溶血磷脂酸对小鼠离体心脏缺血/再灌注损伤及TRPV1表达的影响

Effects of lysophosphatidic acid on ischemia/reperfusion injury and TRPV1 expression in isolated mouse heart

目的探讨溶血磷脂酸(lysophosphatidic acid,LPA)对小鼠离体心脏缺血/再灌注损伤(ischemia/reperfusion injury,IRI)及心脏TRPV1表达的影响。方法Langendorff装置建立离体心脏IRI模型,假手术组(Sham)心脏持续灌注100 min、缺血/再灌注组(IR)心脏稳定跳动10 min,停止灌注30 min后,再灌注60 min、IR+LPA组在IR基础上给予外源性LPA、IR+HA130组在IR前10 min腹腔注射LPA合成抑制剂HA130。TTC染色测定心肌梗死体积,ELISA法测冠脉流出液LPA和LDH水平及血清LPA浓度,Western blot测定心肌组织pTRPV1/TRPV1及Bcl-2/Bax表达。结果与Sham组相比,IR组出现明显心肌梗死,冠脉流出液中LDH水平及LPA水平升高,且LPA水平与心肌梗死体积呈线性相关;心肌组织pTRPV1及TRPV1蛋白表达增加,Bcl-2/Bax比值降低。与IR组相比,IR+LPA组心肌IRI加重。相反,IR+HA130组心肌IRI得到逆转。结论小鼠心脏I/R可诱导LPA释放,加重心肌缺血后损伤,而抑制LPA释放可发挥心肌保护作用,其机制可能与调控心脏TRPV1表达及凋亡信号有关。

Aim To investigate the effects of lysophosphatidic acid on ischemia/reperfusion injury(IRI)and TRPV1 expression in isolated mouse heart.Methods The IRI model of isolated mouse heart was established by Langendorff device.The hearts in sham group were continuously perfused for 100 min.The hearts in IR group were stabilized for 10 min followed by no perfusion for 30 min and reperfusion for 60 min.Exogenous LPA was added in the K-H solution during IR in IR+LPA group while HA130,an LPA synthesis inhibitor,was intraperitoneally injected before IR in IR+HA130 group.The infarct volume was measured by TTC staining,the determination of LPA and LDH levels in coronary effluent and LPA concentration in serum was measured by ELISA method.Finally,the expression levels of pTRPV1/TRPV1 and Bcl-2/Bax in myocardial tissues were determined by Western blot.Results Compared with sham group,IR caused evident myocardial infarction and increased the levels of LDH and LPA in coronary effluent.The increase of LPA was linearly correlated with myocardial infarction volume.In addition,the protein levels of pTRPV1 and TRPV1 in myocardium increased,while the ratio of Bcl-2/Bax decreased.The myocardial injury in IR+LPA group was aggravated.In contrast,myocardial IRI was reversed in IR+HA130 group.Conclusions Myocardial ischemia-reperfusion induces the release of LPA,which aggravates myocardial post-ischemic injury,while the inhibition of LPA release exerts cardioprotective effects.The underlying mechanisms might be related to the regulation on cardiac TRPV1 expression and apoptotic signals.