Objective：To assess the effects of Qishen Granule（芪参颗粒, QSG） on sarcoplasmic reticulum（SR） Ca^2＋ handling in heart failure（HF） model of rats and to explore the underlying molecular mechanisms. Methods：HF ...Objective：To assess the effects of Qishen Granule（芪参颗粒, QSG） on sarcoplasmic reticulum（SR） Ca^2＋ handling in heart failure（HF） model of rats and to explore the underlying molecular mechanisms. Methods：HF rat models were induced by left anterior descending coronary artery ligation surgery and high-fat diet feeding. Rats were randomly divided into sham（n=10）, model（n=10）, QSG（n=12, 2.2 g/kg daily） and metoprolol groups（n=12, 10.5 mg/kg daily）. The therapeutic effects of QSG were evaluated by echocardiography and blood lipid testing. Intracellular Ca^2＋ concentration and sarco-endoplasmic reticulum ATPase 2a（SERCA2a） activity were detected by specific assay kits. Expressions of the critical regulators in SR Ca^2＋ handling were evaluated by Western blot and real-time quantitative polymerase chain reaction. Results：HF model of rats developed ventricular remodeling accompanied with calcium overload and defective Ca^2＋ releaseuptake cycling in cardiomyocytes. Treatment with QSG improved contractive function, attenuated ventricular remodeling and reduced the basal intracellular Ca^2＋ level. QSG prevented defective Ca^2＋ leak by attenuating hyperphosphorylation of ryanodine receptor 2, inhibiting expression of protein kinase A and up-regulating transcriptional expression of protein phosphatase 1. QSG also restored Ca^2＋ uptake by up-regulating expression and activity of SERCA2 a and promoting phosphorylation of phospholamban. Conclusion：QSG restored SR Ca^2＋cycling in HF rats and served as an ideal alternative drug for treating HF.展开更多
T-wave alternans, a specific form of cardiac alternans, has been associated with the increased suscep- tibility to cardiac arrhythmias and sudden cardiac death （SCD）. Plenty of evidence has related cardiac alternans...T-wave alternans, a specific form of cardiac alternans, has been associated with the increased suscep- tibility to cardiac arrhythmias and sudden cardiac death （SCD）. Plenty of evidence has related cardiac alternans at the tissue level to the instability of voltage kinetics or Ca^2＋ handling dynamics at the cellular level. However, to date, none of the existing experiments could identify the exact cellular mechanism of cardiac alternans due to the bi-directional coupling between voltage kinetics and Ca^2＋ handling dynamics. Either of these systems could be the origin of alternans and the other follows as a secondary change, therefore making the cellular mechanism of alternans a difficult chicken or egg problem. In this context, theoretical analysis combined with experimental techniques provides a possibility to explore this problem. In this review, we will summarize the experimental and theoretical advances in understanding the cellular mechanism of alternans. We focus on the roles of action potential duration （APD） restitution and Ca^2＋ handling dynamics in the genesis of alternans and show how the theoretical analysis combined with experimental techniques has provided us a new insight into the cellular mechanism of alternans. We also discuss the possible reasons of increased propensity for alternans in heart failure （HF） and the new possible therapeutic targets. Finally, according to the level of electrophysiological recording techniques and theoretical strategies, we list some critical experimental or theoretical challenges which may help to determine the origin of alternans and to find more effective therapeutic tar- gets in the future.展开更多
基金Supported by the National Natural Science Foundation of China(No.81530100,81470191,and 81302908)
文摘Objective：To assess the effects of Qishen Granule（芪参颗粒, QSG） on sarcoplasmic reticulum（SR） Ca^2＋ handling in heart failure（HF） model of rats and to explore the underlying molecular mechanisms. Methods：HF rat models were induced by left anterior descending coronary artery ligation surgery and high-fat diet feeding. Rats were randomly divided into sham（n=10）, model（n=10）, QSG（n=12, 2.2 g/kg daily） and metoprolol groups（n=12, 10.5 mg/kg daily）. The therapeutic effects of QSG were evaluated by echocardiography and blood lipid testing. Intracellular Ca^2＋ concentration and sarco-endoplasmic reticulum ATPase 2a（SERCA2a） activity were detected by specific assay kits. Expressions of the critical regulators in SR Ca^2＋ handling were evaluated by Western blot and real-time quantitative polymerase chain reaction. Results：HF model of rats developed ventricular remodeling accompanied with calcium overload and defective Ca^2＋ releaseuptake cycling in cardiomyocytes. Treatment with QSG improved contractive function, attenuated ventricular remodeling and reduced the basal intracellular Ca^2＋ level. QSG prevented defective Ca^2＋ leak by attenuating hyperphosphorylation of ryanodine receptor 2, inhibiting expression of protein kinase A and up-regulating transcriptional expression of protein phosphatase 1. QSG also restored Ca^2＋ uptake by up-regulating expression and activity of SERCA2 a and promoting phosphorylation of phospholamban. Conclusion：QSG restored SR Ca^2＋cycling in HF rats and served as an ideal alternative drug for treating HF.
基金Project supported by the National Basic Research Program （973） of China （No. 2007CB512100） and the National Natural Science Foun- dation of China （Nos. 81171421 and 61101046）
文摘T-wave alternans, a specific form of cardiac alternans, has been associated with the increased suscep- tibility to cardiac arrhythmias and sudden cardiac death （SCD）. Plenty of evidence has related cardiac alternans at the tissue level to the instability of voltage kinetics or Ca^2＋ handling dynamics at the cellular level. However, to date, none of the existing experiments could identify the exact cellular mechanism of cardiac alternans due to the bi-directional coupling between voltage kinetics and Ca^2＋ handling dynamics. Either of these systems could be the origin of alternans and the other follows as a secondary change, therefore making the cellular mechanism of alternans a difficult chicken or egg problem. In this context, theoretical analysis combined with experimental techniques provides a possibility to explore this problem. In this review, we will summarize the experimental and theoretical advances in understanding the cellular mechanism of alternans. We focus on the roles of action potential duration （APD） restitution and Ca^2＋ handling dynamics in the genesis of alternans and show how the theoretical analysis combined with experimental techniques has provided us a new insight into the cellular mechanism of alternans. We also discuss the possible reasons of increased propensity for alternans in heart failure （HF） and the new possible therapeutic targets. Finally, according to the level of electrophysiological recording techniques and theoretical strategies, we list some critical experimental or theoretical challenges which may help to determine the origin of alternans and to find more effective therapeutic tar- gets in the future.
