허혈성 손상 모델에서 양파 추출물의 심근보호 효과
Cardioprotective Effect of Onion Extract against Ischemic Injury In vitro and In vivo
- 주제(키워드) Onion+ Allium+ apoptosis+ ROS+ Ischemia/reperfusion
- 발행기관 아주대학교
- 지도교수 문창현
- 발행년도 2006
- 학위수여년월 2006. 2
- 학위명 박사
- 학과 및 전공 일반대학원 의학과
- 본문언어 영어
초록/요약
Cardiomyocyte apoptosis is one of the pathological features of ischemic heart desease (IHD) and is associated with thrombosis or other acute alterations of coronary atherosclerotic plaques. The mechanisms of these ischemia/reperfusion injuries have been suggested to involve reactive oxygen species (ROS). Allium family, including garlic and onion, are known to have a potential to reduce the detrimental effect of cardiovascular risk factors, and their beneficial roles are suggested to be associated with antioxidant mechanism. Compared to garlic, very few have been reported about the myocardial beneficial effect of onion. Based on these considerations, the present study was designed to test whether onion extract have cardioprotective effect against ischemic injury in H9c2 cell culture system and rat myocardial infarct model in vivo, and if so, whether the beneficial effect of onion is attributed to its antioxidant property. This study also investigated which component of onion extract is involved in the beneficial effect of onion extract. In H9c2 cells, onion extract markedly elicited cardioprotective effect against hypoxia-induced apoptotic death, demonstrated by its inhibitory effect on hypoxia-induced cytochrome c release, caspase-3 activation, and increase in TUNEL-positive cells. Onion extract also inhibited elevation of ROS generation induced by hypoxia. From inhibitory effects of onion extract and a well-known antioxidant trolox on hypoxia-induced decrease in mitochondrial membrane potential. it is suggested that antiapoptotic effect of onion extract is contributed to its antioxidant property, resulting in the inhibition of downstream mitochondrial death pathway. Cardioprotective effect of onion extract has been further demonstrated in rat myocardial infarct model in vivo, showing that administration of onion extract decreased infarct size and TUNEL-positive cells. Among components of onion extract, a major component quercetin showed a remarkable protective effect against ischemic injury in vitro and in vivo. The profile of the cardioprotective effect is same as in the case of onion extract. In conclusion, the results from this study suggest that onion extract has a significant cardioprotective effect contributed to antioxidant activity of its major component quercetin and that the signaling cascade of its antiapoptotic effect involves inhibition of mitochondrial death pathways, including loss of mitochondrial membrane potential, cytochrome c release and activation of caspase-3.
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ABSTRACT i
TABLE OF CONTENTS iv
LIST OF FIGURES vii
LIST OF TABLE ix
ABBREVIATION x
I. INTRODUCTION 1
A. Myocardial ischemia injury 1
B. Effect of onion (Allium cepa) on cardiovascular disease 2
C. Chemical composition of onion and the key health compounds 4
II. AIMS OF STUDY 9
A. Effect of onion extract on ischemia-induced cell death 9
B. Effect of onion component on ischemia-induced cell death 9
III. METHODS 11
A. Cell culture and hypoxia system 11
B. Onion extract treatment 11
C. Lactate dehydrogenase (LDH) assay 12
D. In situ termanal deoxynucleotidyl transferase UTP nick end labeling(TUNEL) 12
E. Caspase-3 activity assay 13
F. Separation of cytosolic and mitochondrial fractions 14
G. Western blot analysis for cytochrome c release 14
H. Intracellular ROS measurement 15
I. Mitochodrial membrane potential (ΔΨm) measurement 16
J. Rat myocardial infarct model 16
K. Measurement of myocardial infarct size 17
L. Statistical analysis 18
IV. RESULTS 19
A. Effect of onion extract against hypoxia-induced cell death 19
B. Effect of onion extract against hypoxia-induced ROS generation 19
C. Effect of onion extract on hypoxia-induced reduction in mitochodrial membrain potential(ΔΨm) 22
D. Effect of onion extract on cytosolic release of cytochrome c by hypoxia 22
E. Activation of caspase-3 during hypoxia 26
F. Effect of onion extract against hypoxia-induced apoptosis 26
G. Effect of onion extract against BSO-induced cell death 26
H. Effect of onion extract against BSO-induced ROS generation 29
I. Effect of onion extract on BSO-induced reduction in mitochodria membrane potential(ΔΨm) 29
J. Effect of onion extract against BSO-induced apoptosis 32
K.Effect of onion extract on infarct size in rat myocardial infarction model 32
L. Effect of onion extract against ischemia-reperfusion induced apoptosis 36
M. Effect of onion compounds against hypoxia-induced cell death 36
N. Effect of quercetin against hypoxia-induced ROS generation 40
O. Effect of quercetin on hypoxia-induced reduction in mitochodria membrane potential(ΔΨm) 40
P. Effect of quercetin on infarct size in rat myocardial infarction model 43
Q. Effect of quercetin against ischemia/reperfusion-induced apoptosis 43
IV. DISCUSSION 46
V. CONCLUSION 51
REFERENCE 52
국문요약 62
