细胞焦亡及炎性小体在大鼠术后认知功能障碍中的作用

Role of pyroptosis and inflammasome in postoperative cognitive dysfunction in rats

目的探讨细胞焦亡及炎性小体在大鼠术后认知功能障碍(POCD)中的作用。方法 24只雄性SD大鼠,体重260~290 g,随机分成4组:NS组、POCD 2W组、POCD 4W组、POCD 6W组,每组6只。采用海马区注射Aβ1-40法制备大鼠POCD模型,NS组大鼠注射等量的生理盐水进行对照。分别于术后2、4、6周行水迷宫行为学测试后处死各组大鼠。采用Western blot法检测各组大鼠海马内半胱氨酸天冬氨酸蛋白酶1(caspase-1)和凋亡相关斑点样蛋白(ASC)表达情况,采用ELISA法测定大鼠海马IL-1β和IL-18的含量,采用吖啶橙/溴乙锭荧光比色测定海马内细胞焦亡情况。结果与NS组相比,POCD 2W组大鼠上台前路程和逃避潜伏期变化差异均无统计学意义(P>0.05),而POCD 4W组和POCD 6W组大鼠上台前路程和逃避潜伏期均延长(P<0.05);与NS组和POCD 2W组相比,POCD 4W组和POCD 6W组大鼠海马内ASC、IL-1β和IL-18表达显著增强(P<0.05)。与NS组、POCD 2W组和POCD 4W组相比,POCD 6W组大鼠海马内caspase-1表达增强,OD值升高(P<0.05)。结论大鼠术后认知功能障碍形成的部分机制可能与海马内炎性小体激活后所致的细胞焦亡有关。

Objective To investigate the role of pyroptosis and inflammasome in postoperative cognitive dysfunction（ POCD） in rats. Methods Totally 24 male SD rats,weighting 260- 290 g,were randomly divided into 4 groups（ n = 6） ： NS group,POCD 2 W group,POCD 4 W group and POCD 6 W group. POCD model was prepared with injection of Aβ1-40 into the hippocampus,while NS group was given the same amount of saline instead. Rats of each group were sacrificed after morris water maze behavior examination in postoperative 2 weeks,4 weeks and 6 weeks. The Western bolt was used to measure caspase-1 and apoptosis associated speck-like protein（ ASC） in rat hippocampus of each group,while ELISA method was used to evaluate the contents of IL-1β and IL-18 in rat hippocampus,and ethidium bromide was used to determine the pyroptosis of hippocampus. Results Compared with NS group,there was no significant difference in POCD 2 W rats in pre-platform course or escape latency（ P〉0. 05）,and pre-platform course and escape latency of rats in POCD 4 W group and POCD 6 W group were both prolonged（ P〈0. 05）. Compared with NS group and POCD 2 W group,the expression of ASC,IL-1 and IL-18 was significantly enhanced in the hippocampus of POCD 4 W group and POCD 6 W group（ P〈0. 05）. Compared to NS group,the POCD 2 W group and the POCD 4 W group,caspase-1 expression was enhanced in the hippocampus in the POCD 6 W group,and OD value was increased（ P〈0. 05）. Conclusion Some mechanisms of postoperative cognitive dysfunction in rats may be related to the pyroptosis induced by the activation of inflammasome.