脂联素通过减少NLRP3炎症体的表达来减轻脑出血大鼠模型认知障碍的机制

Mechanism of adiponectin reducing the expression of NLRP3 inflammasome to reduce cognitive impairment in rat models of cerebral hemorrhage

目的探究脂联素通过减少NLRP3炎症体的表达来减轻脑出血大鼠模型认知障碍的机制。方法选择8~10周36只成年雄性SD大鼠,根据随机数字表法均分为3组:对照组(n=12),脑出血组(n=12)和脂联素治疗组(n=12)。对照组实施假手术+空载体干预,脑出血组实施脑出血+空载体干预,脂联素治疗组实施脑出血+脂联素慢病毒载体干预。在脑出血前14 d通过脑室内注射脂联素。通过被动回避测试和莫里斯水迷宫测试评估其学习和记忆能力。通过湿重/干重法评估脑含水量,通过EB染料外渗评估血脑屏障(BBB)通透性。实时荧光定量聚合酶链式反应检测NLRP3、白细胞介素(IL)-1β、IL-18 mRNA的水平。采用蛋白质印迹法测定核因子(NF)-κB、Toll样受体4(TLR4)和核因子-E2相关因子2(Nrf2)蛋白水平。结果与对照组相比,脑出血组大鼠进入暗室的频率、第3~5天的逃避潜伏期和路径长度、脑含水量和BBB通透性、NLRP3、IL-1β和IL-18 mRNA水平以及NF-κB和TLR4蛋白水平均显著增加,而其进入暗室的潜伏期和Nrf2蛋白质水平则显著减少,差异均有统计学意义(P<0.05);与脑出血组相比,大鼠进入暗室的频率、第3~5天的逃避潜伏期和路径长度、脑含水量和BBB通透性、NLRP3、IL-1β和IL-18 mRNA水平以及NF-κB和TLR4蛋白水平均显著减少,而其进入暗室的潜伏期和Nrf2蛋白水平则显著增加,差异均有统计学意义(P<0.05)。结论脂联素通过减少NLRP3炎症体的表达,激活Nrf2表达,下调TLR4/NF-κB信号传导,降低脑出血周围的脑水肿和BBB功能障碍,从而减轻脑出血大鼠模型认知障碍。

Objective To explore the mechanism of adiponectin reducing the expression of NLRP3 inflammasome to reduce cognitive impairment in rat models of cerebral hemorrhage.Methods Adult 36 male SD rats aged 8~10 weeks were divided into three groups according to the random digital table method:control group(n=12),cerebral hemorrhage group(n=12)and adiponectin treatment group(n=12).The control group was treated with sham operation and no-load body intervention;The cerebral hemorrhage group was treated with no-load body intervention;The treatment group of adiponectin was treated with cerebral hemorrhage and adiponectin slow virus vector intervention.Adiponectin was injected into the ventricles 14 days before cerebral hemorrhage.The learning and memory abilities were evaluated by passive avoidance test and Morris water maze test.The water content of brain was evaluated by wet weight/dry weight method,and the permeability of BBB was evaluated by EB dye infiltration.The levels of NLRP3,interleukin(IL)-1β,and IL-18 mRNA were detected using real-time fluorescent quantitative polymerase chain reaction.The protein levels of nuclear factor(NF)-κB,Toll-like receptor 4(TLR4)and nuclearfactor erythroidderived 2-like 2(Nrf2)were detected by Western blotting.Results Compared with the control group,the rats in the cerebral hemorrhage group entered the dark room frequency,escape latency and path length on day 3-5,brain water content and BBB permeability,NLRP3,IL-1β,IL-18 mRNA levels,and expression levels of NF-κB,TLR4 protein increased significantly,and the latency of entering the darkroom and Nrf2 protein level were significantly reduced,the differences were statistically significant(P<0.05).Compared with the cerebral hemorrhage group,the frequency of rats entering the dark chamber,the escape latency and path length on the third to fifth day,the water content and BBB permeability,NLRP3,IL-1β,IL-18 mRNA levels and the expression level of NF-κB,TLR4 protein decreased significantly,but the latency of entering the darkroom and Nrf2 protein level were significantly increased,the differences were statistically significant(P<0.05).Conclusion Adiponectin reduces the expression of NLRP3 inflammasome,activates the expression of Nrf2,down-regulates TLR4/NF-κB signaling,reduces brain edema around cerebral hemorrhage and BBB dysfunction,thereby reducing cognitive impairment in rat models of cerebral hemorrhage.