右美托咪定对小鼠反复缺血再灌注脑损伤时NOD样受体蛋白3炎症小体表达的影响

Effects of dexmedetomidine on the expression of NOD-like receptor protein 3 inflammasomes in mice with repeated ischemia-reperfusion brain injury

目的探讨右美托咪定对小鼠反复缺血再灌注(IR)脑损伤时NOD样受体蛋白3(NLRP3)炎症小体表达的影响。方法选取清洁级健康雄性C57BL/6J小鼠27只作为研究对象,采用随机数字表法分为右美托咪定预先给药组(9只,D组)、IR组(9只)和假手术组(9只,S组)。D组小鼠于建模前30 min腹腔注射25μg/kg右美托咪定,同期IR组和S组注射等量0.9%氯化钠溶液,30 min后S组小鼠分离出双侧颈总动脉,但不夹闭,D组和IR组经夹闭双侧颈总动脉建立反复IR脑损伤模型。行水迷宫测试并在行为学测试完毕后2 h处死小鼠,取海马组织检测湿/干重比和总含水量;采用聚合酶链反应和蛋白质印迹法检测海马组织中NLRP3、凋亡相关斑点样蛋白(ASC)、半胱氨酸天冬氨酸蛋白酶1(Caspase-1)的mRNA和蛋白表达情况;采用酶联免疫吸附试验法检测海马组织中白细胞介素1β(IL-1β)和IL-18的表达量。结果IR组逃避潜伏期显著高于D组和S组[(27.6±6.2)s比(15.1±4.6)、(6.8±0.9)s],且D组逃避潜伏期显著高于S组,而S组穿越原平台次数显著高于D组和IR组[(11.0±2.3)次比(6.7±1.2)、(2.2±0.3)次],且D组穿越原平台次数显著高于IR组(均P<0.05)。IR组海马组织湿/干重比及总含水量显著高于D组和S组,且D组海马组织湿/干重比及总含水量显著高于S组(均P<0.05)。IR组NLRP3、Caspase-1和ASC的mRNA和蛋白表达均显著高于D组和S组,且D组均显著高于S组(均P<0.05)。IR组海马组织中IL-1β和IL-18表达量均显著高于D组和S组,且D组显著高于S组(均P<0.05)。结论IR脑损伤前30 min给小鼠注射右美托咪定,可抑制脑组织NLRP3炎症小体表达,进而减轻脑组织所受损伤。

Objective To investigate the effect of dexmedetomidine on the expression of NOD-like receptor protein 3(NLRP3)inflammasomes in mice with repeated ischemia-reperfusion(IR)brain injury.Methods Twenty-seven clean and healthy male C57 BL/6 J mice were selected.They were divided into dexmedetomidine pre-administration group(9 mice,group D),IR group(9 mice)and sham operation group(9 mice,group S)by random number table method.Mice in group D were given 25μg/kg dexmedetomidine intraperitoneal injection 30 min before modeling.At the same time,mice in IR group and group S were given the same amount of 0.9%sodium chloride solution intraperitoneal injection.After 30 min,mice in group S were isolated bilateral common carotid arteries,but did not clip them.Mice in group D and IR group were clipped bilateral common carotid arteries to establish repeated IR brain injury models.The water maze test was performed and the mice were sacrificed 2 h after the behavioral test.The wet/dry weight ratio and total water content were measured by taking part of hippocampus.The mRNA and protein expressions of NLRP3,apoptosis-associated speck-like protein(ASC)and cysteine aspartate specific protease 1(Caspase-1)in hippocampus were detected by polymerase chain reaction and western blotting.The enzyme-linked immunosorbent assay was used to detect the levels of interleukin-1β(IL-1β)and IL-18 in the hippocampus.Results The escape latency of IR group was significantly higher than that of group D and group S[(27.6±6.2)s vs(15.1±4.6),(6.8±0.9)s],and that of group D was significantly higher than that of group S;the number of crossings of the original platform of group S was significantly higher than that of group D and IR group[(11.0±2.3)times vs(6.7±1.2),(2.2±0.3)times],and that of group D was significantly higher than that of IR group(all P<0.05).The wet/dry weight ratio and total water content of hippocampus of IR group were significantly higher than that of group D and group S,and those of group D were significantly higher than those of group S(all P<0.05).The mRNA and protein expressions of NLRP3,Caspase-1 and ASC of IR group were significantly higher than those of group D and group S,and those of group D were significantly higher than those of group S(all P<0.05).The expression of IL-1βand IL-18 of IR group was significantly higher than those of group D and group S,and those of group D were significantly higher than those of group S(all P<0.05).Conclusion Injecting dexmedetomidine into mice 30 min in advance can inhibit the expression of NLRP3 inflammasomes in brain tissues,thereby reducing the damage to brain tissues.