperative cognitive function and the relationship with phosphorylation levels of tau protein in aged rats. Methods Seventy-two male Sprague-Dawley rats, were randomly divided into 3 groups （n=24 each）： control group （group C）, operation group （group O）, and SGB＋ operation group （group SGB）. Group C and Group O just exposed the right cervical sympathetic trunk, but not blocked. Group SGB received right SGB with 0.25% bupivacaine 0.15 ml, Groups O, SGB underwent 30 min of exploratory laparotomy starting from 15 min after the end of administration. Morris water-maze test was performed at 1 d （T1）, 3 d （T2）, 7 d （T3） after operation in 8 rats chosen from each group. The escape latency and frequency of crossing the original platform were recorded. Then sacrificed and the hippocampi were removed for microscopic examination and phosphorylation levels of tau protein. Results Compared with group C, the escape latency was significantly prolonged on T1-T3 after operation, the frequency of crossing the original platform was decreased （P〈0.05） and the phosphorylation levels of tau protein was expressed higher in groups O and SGB. The escape latency and the phosphorylation levels of tau protein at T3 in group SGB had no significant difference with group C. Compared with group O, the escape latency was significantly shortened, the frequency of crossing the original platform was increased, and phosphorylation levels of tau protein was expressed obviously lower at T1-T3 after operation in group SGB （P〈0.05 or P〈0.01）. The number of hippocampal neurons was significantly larger at T1-T3 in group SGB than in group O. Conclusion SGB can improve the postoperative cognitive function in aged rats, and depress over phosphorylation of tau protein may be one of its mechanisms.