钙三醇干预甲状旁腺素诱导的心肌细胞内钙超载和细胞肥大  

Protective roles of calcitriol on overload of intracellular calcium and hypertrophy of cardiomyocytes induced by parathyroid hormone

作　　者：赵卫红[1] 张晓文[1] 王笑云[1] 

机构地区：[1]南京医科大学第一附属医院,南京210029

出　　处：《中国血液净化》2009年第5期256-259,共4页Chinese Journal of Blood Purification

基　　金：江苏省高等学校"青蓝工程"项目基金(200109)

摘　　要：目的探讨甲状旁腺素(PTH)对鼠心肌细胞内游离钙([Ca2+]i)和心肌肥大的影响及其机制,以及钙三醇的干预作用。方法培养的新生大鼠心肌细胞以Fluo-3/AM负载,通过激光共聚焦显微术(LSCM)测定细胞内[Ca2+]i;以细胞面积和细胞蛋白含量作为心肌细胞肥大指标,体外实验观察PTH瞬时和持续刺激对鼠心肌细胞[Ca2+]i和肥大的影响,以及钙三醇的干预作用。结果①在细胞外Ca2+为2.5mmol/L时,PTH1-34在0.1和1μmol浓度下的刺激可促使心肌细胞静息[Ca2+]i荧光强度(FI)快速上升;1μmol浓度PTH1-34刺激,在细胞外液无钙,或应用10μmol硝苯地平预处理时,心肌细胞静息钙则无明显上升。②培养的心肌细胞应用PTH1-340.01和0.1μmol刺激7天后,心肌细胞内钙荧光强度、心肌细胞面积和蛋白含量均较对照组显著增加。若以PTH1-340.1μmol刺激,并同时加入0.001μmol的钙三醇干预,上述指标明显降低(P<0.01);但应用0.1μmol高浓度钙三醇干预,上述指标则未见显著改善。结论PTH1-34刺激可显著增加培养心肌细胞[Ca2+]i,诱导细胞肥大;适宜浓度钙三醇具有保护作用,电压依赖型钙通道的开放引起的细胞外钙内流增加是PTH1-34诱导上述变化的重要机制之一。Objective To observe the effects of calcitriol on intracellular calcium concentration （[Ca^2＋]i） and hypertrophy of cardiomyocytes induced by parathyroid hormone （PTH）. Materials and Methods Cultured neonatal rat cardiomyocytes were loaded with Fluo-3/AM, and [Ca^2＋]i was determined by a laser confocal microscope. Hypertrophic response of neonatal rat cardiomyocytes was assayed by measuring cell surface area and protein content. Results （a） When the extracellular Ca^2＋ was 2.5mmol/L, rapid stimulation of PTH1-34 at the concentration of 0.1 and 1 umol/L significantly elevated fluorescence intensity of [Ca2 ＋]i in cardiomyocytes （P 〈 0.01）. However, when the extracellular fluid contained no calcium or the cardiomyocytes were pre-treated with 10umol/L nifedipine, 1 umol/L PTH1-34 did not induce the increase of fluorescence intensity any more. （b） When the cardiomyocytes were treated in 0.01 and 0.1 umol/L PTH1-34 for 7 days, their surface area, protein content and [Ca^2＋]i increased significantly, especially those treated in 0.1 umol/L PTH1-34. If the cells were co-treated with 0.001 lumol/L calcitriol and 0.1umol.L-1 PTH1 34, their surface area, protein content and [Ca^2＋]i attenuated significantly. However, when the calcitriol concentration increased to 0.1 umol/L in the co-treatment experiment, these changes remained. Conclusion Cardiomyocyte hypertrophy was induced by PTH1-34, and was inhibited by appropriate concentration of calcitriol. Calcium influx through voltage-dependent channel induced by PTH may be one of the important mecha- nisms leading to cardiomyocyte hypertrophy.

关 键 词：钙三醇 甲状旁腺素(PTH) 心肌细胞 细胞内游离钙([Ca2+]i) 心肌肥大 

分 类 号：R692.5[医药卫生—泌尿科学]