Reaserch On Action Of IMD On The ATP-Sensitive Potassium Channel In Myocardial Ischemia-Reperfusion

Objective:To observe the protection mechanism under the circumstance when Intermedin IMD involves in myocardial ischemia-reperfusion injury in isolated rat hearts after treatment in the period of myocardial ischemia; to study whether the protective action of IMD on cardiac muscle cell is via ATP-sensitive potassium channel KATP or not, so as to provide the clinical ideas for the discussion on the mechanism of myocardial protection.Method:45standard SD rats are selected and divided into three groups:ischemia reperfusion group (I/R group), IMD treatment group (IMD group), and glibenclamide+IMD treatment group (Gli+IMD group), there are15rats in each group. For each group,3mL arterial blood is drawn respectively during the late period of reperfusion, blood serum CK and LDH are determined by colorimetric method, and the activity of cTnI is measured by means of ELISA. Take the cardiac muscular tissue at the apex of heart, which is then fixed by formalin and imbedded by paraffin, so as to observe the extent of myocardial damage by light microscopy.Results:Each group of animal body weight, HR and MAP after threading stable showed no significant difference (P>0.05). Compared with the sham group, the I/R group, the IMD group, Gli+IMD group cTnl and LDH, CK were elevated, but there was no statistically significant (P>0.05) in the IMD group, compared to the IMD group and Gli+IMD group, there was statistically significant (P<0.05); there was statistically significant between the IMD group and the I/R group, Gli+the IMD group (P<0.05); there was no statistically significant between I/R group and Gli+IMD group (P>0.05). The AAR/LV (%):In the I/R group, Gli+IMD group and IMD group,there were no significant difference (P>0.05); AN/the AAR (%):There were statistically significant between IMD group and I/R group, Gli+the IMD group (P<0.05).There was no statistically significant between Gli+IMD and I/R group(P<0.05). Light microscope, the sham group was normal, and I/R group is mainly eosinophilic cytoplasm degeneration, the wide range of area was red dye, myocardial stripes is unclear or even disappear, wavy or broken fusion of myocardial fibers, the sarcoplasmicirregular coarse particles, a significant cell necrosis, interstitial hyperemia and edema, hemorrhage,and neutrophil cell infiltration; In the IMD group,myocardial tissue cell nuclei size size is consistent, cytoplasmic eosinophilic change, myocardial fibers slightly elongated, tapered, and occasional fibroblasts and inflammatory cell infiltration;In the Gli+IMD group,myocardial fibers lengthen,the muscle fibers were wavy, disorganized and irregular,myocardial interstitial had inflammatory cell infiltration.Conclusion:IMD involved in activation of ATP-sensitive potassium channels in myocardial ischemia reperfusion injury associated with myocardial cell protective effects, in-depth study of great significance for the prevention and treatment of cardiovascular disease.