褪黑素通过抑制NLRP3活化减轻蛛网膜下腔出血大鼠早期脑损伤

Melatonin alleviates early brain injury in rats with subarachnoid hemorrhage by inhibiting NLRP3 activation

目的:研究外源性褪黑素对蛛网膜下腔出血大鼠(SAH)早期脑损伤(EBI)的影响及分子机制。方法:60只成年雄性SD大鼠随机分为假手术组(sham)、SAH组和褪黑素治疗组(SAH+Melatonin),用注射自体血液的方法制备SAH大鼠模型,腹腔注射方法给予褪黑素进行治疗。通过检测大鼠脑的含水量评估脑水肿程度,利用real time RT-PCR方法检测大鼠脑组织中IL-1β、IL-6和单核细胞趋化蛋白1(MCP-1) mRNA的表达,利用免疫组织化学染色法观察大脑皮层中核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)的表达,利用Western Blot方法检测NLRP3和cleaved caspase-1的表达。结果:SAH大鼠皮层发生水肿,IL-1β、IL-6和MCP-1 mRNA的表达增加,NLRP3和cleaved caspase-1蛋白的表达增加。褪黑素能减轻SAH大鼠脑水肿,抑制皮层中IL-1β、IL-6和MCP-1 mRNA的表达,下调皮层NLRP3和cleaved caspase-1蛋白的表达。结论:褪黑素通过抑制NLRP3活化减轻SAH大鼠的早期脑损伤。

Objective:To investigate the effects of exogenous melatonin on early brain injury(EBI)in rats with subarachnoid hemorrhage(SAH)and its molecular mechanism.Methods:Sixty adult male SD rats were randomly divided into sham operation group(Sham),SAH group(SAH)and melatonin treatment group(SAH+Melatonin).SAH rat model was prepared by injecting autologous blood,and melatonin was injected intraperitoneally.The cerebral water content of rats was detected to assess the degree of cerebral edema.The expressions of IL-1β,IL-6,and monocyte chemotactic protein 1(MCP-1)mRNA in brain tissues were detected by real time RT-PCR.Immunohistochemical staining was used to detect the expression of NLRP3 in cerebral cortex of rats.Western Blot was used to detect the expression of NLRP3 and cleaved caspase-1 in cerebral cortex of rats.Results:SAH caused cerebral edema,increased the expression of IL-1β,IL-6,and MCP-1 mRNA,as well as the expression of NLRP3 and cleaved caspase-1 in cortex of rats.Melatonin treatment alleviated cerebral edema,down-regulated the expression of IL-1β,IL-6,and MCP-1 mRNA,as well as the expression of NLRP3 and cleaved caspase-1 in cortex of SAH rats.Conclusion:Melatonin alleviates EBI in cortex of SAH rats by inhibiting NLRP3 activation.