The Mechanism Of Astragaloide Ⅳ Protect Isolated Rat Hearts Against Anoxia/reoxygenation Injury

Objective: The Astragaloside Ⅳ has been widely used to treat patients with cardiovascular disease,and it has show the protectiveness on hearts’ functions.This sudy adopted isolated heart aortic retrograde perfusion anoxia-reoxygenation injury model in our experiments to research whether AsⅣ pretreated rats through intraperitoneal injection before isolated hearts perfusion manifest protective effect against anoxia-reoxygenation injury,then investigated the role of AsⅣ in anoxia-reoxygenation injury,and expelored the possible mechanism of AsⅣ.Methods: There were 40 healthy rats,excised the rat heart immediately and perfused using the Langendorff technique,to build the anoxia-reoxygenation injury model.There were five groups in this experment,8 rats were randomly distributed into each group :(1)Control group;(2)A/R group;(3)A/R+AsⅣ group;(4)A/R+AsⅣ+ABT 263 group;(5)A/R+ABT 263 group,the ABT 263 is a specific inhibitor of Bcl-2.The signals of the perfusion hearts were collected by the Powerlab system to analyse the hearts functions like LVP and ±dp/dt max.The release of CK and LDH in the perfusion solution during A/R were measured by spectrophotometer.Tetrazolium chloride staining detected the myocardial infarction area and the area at risk after reoxygen.Use TUNEL methode and caspase-3 activity detection methode to measure the level of apoptosis of myocardial cell.Use western blotting to detected the protein expression of Bcl-2 and Cyt-c(cytochrome C)in each group after reoxygen.Results:(1)Compared with Control group,A/R group caused great increases of LVP and infarct size(p<0.01),mean while,the releases of CK and LDH were greatly increased at 20 min after reoxygen(p<0.01),but great decreases of ±dp/dt max(p<0.01),the protein expression of Bcl-2 were also decreased and the release of Cyt-c into cytoplasm significantly increased(p<0.01).(2)In contrast to A/R group,changes of AsⅣ+A/R group on LVP and infarct size were obviously lower(p<0.01),the releases of CK and LDH was evidently decreased at 20 min after reoxygen(p<0.01),the ±dp/dt max were increased(p<0.01),the protein expression of Bcl-2 was increased and the release of Cyt-c into cytoplasm was decreased(p<0.01).(3)Distinct from Pue+A/R group,the LVP and infarct size of AsⅣ+ABT 263+A/R group were partially increased(p<0.05),the releases of CK and LDH at 20 min after reoxygen were also increased(p<0.05),but the ±dp/dt max were decreased(p<0.05),and the protein expression of Bcl-2 was decreased and the release of Cyt-c into cytoplasm was increased(p<0.05).Conclusion:1.The AsⅣ preconditioning is effictive in protecting isolated perfusion rat heart against anoxia-reoxygenation injury.2.The cardioprotection of AsⅣ preconditioning may via Bcl-2 mediated mitochondrial apoptosis pathway.