跑台运动通过抑制WNK2表达改善糖尿病心肌病的心室重构

Treadmill exercise inhibited WNK2 to improve cardiac remodeling in diabetic cardiomyopathy

目的:明确运动训练延缓糖尿病诱导的心肌损伤并阐明WNK2在其中的作用。方法:雄性db/db小鼠和C57BL/6小鼠(作为对照)普通饲料喂养,根据是否参与跑台训练各分成两组,跑台组训练10周。采用心超评估小鼠心功能,留取心肌组织进行伊红苏木素(HE)染色、马松(Masson)和麦胚凝集素(WGA)染色,并提取心肌mRNA、蛋白进行实时荧光定量聚合酶链反应(RT-q PCR)和蛋白质印迹(Western blot)检测。H9C2心肌细胞系予以高糖(33 mmol/L)刺激并WNK2抑制剂(WNK463)预处理后检测各组细胞肥大[肌球蛋白重链(MyHC)和心房钠尿肽(ANP)]、纤维化[包括基质金属蛋白酶9(MMP-9)、I型胶原蛋白(COL-I)和转化生长因子β(TGF-β)]指标。结果:与对照组小鼠相比,db/db组小鼠心脏明显肥厚,纤维化增加,心肌收缩能力显著下降,心脏组织WNK激酶(WNK2)表达显著增加,差异有统计学意义(P<0.05);经10周跑台运动后,心肌肥厚和胶原纤维沉积得到逆转,心收缩功能改善,并且WNK2表达降低,差异有统计学意义(P<0.05)。利用WNK463处理高糖刺激的心肌细胞,抑制WNK2表达,可以有效降低H9C2细胞肥大(MyHC和ANP)和纤维化(MMP9、COL-I和TGF-β)指标,差异有统计学意义(P<0.05)。结论:运动训练通过抑制WNK2表达来改善糖尿病心肌病的心肌肥大及纤维化。

Objective: To investigate the effect of exercise training on preventing diabetic cardiomyopathy and to determine the role of WNK2 in high-glucose induced cardiomyocytes. Methods: Male db/db mice and C57BL/6 mice(as control) were fed a regular diet for 10 weeks, then began running exercise or remained sedentary for 10 weeks. After that, cardiac function was assessed by echocardiography, and heart tissues were collected for further measurements including Hematoxylin-Eosin(HE) staining, Masson’s staining, wheat germ agglutinin(WGA) staining, real-time quantitative polymerase chain reaction(RT-qPCR) and Western blot. In addition, after pretreatment with WNK463(a WNK2 inhibitor) in high glucose-induced H9C2 cardiomyocytes, the indicators of hypertrophy, fibrosis of cells, collagen type I(COL-I) and transforming growth factor β(TGF-β) were tested.Results: Compared with the control, the heart of db/db mice showed cardiac hypertrophy and fibrosis, reduced cardiac function and increased WNK2 levels, with statistical difference(P<0.05). After 10 weeks of treadmill exercise, cardiac hypertrophy and collagen deposition were reversed, cardiac systolic function was improved, and WNK2 expression was decreased, showing significant difference(P<0.05). Mechanistically, WNK2 inhibition prevented the expression of myosin heavy chain(MyHC) and atrial natriuretic peptide(ANP), as well as fibrosis reflected by matrix metalloprotein-9(MMP9), collagen-I(COL-I) and transforming growth factor-β(TGF-β)in high glucose-stimulated cardiomyocytes, indicating that the suppression of WNK2 could reduce hypertrophy and fibrosis of cells. Conclusion: Running exercise limits cardiac hypertrophy, fibrosis and reverses cardiac dysfunction in diabetic cardiomyopathy by inhibiting WNK2 upregulation.