| Objective1.Regarding cardiac function index,infract size,times of arrhythmia as well as concentration of LDH as the indicator to detect the protection effect of CGRP in ischemia reperfusion injury heart at the organ level and the cellular level.2.To investigate the role of signaling pathway of protein kinase A and protein kinase C in the function of CGRP reducing myocardial ischemia reperfusion injury.3.To detect the relationship between ATP sensitive potassium channel and the myocardial protection effect of CGRP.MethodsOrgan levelHealthy grown SpragueDawley males rats about 300g of weight were divided into six groups?n=6?randomly,control group?C group?,ischemia reperfusion group?IR group?,calcitonin gene-related peptide group?CGRP group?,H-89 group,chelerythrine group,5-HD group.An isolated cardiac Langendroff model was established with oxygenated KH solution at 37?.Two parts of experiment were excuted:1.The hearts in C group and IR group were continually perfused with K-H solution for 30min,while the hearts in H-89 group,chelerythrine group and 5-HD group were infused with 3×10-6M H-89,2×10-6M chelerythrine,500uM 5-HD for 30min respectively and 10-8M CGRP at a rate of 0.5ml/min for 20min.The hearts in CGRP group were only infused with 10-8M CGRP for 20min.And then,except for C group,all other four groups of hearts were subjected to ischemia for 30min and reperfusion for120min,while the hearts in C group were continually perfused for 270min.The cardic function test index of left ventricular systolic pressure?LVSP?,left ventricular end-diastolic pressure?LVEDP?,heart rate,maximum rate of increase and decrease in left ventricular pressure and times of arrhythmia were recorded.2.After the first part of experiment,the hearts were collected and freezed at the temperature of-80?for 24h,and the myocardial infract size was calculated by Image J.Cellular levelThe hearts of suckling mice that bron no more than 1 to 3 days were colleced and the myocardial cells were divided from those hearts and were incubated in 6-well plate.18 wells were divided into 6 above mentioned groups randomly,each and every of well was given drugs or blank control for 30min,ischemia for 3 hours and reperfusion for 2hours.The supernatant was collect and the concentration of LDH in each well was meassured by spectrophotometry.Results:1.At organ level,compared with C group,the value of LVDP,ądp/dtmax of IR group,H-89 group,chelerythrine group and 5-HD group were decreased?P<0.05?,whereas the the value LVEDP and the area of infraction of all five other groups were all increased?P<0.05?,the times of arrhythmia in IR group,CGRP group,H89 group and 5-HD group were increased.2.Compared with CGRP group,the value of LVEDP and the area of infraction of IR group,H-89 group,chelerythrine group and 5-HD group were increased?P<0.05?,however the LVDP andądp/dtmax of them were decreased?P<0.05?.3.At the cellular level,compared with C group,the concentration of LDH in IR group,H89 group and 5-HD group were increased rapidly?P<0.05?.there was also statistical different in LDH between CGRP group and IR group,H89 group as well as5-HD group?P<0.05?.Conclusion:1.Decrease the times of arrhythmia,myocardial apoptosis,the injury of myocardial cells,and improve the cardial function could be seen by given CGRP before ischemia reperfusion injury,which indicat that a protection approch could be actived by CGRP.2.This protection effect could be restrainted by given antagonist of protein kinase A and C,indicating that the protection of CGRP was relative with PKA,PKC signal pathway.3.The mitochodrial ATP sensitive potassium channel could be actived by CGRP in the process that CGRP attenuate IR injury. |
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