The effect of mitochondrial oxidative stress and the expression of Bcl-2 and Bax proteins on cardiomyocyte apoptosis during hypoxia postconditioning
10.3760/cma.j.issn.0253-3758.2012.06.013
- VernacularTitle:缺氧后处理中线粒体氧化应激平衡对缺氧复氧大鼠心肌细胞凋亡的影响
- Author:
Rong-Hui TU
1
;
Li CHEN
;
Guo-Qiang ZHONG
;
Zhi-Yu ZENG
;
Qing-Jie LI
;
Yan HE
;
Yan HE
;
Jin-Yi LI
Author Information
1. 广西医科大学第一附属医院
- Keywords:
Apoptosis;
Reactive oxygen species;
Postconditioning
- From:
Chinese Journal of Cardiology
2012;40(6):516-521
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate mitochondrial oxidative stress on cardiomyocyte apoptosis and the expression of Bcl-2 and Bax proteins in cardiac sarcolemma and mitochondria after application of hypoxia postconditioning and free radical scavengers.Methods Primary cultured neonatal rat cardiomyocytes were exposed to 3 h hypoxia ( H ) followed by ( 1 ) 6 h of reoxygenation (R) (H/R),(2) 3 intermittent cycles of 5 min H and R before 6 h of R (PC),(3) application of superoxide dismutase (SOD) before PC ( SOD +PC),(4) application of catalase (CAT) before PC ( CAT + PC ),and (5) application of SOD plus CAT before PC (SOD + CAT + PC ).Cardiac sarcnlemma and mitochondria were isolated by differential centrifugation.Mitochondrial reactive oxygen species (ROS) was detected with fluorescent probes ( DCFHDA) and cardiomyocyte apoptosis was detected with flow cytometry.The expressions of Bcl-2 and Bax proteins in cardiac sarcolemma and mitochoncria were measured by Western blot.Results Mitochondrial ROS reduced significantly in PC,SOD + PC,CAT + PC and especially in SOD + CAT + PC groups ( all P ＜0.01 ).The number of apoptotic cardiomyocytes reduced significantly in PC,SOD + PC and CAT + PC ( all P ＜0.01 ) but not in SOD + CAT + PC groups.Bcl-2 levels increased while Bax levels decreased in cardiac sarcolemma and mitochondria in PC,SOD + PC and CAT + PC groups (all P＜0.01 ),Bcl-2 levels decreased and Bax levels increased in H/R and PC + SOD + CAT groups ( all P ＜0.01 ).Conclusions PC attenuated H/R induced ROS and cardiomyocyte apoptosis,which might be mediated by upregulating the expression of Bcl-2 and downregulating the Bax in mitochondria and sarcolemma:SOD or CAT alone did not but SOD plus CAT attenuate the anti-apoptotic effect of hypoxia postconditioning:mitochondrial ROS thus plays an important role in PC's cardioprotection.
