高糖对心肌细胞t小管结构和JP-2表达的影响

Effects of High Glucose on the Structure of T-tubule and Expression of JP-2 in Cardiomyocytes

目的研究高糖对小鼠心肌细胞横管(t小管)结构和横管结构蛋白亲联蛋白2(junctophilin-2,JP-2)表达的影响,探讨高糖致心脏损害的可能机制。方法获取小鼠心室肌细胞分离培养,并分成两组分别给予高糖和低糖处理。激光共聚焦显微镜成像技术记录两组细胞钙火花(Ca^(2+)spark)变化,测定自发性钙火花频率(Ca^(2+)spark frequency)变化;观察心肌细胞t小管结构变化;免疫印迹法检测JP-2蛋白表达;免疫荧光检测JP-2定位。结果高糖可以明显增加心室肌细胞的自发性钙火花频率,并且高糖对t小管结构的破坏显著,降低t小管上JP-2蛋白的表达。结论高糖通过降低JP-2蛋白的表达进而损害心肌细胞t小管,使其结构发生紊乱,从而增加心室肌细胞自发性钙火花频率。

Objective To identify the effect of high glucose on the structure of transverse tubule（t-tubule） and expression of junctophilin-2（JP-2） in mouse cardiomyocytes and to explore the potential mechanism of high glucose-induced cardiac damage. Methods Mouse ventricular myocytes were collected and cultured and divided into two groups with treatment of high glucose and low glucose, respectively. Laser confocal microscopy imaging was used to record the calcium sparks and the structure of t-tubule in both groups. The expression of JP-2 in ventricular myocytes was detected by western blotting and immunofluorescence. Results High glucose significantly increased the frequency of spontaneous calcium sparks and the destruction of t-tubules in ventricular myocytes. In addition, high glucose decreased the expression of JP-2 in t-tubules. Conclusions High glucose can damage the structure of t-tubule by decreasing the expression of JP-2, thereby increasing the frequency of spontaneous calcium sparks in ventricular myocytes.