Effect and Mechanism of SIRT3 Deficiency on Myocardiac Injury in Sepsis
Objective To investigate the effect of SIRT3 deficiency on myocardiac injury induced by lipopolysaccharide(LPS)in sepsis and its mechanism.Methods SIRT3gene knockout(SIRT3-/-)mice and wild-type(WT)mice were intraperitoneally injected with LPS(10mg/kg)for 24h to prepare myocardial injury model of sepsis,and equal volume normal saline(NS)was injected intraperito-neally as control,WT-NS group,WT-LPS group,SIRT3-/--LPS group and SIRT3-/--NS group were set up.Human heart micro-vascular endothelial cells were stimulated with LPS(10μg/ml)for 24h to prepare cell damage models.Normal culture was used as con-trol,SIRT3 overexpressing lentivirus and negative control virus were used for cell transfection.Control group,LPS group,LPS+SIRT3 overexpressing group and negative control virus group were set up.The left ventricular posterior wall thickness at the end of systole and di-astole and the left ventricular end-diastolic volume were measured by cardiac ultrasound.Sirius red staining was used to detect collagen content in heart tissue of each group.The expression of endothelial-to-mesenchymal transition(EndMT)markers in cardiac microves-sels,which involved platelet-endothelial cell adhesion molecule(CD31)and α-smooth muscle actin(α-SMA)was observed by im-munofluorescence method.Western blot was used to detect the expression of CD31,α-SMA and SIRT3 proteins and autophagy related proteins LC3 and p62.Results Cardiac ultrasound showed that the left ventricular end-diastolic volume,end-systolic and end-dias-tolic posterior wall thickness increased in the SIRT3-/--LPS group(P＜0.001).The results of sirius red staining showed that SIRT3 defi-ciency significantly increased the collagen content of LPS-induced heart tissue of mice(P＜0.001).LPS could induce EndMT in cardiac microvascular endothelial cells of mice,which was aggravated by SIRT3deficiency(P＜0.05).The level of autophagy in heart tissue of mice was stress increased,which was induced by LPS treatment.However,SIRT3deficiency could reduce autophagy level(P＜0.05).In vitro experiments also confirmed that LPS induced increased autophagy stress in human heart microvascular endothelial cells(P＜0.001),and decreased SIRT3 protein expression was accompanied by the occurrence of EndMT(P＜0.05).The overexpression of SIRT3 significantly re-duced the degree of EndMT(P＜0.001),and the autophagy level was further increased(P＜0.05).Conclusion SIRT3 deficiency can aggravate the degree of cardiac diastolic dysfunction and fibrosis in LPS-induced sepsis mice,and the mechanism may be related to inhibi-ting the autophagy level of heart tissue and promoting the development of EndMT in cardiac microvascular endothelial cells.
NETL
NSTL
万方数据
