瞬时受体电位通道亚族M7样电流在小鼠心肌梗死后的变化及意义

Changes and significance of transient receptor potential melastatin 7 after myocardial infarction in the mouse

目的观察小鼠心肌成纤维细胞（CFs）在心肌梗死后瞬时受体电位通道亚族M7（TRPM7）样电流的变化及其对胶原生成的影响，探讨TRPM7离子通道在心脏纤维化形成中的潜在病理生理作用。方法（1）制备小鼠心肌梗死模型并分离CFs细胞；（2）培养传代CFs及小分子干扰RNA（siRNA）技术感染；（3）应用膜片钳技术观察CFs缺血后TRPM7通道内外向电流特征；（4）钙荧光显像技术观察缺血心肌对CFs的钙离子内流影响；（5）测定缺血对CFs总胶原含量的影响。结果（1）心肌缺血能使CFs的含钙离子内向电流较对照组显著增加，分别为（7．4±0．7）pA／pF和（16．2±1．7）pA／pF（P〈0．05）；（2）SiRNA使TRPM7样电流的mRNA水平明显下降，且电流幅值减少约90％；（3）心肌缺血组CFs的TRPM的mRNA丰度及总胶原含量较基础值增加2．3倍左右。结论致纤维化因子心肌缺血可通过TRPM7样电流介导的钙离子信号机制调节CFs功能，在心肌组织纤维化的病理生理过程中发挥重要作用。

Objective To investigate the changes of TRPM 7-like current in mouse cardiac fibroblast （CFs） after myocardial infarction and the effect of myocardial ischemia on the TRPM 7 expression and current. Methods （1） The model of myocardial infarction was made and CFs were isolated ; （2） CFs were cultured and infected by TRPM 7 siRNA ; （3） The effects of myocardial ischemia on TRPM 7 current were recorded by whole cell patch clamp technique; （4） The influences of myocardial ischemia on Ca^2＋ influx in CFs were recorded by Ca^2＋ fluorescence imaging. （5） The effects of ischemia on total collagen content of CFs were studied. Results （1） Ca^2＋ inward current of CFs was increased after myocardial infarction （（16.2±1, 7） vs. （7.4±0.7） pA/pF, P〈0. 053 ; （2） TRPM 7 current was reduced by 90% after siRNA infeetion; （3） The total collagen content of CFs after ischemia was approximately 2.3-fold higher than basic value. Conclusions Ca^2＋ influx in CFs plays an important role in the pathophysiological process of myocardial fibrosis.