钙敏感受体在缺氧-复氧诱导的大鼠心肌细胞凋亡中的作用

目的： 观察大鼠心肌钙敏感受体(CaSR) 在心肌缺氧/再灌注损伤时的表达情况及其介导的细胞内钙变化，以及其参与细胞凋亡的相关信号转导途径。方法： Lagendorff离体灌流方法复制心脏缺氧-复氧（anoxia-reoxygenation，A/R）模型；观察缺氧/再灌注及加入CaSR激动剂时CaSR的表达；应用激光扫描共聚焦显微镜（LSCM）观察大鼠心肌细胞正常、缺氧、缺氧/再灌注时［Ca2+］i变化；HE染色观察细胞形态学改变；TUNEL染色观察细胞凋亡； Western blotting检测心肌组织胞浆中caspase 3、caspase 9 的表达。结果： 心肌A/R组及加入CaSR激动剂时CaSR的表达明显增高，细胞内钙明显升高。HE染色发现A/R组和激动剂组损伤明显，TUNEL显示2组凋亡细胞大量存在。同时，A/R组和激动剂组胞浆中caspase 3和caspase 9的表达增加。结论： CaSR参与大鼠心肌A/R损伤时细胞内钙超载的形成，并促进A/R损伤时心肌细胞凋亡。

Role of calcium-sensing receptor in apoptosis of rat cardiomyocytes induced by anoxia-reoxygenation

AIM:To observe the expression of calcium-sensing receptor(CaSR) of rat cardiomyocytes in anoxia-reoxygenation(A/R) injury and CaSR-induced changes of intracellular calcium;involvement of CaSR in apoptosis and relevant signaling transduction pathway.METHODS:The A/R injury was remodeled in vitro;CaSR,caspase 3 and caspase 9 were deteced by Western blotting.LSCM was used to observe changes of intracellular calcium during reperfusion with or without CaSR agonist.Morphological changes in different groups were observed by light microscopes.Apoptotic cells were measured by TUNEL assay.RESULTS:By LSCM,it was found that the intracellular calcium was significantly increased during reperfusion both in A/R and activator group.Severe injury was found by HE staining in the above two groups,the number of apoptotic cells was significantly increased according to TUNEL assay.The expression of CaSR,caspase 3 and caspase 9 was significantly increased in A/R group and activator group compared with control.CONCLUSION:CaSR is involved in intracellular calcium overload in A/R cardiomyocyte,which can accelerate apoptosis during A/R.