高压氧通过抑制NLRP3炎症小体活性治疗大鼠急性CO中毒迟发性脑病的研究

Hyperbaric oxygen treatment on DEACMP in rats by inhibiting NLRP3 inflammasome activation

目的探讨高压氧(HBO)处理对急性一氧化碳中毒迟发性脑病(DEACMP)模型大鼠脑组织中NOD样受体蛋白3(NLRP3)炎症小体的调控作用及其相关机制。方法健康成年SPF级雄性SD大鼠90只,按照随机数字表法分为3组:假手术对照组(Sham组)、DEACMP组、HBO组,每组30只。DEACMP组和HBO组大鼠依照静态吸入染毒法建立DEACMP模型。每组大鼠又分为染毒前及染毒后3、7、14、21 d 5个亚组,每个亚组6只。采用Morris水迷宫实验评估各组大鼠染毒前后的学习和空间记忆能力。利用ELISA、Western blotting实验分别检测各组大鼠血清白细胞介素(IL)-1β、IL-18水平及脑组织中NLRP3、衔接蛋白凋亡相关斑点样蛋白(ASC)、黑色素瘤缺乏因子2(AIM2)以及caspase-1蛋白的表达水平;TUNEL实验检测大鼠海马组织神经细胞的凋亡情况。结果与Sham组比较,DEACMP组和HBO组大鼠在不同时间点的逃避潜伏期明显延长(P<0.05),平台象限活动时间明显缩短(P<0.05),血清IL-1β和IL-18水平明显降低(P<0.05)。与DEACMP组比较,HBO组逃避潜伏期和平台象限活动时间从染毒后第7天开始明显改善(P<0.05),血清IL-1β和IL-18水平明显降低(P<0.05)。与Sham组比较,DEACMP组大鼠脑组织中NLRP3、ASC、AIM2以及caspase-1表达水平和海马组织神经细胞凋亡指数均明显提高(P<0.05);与DEACMP组比较,HBO组上述蛋白表达和细胞凋亡水平均明显提高(P<0.05)。结论HBO通过阻断NLRP3炎症小体活化抑制DEACMP引起的炎症反应,从而减轻一氧化碳中毒造成的脑组织损伤。

Objective To investigate the regulating effect and its mechanism of action of hyperbaric oxygen(HBO)therapy on delayed encephalopathy after acute carbon monoxide poisoning(DEACMP)by regulating inflammasome of NOD-like receptor pyxin domain-related protein 3(NLRP3)in rat model’s brain tissue.Methods A total of 90 SD rats were randomly divided into three groups:sham group,DEACMP group,and HBO group,with 30 rats in each group.Within the DEACMP group and the HBO group,the DEACMP model was established by static inhalation of poisoning.The rats in each group were divided into five subgroups,i.e.,before exposure,and 3,7,14,and 21 days after exposure,with six rats in each subgroup.Morris water maze test was used to evaluate the learning and spatial memory ability of rats in each group before and 3,7,14,and 21 days after exposure.The IL-1βand IL-18 levels were detected by ELISA;NLRP3,ASC,AIM2,and Caspase-1 were detected by Western blotting;the apoptosis of neurons in rat hippocampus was detected by TUNEL.Results Compared with the sham group at each time point,the escape latencies(EL)of the DEACMP group and the HBO group were significantly prolonged(P<0.05),the activated time of the located quadrant platform(TP)was significantly shortened(P<0.05),and serum levels of IL-1βand IL-18 decreased significantly(P<0.05).Compared with the DEACMP group,the EL and TP in the HBO group improved significantly from day 7 after exposure(P<0.05),while serum levels of IL-1βand IL-18 were significantly reduced(P<0.05).The levels of NLRP3,ASC,AIM2,and Caspase-1 protein in brain tissues and neuronal apoptosis in hippocampus in the DEACMP group were significantly higher than those in the sham group(P<0.05);while the levels of NLRP3,ASC,AIM2,and Caspase-1 protein in brain tissues and apoptosis in the HBO group were significantly higher than those in the DEACMP group(P<0.05).Conclusion HBO can inhibit the inflammatory reaction of nerve cells induced by DEACMP through blocking the activation of NLRP3 inflammasome,thus alleviating the brain tissue damage caused by carbon monoxide poisoning.