中叶素抑制大鼠心脏缺血/再灌注损伤

目的研究中叶素(Intermedin,IMD)对大鼠心脏缺血/再灌注(ischemia/reperfusion,I/R)损伤的保护作用及其可能机制。方法Langendorff方法灌流离体心脏,并造成I/R模型,以Power Lab多导生理记录仪记录灌流心脏心功能的变化,收集灌流后心肌组织及灌流液进行生化检测。结果IMD再灌注明显改善I/R造成的心功能抑制和组织损伤,可升高△LVP、LV±dp/dtmax,降低LVDP,增加心率及冠脉流量,同时使心肌LDH、总蛋白和肌红蛋白的漏出及心肌组织MDA生成明显减少,而心肌组织cAMP含量明显增加。且IMD的上述效应与同浓度ADM的效果相近。此外,I/R后心肌IMD受体Bmax和Kd值均增加。结论IMD有明显的抑制心脏I/R损伤的作用,该作用可能通过cAMP途径介导,且IMD抗I/R损伤的作用与强内源性心血管保护肽肾上腺髓质素相仿。

Intermedin inhibiting cardiac injury induced by ischemic/reperfusion in rat heart

Aim To determine the protective effects of IMD on ischemia/reperfusion(I/R) injury and its possible mechanism.Method Isolated rat hearts were perfused by Langendorff mode,and after 45 min global ischemia and 30 min reperfusion ventricular function was measured on a Power Lab,and adequate amount of ventricular tissues and perfusate were collected for biochemical measurement.Results Treatment with IMD during the reperfusion period significantly attenuated the effects of I/R on cardiac function inhibition and tissue injury.Compared with I/R group,IMD induced increase in △LVP,LV(dp/dtmax,HR and CF,whereas induced decrease in LVDP.Reperfusion with IMD exerted decrease in LDH,total protein,Mb and MDA content compared with I/R group,but increased myocardial cAMP content.All these values were similar to the effects of ADM.Furthermore,I/R induced significant increase in Bmax and Kd value.Conclusion IMD exerted beneficial effects on cardiac injury induced by I/R which might be mediated by cAMP pathway.And the cardioprotective effects of IMD were equal to ADM,a potent cytoprotective factor.