手术创伤对老龄大鼠认知功能及海马ApoE表达影响

EFFECTS OF SURGICAL TRAUMA ON COGNITIVE FUNCTION AND EXPRESSION OF APOE IN HIPPOCAMPUS OF AGED RATS

目的探讨手术创伤对老龄大鼠认知功能及海马CAl区载脂蛋白E（ApoE）表达的影响。方法将36只Wistar大鼠按随机数字表法分为3组，每组12只。正常对照组（c组）腹腔注射生理盐水；麻醉组（A组）腹腔注射戊巴比妥钠麻醉，不进行手术；手术创伤组（S组）腹腔注射戊巴比妥钠麻醉，待翻正反射消失后行脾切除手术。各组于术前1～5d、术后1～4d进行Morris水迷宫实验，测定认知功能。测试结束后立即处死大鼠，取脑组织，采用免疫组织化学法，检测海马CAl区ApoE的表达。结果与术前比较，A组术后1d、S组术后1～3d逃避潜伏期延长（F=46．108、82．003，q=2．771～14．627，Pd0．05）；与C组比较，A组术后1d、S组术后1～3d逃避潜伏期延长（F=26．930～119．360，q=6．578～15．450，P〈0．05）。与C组比较，S组术后4d原平台象限停留时间缩短（F=32．021，q=7．209，P〈0．05），穿越原平台次数减少（F=16．026，q=5．170，P〈0．05），海马CAl区ApoE免疫反应阳性细胞增多（F=9．148，q=4．117，Pd0．05）。结论手术创伤可导致老龄大鼠认知功能减退，其机制可能与海马中ApoE表达上调有关。

Objective To explore the effects of surgical trauma on cognitive function and expression of Apolipoprotein E （ApoE） in the hippocampal CA1 area of aged rats. Methods Thirty-six Wistar rats were evenly randomized to three groups as control group （Group C）, anesthesia group （Group A） and surgical trauma group （Group S）. The rats in the group C were given intraperitoneal injection of normal saline, those in group A were anesthetized using intraperitoneal injection of pentobarbital sodium, no operation was performed, for those in group S, intraperitoneal pentobarbital-sodium-anesthesia was given and a splenectomy performed. Morris water maze experiment was carried out to assay cognition function 1--5 days before and 1--4 days after surgery. The rats were sacrificed upon completion of the test, the brain tissues were taken for detection of ApoE expression in hipp- ocampal CA1 area using immunohistochemical method. Results Compared with pre-operatlon, the escape latent period was in creased one day after surgery in group A, and one to three days in group S （F=46.108,82.003;q=2.771--14.627 P〈0.05）; Compared with group C, the escape latent period in group A increased one day after surgery, and that in group S increased one to three days after （F = 26.930 -- 119.360, q = 6.578 -- 15.450, P〈 0.05 ）. A comparison between group C and group S showed that, four days after surgery, the period of rat staying in the pristine quadrant in group S shortened （F=32.021,q= 7. 209,P〈0.05）, the number of times traversing terrace decreased （F = 16.026, q =5.170, P〈0.05）, and the number of positive ApoE immunoreac- tire cells in hippocampal CA1 area increased （F=9.148,q=4.117,P〈0.05）. Conclusion Surgical trauma may result in cogni- tive dysfunction in aged rats, its mechanism is likely to be related with up-regulation of ApoE expression in hippocampus. EKEY WORDS~ surgical procedures, operative; wounds and injuries; cognition; hippocampus; apolipoproteins E; rats