Effect of mitochondria permeability transition pore on H9c2 myocardial cell apoptosis induced by lipopolysaccharide / 上海交通大学学报（医学版）

ABSTRACT

Objective·To observe mitochondria permeability transition pore (mPTP) opening and apoptosis of H9c2 myocardial cell stimulated by lipopolysaccharide (LPS),and to explore the anti-apoptotic effect of combined application of cyclosporine A (CsA) and ryanodine (Rya).Methods·The H9c2 cells were divided into Control group,LPS group,LPS+CsA group,LPS+Rya group,and LPS+CsA+Rya group.The mPTP opening state,Ca2+ concentration within cell and mitochondrial,mitochondrial membrane potential (AΦm),cell apoptosis,expression of Bax and Bcl-2 at mRNA and protein levels,and activity of caspase 3 were determined respectively.Results·mPTP opened after being stimulated by LPS for 24 h,which increased the fluorescence intensity for Ca2+in cytosolic and mitochondria by 298％ and 231％ respectively,induced about 1/3 cell apoptosis,improved the activity of caspase 3 approximately twice,and enhanced expression ofBax mRNA (P=0.008).The combined use of CsA and Rya effectively inhibited mPTP opening,increased the enhancement of fluorescence intensity for Ca2+in both cytosolic and mitochondria,maintained normal AΦrn,reduced LPS-induced apoptosis,inhibited the activity of caspase 3,and decreased Bax mRNA expression level induced by LPS in the myocardial cells.Conclusion·mPTP plays an important role in in LPS-induced myocardial apoptosis,whereas the combination of CsA and Rya can alleviate it effectively.