瞬时受体电位亚族M7在小鼠心肌梗死后的表达变化及其意义

目的 观察小鼠心肌梗死后成纤维细胞(CF)上瞬时受体电位亚族M7样电流(TRPM7L)的变化及其对Ca2+信号的影响,探讨瞬时受体电位亚族(TRP)M7离子通道在CF功能中的作用.方法 制备小鼠心肌梗死模型并分离小鼠CF,培养传代小鼠CF及其基因沉默技术(SiRNA)转染,应用膜片钳技术观察小鼠CF缺血后及低pH值溶液下TRPM7L内外向电流特征,用钙荧光显像技术观察缺血心肌、酸性pH值时小鼠CF的Ca2+内流变化,测定缺血时小鼠CF细胞总胶原含量改变.结果 (1)小鼠CF上富含TRPM7表达,且TRPM7L电生理特性与TRPM7通道一致;(2)心肌缺血使小鼠CF的Ca2+内流较对照组增加[(7.4±0.7)pA/pF比(16.2±1.7)pA/pF,P<0.01],而酸中毒时增加3倍;(3)SiRNA显著减少TRPM7L的mRNA丰度和90%的电流幅值.结论 TRPM7是小鼠CF细胞中TRPM7L的分子基础;TRPM7L是CF中钙内流主要媒介;致纤维化因素(缺血、酸中毒等)通过调节TRPM7L介导的Ca2+信号机制影响小鼠CF细胞的病理生理功能,在心肌纤维化的形成中可能发挥重要作用.

Increased expression of transient receptor potential melastatin 7 in mouse cardiac fibroblasts post myocardial infarction

Objective To observe transient receptor potential melastatin 7-like (TRPMTL) expression changes post myocardial infarction (MI) in mouse cardiac fibroblast (CF).Methods TRPM7 expression and Ca2+ influx in CF from MI and control mice were quantified by mRNA RT-PCR and whole cell patch clamp technique.Results (1) TRPM7 expression was significantly upregulated post MI and Ca2+ influx of CF were significantly increased post MI [ (7.4 ± 0.7 ) pA/pF vs.( 16.2 ± 1.7) pA/pF, P < 0.01 ] and Ca2+ influx of CF increased 3-fold under lower pH condition; (2) These effects could be blocked by knock-out TRPM7 gene with SiRNA.conclusion TRPM7L upregulation post MI and under lower pH condition are responsible for increased Ca2+ influx in CF.