Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs

碩士 === 國立臺灣大學 === 藥理學研究所 === 96 === Thaliporphine is a phenolic aporphine alkaloid which is isolated from Lauraceae, and has high affinity to 5HT7 receptor. Our previous study found that thaliporphine exerted cardioprotection in ischemia-reperfused rat hearts, anti-hyperglycemic effect, and anti-sep...

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Main Authors: Hui-Chun Ku, 辜惠君
Other Authors: Ming-Jai Su
Format: Others
Language:zh-TW
Published: 2008
Online Access:http://ndltd.ncl.edu.tw/handle/26431474132655847738
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description 碩士 === 國立臺灣大學 === 藥理學研究所 === 96 === Thaliporphine is a phenolic aporphine alkaloid which is isolated from Lauraceae, and has high affinity to 5HT7 receptor. Our previous study found that thaliporphine exerted cardioprotection in ischemia-reperfused rat hearts, anti-hyperglycemic effect, and anti-septic effect with the benefit of increasing survival rate and attenuating multiple organ failure. Sepsis is a complicated inflammatory disease. Under pathophysiological conditions, the elevated plasma level of cytokines and inflammatory mediators, such as TNFα, reactive oxygen species, and NO, may cause imbalance between pro- and anti- apoptotic signalings in multiple organs. The imbalance of coagulation and anticoagulation system may increase the occurrence of disseminated intravascular coagulation, and decrease organ blood perfusion and oxygen supply, which result in multiple organ failure. It remains unclear whether cell death could be enhanced in ischemia-reperfused hearts under the circumstance of endotoxemia. The present study aimed to investigate the underlying signaling of cell survival or death in endotoxemic guinea pig hearts subjected to ischemia reperfusion injury, and to examine whether thaliporphine could have benefit in the cardioprotection against ischemia reperfusion injury. Endotoxemic guinea pigs were induced by intraparenteral injection of lipopolysaccaride (LPS) 1mg/kg with or without thaliporphine coadministration. After LPS injection for 24 hours, guinea pigs were anethetized by pentobarbital (40mg/kg, i.p.) to perform the thoracotomy, and the left anterior decending coronary artery of guinea pig hearts were ligated for 30 mins and followed by reperfusion for 1h before excising the heart for the measurement of infarct size by TTC stain or for the protein extraction. As compared with the sham group, the infarct size was markedly increased in association with a prolongation of QTc interval in endotoxemic heart subjected to ischemia reperfusion injury, which could be significantly attenuated in thaliporphine coadministrated endotoxemic guinea pigs. Thaliporphine mediated cardioprotective effect was not affected by pimozide (1mg/kg, i.p.) 5HT7 receptor inhibition. The alteration of protein expression was separatedly analyzed in the non-risk and the risk area of endotoxemic guinea pig hearts subjected to ischemic reperfusion injury. In the non risk area of endotoxemic heart, the protein level of Bax, cleaved PARP, and phospho-JNK was significantly elevated without altering the caspase 9 activity, which was further enhanced in risk area of myocardium in association with the pronounced increase of caspase 9 activity. Thaliporphine treatment significantly attenuated the increased level of phospho-JNK and the cleaved PARP in both non-risk area and risk area of ischemia reperfusion hearts. The suppression of Bax expression by thaliporphine in risk area was in parallel with the attenuation of caspase 9 activity. The intracellular level of ROS and nitric oxide was measured by loading the isolated ventricular cells of guinea pig with CM-H2DCFDA and DAF-AM, respectively. In endotoxemic guinea-pig hearts, the intracellular concentration of both ROS and NO were markedly increased, which was significantly attenuated in thaliporphine coadministrated group. The increased cGMP level was found in endotoxemic guinea pig hearts and was not significantly altered in thaliporphine coadminstrated endotoxemic guinea pig hearts. In conclusion, the pro-apoptotic signaling was initiated in endotoxemic guinea pig hearts, which had an impact on the tolerance of myocardium against ischemia reperfusion injury. The elevated oxidative stress in endotoxemic guinea pig hearts may increase the formation of oxidative mediators, such as peroxynitrite, to enhance the apoptotic pathway, which results in the aggravation of myocardial infarction after ischemia reperfusion. Thaliporphine treatment attenuated the intracellular ROS and NO in association with the inhibition of JNK phosphorylation which contributed to the anti-apoptotic action and the amelioration of myocardial infarction. Thaliporphine mediated cardioprotective effect was not mediated through the activation of 5HT7 receptor or inhibition cGMP- dependent pathway. The molecular targets of thaliporphine mediated anti-apoptosis in endotoxemic guinea pig hearts remains for further investigation.
