麝香酮对脓毒血症小鼠心肌损伤的作用机制研究

Effect of Muscone on Myocardial Injury in Mice with Sepsis

目的:探讨麝香酮在脓毒血症小鼠心肌损伤中的作用及可能机制。方法:将36只雄性8~10周龄C57BL/6小鼠,随机分为对照组、脂多糖(LPS)组及LPS+麝香酮组,每组12只。LPS组和LPS+麝香酮组小鼠腹腔注射LPS 5 mg/kg以构建脓毒血症心肌损伤模型,LPS+麝香酮组小鼠于LPS注射前7 d开始,每日09:00给予2 mg/kg的麝香酮灌胃处理。对比分析各组小鼠心脏左室射血分数(LVEF)、左室短轴缩短率(LVFS)及心率;实时荧光定量逆转录聚合酶链式反应法(qRT-PCR)测定心肌组织中肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)和高迁移率族蛋白B1(HMGB1)的mRNA表达;免疫组织化学染色标记心肌组织中CD 45阳性细胞浸润水平;同时检测小鼠肌酸激酶(CK-MB)、乳酸脱氢酶(LDH)及天门冬氨酸氨基转移酶(AST)的含量以评估心肌损伤状况;采用蛋白免疫印迹(Western Blot)法检测心肌组织中NOD样受体热蛋白结构域相关蛋白3(NLRP3)、凋亡相关斑点样蛋白(ASC)和白细胞介素-18(IL-18)蛋白表达情况。结果:与对照组比较,LPS组小鼠LVEF及LVFS明显降低,TNF-α、IL-1β、HMGB1 mRNA表达量升高,CD 45阳性细胞百分比升高,血清CK-MB、LDH及AST水平升高,NLRP3、ASC、IL-18蛋白表达量升高,差异均有统计学意义(P<0.05)。与LPS组比较,LPS+麝香酮组LVEF及LVFS明显升高,TNF-α、IL-1β、HMGB1 mRNA表达量降低,CD 45阳性细胞百分比降低,血清CK-MB、LDH及AST水平降低,NLRP3、ASC、IL-18蛋白表达量降低,差异均有统计学意义(P<0.05)。结论:麝香酮可能通过调节NLRP3炎性小体介导的心肌细胞焦亡反应减轻脓毒血症小鼠心肌炎症及损伤。

Objective:To explore the effect of muscone on myocardial injury in mice with sepsis and its possible mechanism.Methods:Thirty-six male C57BL/6 mice aged 8 to 10 weeks were randomly divided into control group,lipopolysaccharide(LPS)group and LPS+muscone group,with 12 mice in each group.Mice in LPS group and LPS+musketone group were intraperitoneally injected with LPS 5 mg/kg to construct myocardial injury model of sepsis.Mice in LPS+musketone group were given 2 mg/kg musketone by intragastric administration before LPS injection.Left ventricular ejection fraction(LVEF),left ventricular short axis shortening rate(LVFS),and heart rate were compared.Real-time fluorescence quantitative reverse transcription polymerase chain reaction(qRT-PCR)was used to detect the mRNA expression of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),and high mobility group protein B1(HMGB1)in myocardial tissue.The infiltration level of CD 45 leukocyte infiltration in myocardial tissue was marked by immunohistochemical staining.The contents of creatine kinase(CK-MB),lactate dehydrogenase(LDH),and aspartate aminotransferase(AST)in mice were detected to evaluate myocardial injury.The expression of NOD-like receptor heat protein domain associated protein 3(NLRP3),apoptosis-associated specular protein(ASC),and interleukin-18(IL-18)in myocardial tissue were detected by Western Blot.Results:Compared with the control group,LVEF and LVFS in LPS group significantly decreased,mRNA expression levels of TNF-α,IL-1βand HMGB1 increased,percentage of CD 45 leukocyte infiltration increased,serum levels of CK-MB,LDH and AST increased,and NLRP3,ASC and IL-18 protein expression levels increased(P<0.05).Compared with LPS group,LVEF and LVFS in LPS+muscosterone group significantly increased,the mRNA expression levels of TNF-α,IL-1βand HMGB1 decreased,the percentage of CD 45 leukocyte infiltration decreased,the levels of serum CK-MB,LDH and AST decreased,and the protein expression levels of NLRP3,ASC,and IL-18 decreased(P<0.05).Conclusion:Muscosterone may reduce myocardial inflammation and injury in mice with sepsis by regulating NLRP3 inflammator-mediated pyroptosis of myocardium.