Role of NLRP3 inflammasome in therapeutic mild hypothermia post-treated myocardial ischemia-reperfusion rats
Objective To analyze the role of NOD-like receptor thermal protein domain associated protein 3(NLRP3)inflammasome in a therapeutic mild hypothermia(34℃)treated isolated rat myocardial ischemia-reperfusion model and explore its mechanism.Methods Sixty clean grade adult male SD rats,aged 7-10 weeks,weighing 250-300 g.Using a random number table method,the rats were divid-ed into five groups:blank control group(group S),myocardial ischemia-reperfusion group(group IR),34℃mild hypothermia post-treated myocardial ischemia-reperfusion group(group MH),34℃mild hypother-mia post-treated myocardial ischemia-reperfusion+3-TYP group(group HT),and 34℃mild hypothermia post-treated myocardial ischemia-reperfusion+3-TYP+MCC950 group(group HTM),12 rats in each group.Group S perfused the rat heart at 37℃with a balanced perfusion solution for 180 minutes.Group IR re-ceived balanced perfusion of the rat heart at 37℃for 30 minutes,followed by ischemia for 30 minutes and reperfusion with 37℃perfusion for 120 minutes.Group MH perfused the rat heart at 37℃for 30 minutes,followed by ischemia for 30 minutes and reperfusion with 34℃perfusion solution for 120 minutes.Group HT perfused the hearts of rats at 37℃for 30 minutes,followed by ischemia for 30 minutes,silent mating type information regulation 2 homolog 3(sirt3)inhibitor 3-TYP was added to the perfusate,and then per-fused at 34℃for 120 minutes.Group HTM perfused the hearts of rats at 37℃for 30 minutes,followed by ischemia for 30 minutes,sirt3 inhibitor 3-TYP and NLRP3 inhibitor MCC950 were added to the perfusate,and then perfused at 34℃for 120 minutes.The isolated heart was obtained 120 minutes after reperfusion,and the concentrations of IL-6 and IL-1β in the perfused cardiac fluid was measured using ELISA method,Western blot method for detecting the relative content of NLRP3 and sirt3 proteins in myocardial tissue,1%triphenyl tetrazolium chloride staining for calculating myocardial infarction area,and HE staining for observ-ing myocardial pathological changes.Results Compared with group S,HR were significantly slowed down,LVSP,±dp/dtmax were significantly decreased,and LVEDP were significantly increased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage,and the per-centage of myocardial infarction area were significantly increased in groups IR,MH,HT,and HTM(P＜0.05),the content of sirt3 protein in myocardial tissue were significantly reduced,while the content of NLRP3 protein were significantly increased in groups IR,HT,and HTM(P＜0.05),the contents of sirt3 and NLRP3 protein in the myocardial tissue were significantly increased in group MH(P＜0.05).Com-pared with group IR,HR were significantly increased,LVSP,±dp/dtmax were significantly increased,and LVEDP were significantly decreased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage and the percentage of myocardial infarction area were significantly decreased in groups MH and HTM(P＜0.05),the content of sirt3 protein in myocardial tissue was signifi-cantly increased,while the content of NLRP3 protein was significantly decreased in group MH(P＜0.05),the content of NLRP3 protein in myocardial tissue was significantly reduced in group HTM(P＜0.05).Compared with group MH,HR were significantly slowed down,LVSP,±dp/dtmax were significantly de-creased,and LVEDP were significantly increased 30,60,90,and 120 minutes after reperfusion,the con-centrations of IL-6 and IL-1β in cardiac fluid leakage,the percentage of myocardial infarction area,and the content of NLRP3 protein in myocardial tissue were significantly increased in group HT(P＜0.05),the content of sirt3 protein in myocardial tissue was significantly reduced in groups HT and HTM(P＜0.05).Compared with group HT,HR were significantly increased,LVSP,±dp/dtmax were significantly increased,and LVEDP were significantly decreased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage,the percentage of myocardial infarction area,and the content of NLRP3 protein in myocardial tissue were significantly reduced in group HTM(P＜0.05).Conclusion Therapeutic mild hypothermia(34℃)can improve hemodynamic parameters of isolated hearts and reduce the concentrations of IL-6 and IL-1β,NLRP3 protein content in myocardial tissue,percentage of myocardial infarction area,improve myocardial pathological changes,and reduce myocardial ischemia-reperfusion injury in rats,the mechanism may be related to the mitochondrial mediated sirt3 pathway inhibiting the high expres-sion of inflammatory corpuscle NLRP3.
MyocardiumIschemia-reperfusionMild therapeutic hypothermiaNOD-like receptor thermal protein domain associated protein 3Silent mating type information regulation 2 homolog 3Inflam-matory corpuscleMitochondrion
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