author2 Ming-Jai Su
author_facet Ming-Jai Su
Hui-Chun Ku
辜惠君
author Hui-Chun Ku
辜惠君
spellingShingle Hui-Chun Ku
辜惠君
Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs
author_sort Hui-Chun Ku
title Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs
title_short Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs
title_full Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs
title_fullStr Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs
title_full_unstemmed Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs
title_sort mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs
publishDate 2008
url http://ndltd.ncl.edu.tw/handle/26431474132655847738
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AT gūhuìjūn mechanismsofcardioprotectiveeffectofthaliporphineagainstischemiareperfusioninjuryinendotoxemicguineapigs
AT huichunku thaliporphinebǎohùtiānzhúshǔnèidúsùxuèzhèngduìkàngxīnzàngquēxuèzàiguànliúsǔnshāngzhījīzhuǎn
AT gūhuìjūn thaliporphinebǎohùtiānzhúshǔnèidúsùxuèzhèngduìkàngxīnzàngquēxuèzàiguànliúsǔnshāngzhījīzhuǎn
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spelling ndltd-TW-096NTU055500022016-05-11T04:16:25Z http://ndltd.ncl.edu.tw/handle/26431474132655847738 Mechanisms of cardioprotective effect of thaliporphine against ischemia reperfusion injury in endotoxemic guinea pigs Thaliporphine保護天竺鼠內毒素血症對抗心臟缺血再灌流損傷之機轉 Hui-Chun Ku 辜惠君 碩士 國立臺灣大學 藥理學研究所 96 Thaliporphine is a phenolic aporphine alkaloid which is isolated from Lauraceae, and has high affinity to 5HT7 receptor. Our previous study found that thaliporphine exerted cardioprotection in ischemia-reperfused rat hearts, anti-hyperglycemic effect, and anti-septic effect with the benefit of increasing survival rate and attenuating multiple organ failure. Sepsis is a complicated inflammatory disease. Under pathophysiological conditions, the elevated plasma level of cytokines and inflammatory mediators, such as TNFα, reactive oxygen species, and NO, may cause imbalance between pro- and anti- apoptotic signalings in multiple organs. The imbalance of coagulation and anticoagulation system may increase the occurrence of disseminated intravascular coagulation, and decrease organ blood perfusion and oxygen supply, which result in multiple organ failure. It remains unclear whether cell death could be enhanced in ischemia-reperfused hearts under the circumstance of endotoxemia. The present study aimed to investigate the underlying signaling of cell survival or death in endotoxemic guinea pig hearts subjected to ischemia reperfusion injury, and to examine whether thaliporphine could have benefit in the cardioprotection against ischemia reperfusion injury. Endotoxemic guinea pigs were induced by intraparenteral injection of lipopolysaccaride (LPS) 1mg/kg with or without thaliporphine coadministration. After LPS injection for 24 hours, guinea pigs were anethetized by pentobarbital (40mg/kg, i.p.) to perform the thoracotomy, and the left anterior decending coronary artery of guinea pig hearts were ligated for 30 mins and followed by reperfusion for 1h before excising the heart for the measurement of infarct size by TTC stain or for the protein extraction. As compared with the sham group, the infarct size was markedly increased in association with a prolongation of QTc interval in endotoxemic heart subjected to ischemia reperfusion injury, which could be significantly attenuated in thaliporphine coadministrated endotoxemic guinea pigs. Thaliporphine mediated cardioprotective effect was not affected by pimozide (1mg/kg, i.p.) 5HT7 receptor inhibition. The alteration of protein expression was separatedly analyzed in the non-risk and the risk area of endotoxemic guinea pig hearts subjected to ischemic reperfusion injury. In the non risk area of endotoxemic heart, the protein level of Bax, cleaved PARP, and phospho-JNK was significantly elevated without altering the caspase 9 activity, which was further enhanced in risk area of myocardium in association with the pronounced increase of caspase 9 activity. Thaliporphine treatment significantly attenuated the increased level of phospho-JNK and the cleaved PARP in both non-risk area and risk area of ischemia reperfusion hearts. The suppression of Bax expression by thaliporphine in risk area was in parallel with the attenuation of caspase 9 activity. The intracellular level of ROS and nitric oxide was measured by loading the isolated ventricular cells of guinea pig with CM-H2DCFDA and DAF-AM, respectively. In endotoxemic guinea-pig hearts, the intracellular concentration of both ROS and NO were markedly increased, which was significantly attenuated in thaliporphine coadministrated group. The increased cGMP level was found in endotoxemic guinea pig hearts and was not significantly altered in thaliporphine coadminstrated endotoxemic guinea pig hearts. In conclusion, the pro-apoptotic signaling was initiated in endotoxemic guinea pig hearts, which had an impact on the tolerance of myocardium against ischemia reperfusion injury. The elevated oxidative stress in endotoxemic guinea pig hearts may increase the formation of oxidative mediators, such as peroxynitrite, to enhance the apoptotic pathway, which results in the aggravation of myocardial infarction after ischemia reperfusion. Thaliporphine treatment attenuated the intracellular ROS and NO in association with the inhibition of JNK phosphorylation which contributed to the anti-apoptotic action and the amelioration of myocardial infarction. Thaliporphine mediated cardioprotective effect was not mediated through the activation of 5HT7 receptor or inhibition cGMP- dependent pathway. The molecular targets of thaliporphine mediated anti-apoptosis in endotoxemic guinea pig hearts remains for further investigation. Ming-Jai Su 蘇銘嘉 2008 學位論文 ; thesis 56 zh-TW