| Part Ⅰ: The protective effect of Y-27632 on myocardial ischemia-reperfusion injury in rats in vivo and its mechanismObjective: This study was designed to evaluate the cardioprotective effects of the Rho kinase inhibitor Y-27632 on a rat in vivo model of ischemia-reperfusion injury and its underlying mechanisms.Methods: 60 adult male SD rats were randomly divided into 4 groups(n = 15):normal control group(sham group),ischemia-reperfusion group(I/R group),Dil group(diltiazem group),Y-27632 group.Diltiazem(10 mg/kg)was given daily to diltiazem group,Y-27632(5 mg / kg)to Y-27632 group,and the other two groups were given equal volume of water.Five days later,using 30 minutes ischemia and 120 minutes reperfusion,then cardiac tissue and blood samples were collected immediately.Myocardial infarction was detected by TTC staining.Cardiac pathological changes were analyzed by HE staining.Serum pro-inflammatory factors(IL-6,TNF-α,IL-1 β)and myocardial enzymes(CK,LDH)were detected by ELISA.Myocardial apoptosis was detected by TUNEL method.Myocardial apoptosis index(AI)were calculated.The expression of Rho A/ROCK,MAPK(p-JNK/ERK/P38)and p-NF-κB/P-IκB and apoptosis related proteins(Bcl-2,Bax,caspase-3 and caspase-9)in myocardium were detected by the method of western blotting.Results: According to TTC staining and histopathological diagnosis,compared with I/R group,Y-27632 showed a significant reduction in myocardial infarction area and myocardial injury,no significant difference between Dil group(positive control group)and Y-27632 group;compared with I/R group,Y-27632 significantly down-regulated the levels of inflammatory factors and myocardial enzymes in serum,no significant difference between Dil group and Y-27632 group;Compared with the I / R group,AI decreased significantly in Y-27632 group,but there were no significant difference between Dil group and Y-27632 group;compared with the I/R group,Y-27632 significantly inhibited mitogen activated protein kinase(MAPK)and nuclear factor NF-κB signal transduction pathway,but there were no significant difference between Dil group and Y-27632 group;In addition,Y-27632 significantly inhibited the expression of pro-apoptosis related proteins and enhanced the expression of anti-apoptosis related proteins in the myocardium of I/R group,but there were no significant difference between Dil group and Y-27632 group.Conclusion: The results of this study indicate that Y-27632 reduces myocardial damage and reduces cardiomyocyte apoptosis by inhibiting the activation of MAPK and NF-κB signaling pathways.Part Ⅱ: The effect of Y-27632 on myocardial protection and its mechanism of ischemia-reperfusion in isolated rat heartsObjective: The aim of this study was to evaluate the cardioprotective effect of the Rho kinase inhibitor Y-27632 on the isolated rat myocardial ischemia-reperfusion model and its underlying mechanisms.Methods: 60 adult male SD rats were randomly divided into 4 groups(n = 15).Langendorff perfusion system was used to establish the isolated heart I/R model.Sham group: normal control group,continuous perfusion without any treatment for180min;I/R group: after 20 minutes of stable cardiac balance,close the perfusion device to make the whole heart ischemia for 30 minutes,and then reopen the perfusion device for 120 min.;I/R + Dil group: after 20 minutes of stable cardiac balance,close the perfusion device to make the whole heart ischemic for 30 minutes,and then use K-H buffer containing Dil(0.2mg / kg)for reperfusion for 120 minutes;I/R + Y-27632 group: after 20 minutes of stable cardiac balance,close the perfusion device to make the whole heart ischemic for 30 minutes,and then use K-H buffer containing Y-27632(0.5mg/kg)for reperfusion for 120 minutes;After the perfusion,the blood flow of coronary artery,myocardial contractility were recorded and analyzed by physiological recorder.The expression of MAPK and NF-κB signaling pathway related proteins and apoptosis related proteins were detected by Western blot.Results: Compared with I/R group,Dil group and Y-27632 group can effectively improve coronary blood flow and myocardial contractility,there were no significant difference between the two groups.Y-27632 can effectively inhibit the expression of MAPK and NF-κB signaling pathway related proteins in rat hearts in vitro,and there were no significant difference compared with Dil group.Y-27632 can also significantly inhibit the expression of pro-apoptosis related protein and enhanced the expression of anti-apoptosis related proteins in Y-27632 group,and there were no significant difference compared with Dil group.Conclusion: The results of this study indicated that Y-27632 reduced myocardial damage by inhibiting the activation of MAPK and NF-κB signaling pathways and the reduce of cardiomyocyte apotosis. |
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