炎症小体Nlrp3通路激活在尿毒症心肌病模型小鼠左心室重构的作用

Effect of Nlrp3 inflammasomes pathway activation on left ventricular remodeling in uremic cardiomyopathy model rats

目的探讨Nlrp3炎症小体通路激活与尿毒症心肌病小鼠左心室重构的关系及可能机制。方法将20只小鼠随机分为假手术组和模型组。模型组予5/6肾脏切除术。两组小鼠术后第8周行心脏超声检查,检测血肌酐(Scr)、血尿素氮(BUN)、血浆硫酸吲哚酚(indoxyl sulfate,IS)水平,心肌组织ANP、BNP、Nlrp3、Pro-caspase1、IL-1β和p-P65蛋白表达。培养小鼠巨噬细胞RAW264.7,分为对照组及IS组,检测两组细胞Nlrp3、Pro-caspase1和IL-1β蛋白表达。结果与假手术组相比,模型组小鼠Scr、BUN和IS水平均升高(P<0.05);左心室前壁舒张末期厚度(LVAWd)和左心室后壁舒张末期厚度(LVPWd)增厚,射血分数(EF)和短轴缩短率(FS)降低。更进一步,左心室等容舒张时间和E/A上升,LVFS/MPI下降。HE染色可见心肌细胞肥大。模型组心肌组织ANP、BNP、Nlrp3、Pro-caspase1、IL-1β和p-P65蛋白表达均上调。IS刺激小鼠巨噬细胞Nlrp3、Pro-caspase1和IL-1β蛋白表达均上调。以上结果均具有统计学意义。结论尿毒症心肌病小鼠左心室肥厚与血浆IS水平上调密切相关,可能与NF-κB信号通路激活炎症小体Nlrp3高度相关。

Objective To investigate the relationship between activation of NLRP3 inflammasome pathway and left ventricular remodeling in uremic cardiomyopathy rats.Methods 20 C57BL/6J mouse were randomly divided into sham operation and model groups and 5/6 nephrectomy was performed in the model group. Both groups underwent laparotomy with no kidney removal. Cardiac echocardiography was performed in all rats 8 weeks after rat model establishment. Serum creatinine,blood urea nitrogen,plasma indoxyl sulfate(IS)levels,and expression of ANP,BNP,Nlrp3,Pro-caspase1,IL-1β and p-P65 protein in myocardial tissue were measured in the two groups.Cultured rats macrophages RAW264.7 were divided into control group and indoxyl sulfate(IS)group and protein expression of Nlrp3,Pro-caspase1 and IL-1β were detected in different treatment groups.Results Compared with the sham operation group,the levels of serum creatinine(Scr),urea nitrogen(BUN),and plasma IS were increased in the model group(P < 0.05);cardiac ultrasound revealed that left ventricular anterior wall end-diastolic thickness(LVAWd)and left ventricular posterior wall end-diastolic thickness(LVPWd)were significantly thickened,ejection fraction(EF)and fractional shortening(FS)were significantly decreased(P < 0.05). Furthermore,the left ventricular isovolumic relaxation time and the E/A in the surgical group were significantly increased(P < 0.05)and the LVFS/MPI decreased significantly(P < 0.05). HE staining revealed cardiomyocytes hypertrophy. The expression of ANP,BNP,Nlrp3,Pro-caspase1,IL-1β and p-P65 protein in myocardial tissue was upregulated(P < 0.05). Proteins expression of Nlrp3,Pro-caspase1,IL-1β in macrophages stimulated by IS were upregulated,compared with those in the control group(P < 0.05).Conclusion Left ventricular hypertrophy in uremic cardiomyopathy rats is closely related to the up-regulation of serum IS level,which may be highly related to the activation of Nlrp3 inflammasomes through NF-kB signaling pathway.