钙三醇和甲状旁腺素对鼠心肌细胞凋亡的影响及机制

Effects of calcitriol and parathyroid hormone on the apoptosis of rat cardiac myocyte and its mechanism

目的研究甲状旁腺素(parathyroidhormone,PTH)对心肌细胞内游离钙和细胞凋亡的影响,以及钙三醇的修复作用。方法利用培养的新生SD大鼠(n=25)心肌细胞,以Fluo-3/AM负载,通过激光共聚焦显微镜测定细胞内游离钙浓度([Ca2+]i);采用透射电镜和流式细胞仪观察细胞凋亡的变化。结果PTH1-340.01μmol/L和0.1μmol/L刺激7d后,心肌细胞内钙荧光强度分别为186.0±43.6,217.9±22.2,、细胞凋亡率分别为(6.97±1.00)%和(12.58±1.75)%较对照组[(77.7±19.9)%,(0.12±0.11)%]显著增加,差异有显著性意义(F=158.52,54.19,P<0.01)。若以PTH1-340.1μmol/L刺激,并同时加入0.001μmol/L的钙三醇干预上述指标明显降低[分别为(114.3±29.9)%,(3.43±0.40)%],差异有显著性意义(F=158.52,54.19,P<0.01);但同时应用0.1μmol/L钙三醇干预,则无显著改善。结论PTH1-34可以浓度依赖性增加心肌细胞内[Ca2+]i,诱导细胞肥大和凋亡;适宜浓度的钙三醇干预,具有修复作用。

AIM:To study the influence of parathyroid hormone(PTH) on intracellular calcium concentration(i)and apoptosis,and the repairing effect of calcitriol in rat cardiac myocytes.METHODS:i in cultured cardiac myocytes of newborn rats was measured by confocal microscopy using Fluo 3/AM as fluorescent indicator.The changes of apoptosis were observed by using flow cytometer and electron microscope.RESULTS:After 7 day exposure to PTH1 34 of 0.01 μmol/L and 0.1 μmol/L,fluorescent intensity(FI)of i and apoptosis rate(APO) of cardiac myocytes were 186.0±43.6 and 217.9±22.2,(6.97±1.00)%and(12.58±1.75)%,respectively,which were significantly higher than those in the control group[(77.7±19.9)%,(0.12±0.11)%](F=158.52, 54.19,P< 0.01).When the cells were co treated with 0.001 μmol/L calcitriol and 0.1 μmol/L PTH 1 34,the indexes mentioned above were decreased significantly,which were (114.3±29.9)%and(3.43±0.40)%respectively(F=158.52,54.19,P< 0.01).However,when the concentration of calcitriol was 0.1 μmol/L,there were no obvious changes.CONCLUSION:PTH1 34 dose dependently inducedi and APO of cardiac myocytes,and proper concentration of calcitriol has the repairing effect.