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）

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.

Involvement of peripheral benzodiazepine receptor in the regulation of rat cardiac mitochondria permeability transition / 中国药理学通报

Aim To investigate the role of peripheral benzodiazepine receptor in rat cardiac mitochondrial permeability transition.Methods The isolated rat cardiac mitochondria were incubated with different doses(50,100,200 ?mol?L-1) of PBR antagonist 1-(2-chlorophenyl-N-methyl-1-methylpropyl)-3-isoquinolinecarboxamide (PK 11195). In additional group(CsA group), 5 ?mol?L-1 cyclosporine A (CsA), an inhibitor of MPT was added 5 minutes before the addition of 100 ?mol?L-1 PK 11195. Negative control group(Con group) was given none treatment. Positive control group(Ca2+ group) was given 150 ?mol?L-1 CaCl2. The absorbanceat 520 nm(Abs 520 nm) was monitored with a split-beam spectrophotometer at 30℃ for 10 min. The mitochondrial ultrastructure was assessed by transmission electron microscopy. Mitochondrial cytochrome C release was demonstrated by Western Blotting.Results PK11195 triggered large-amplitude mitochondrial swelling in a dose dependent manner(vs Con group,P