低强度游泳运动对自发性高血压大鼠左心室重构的影响

The effect and mechanism of swimming exercise on left ventricular remodeling in spontaneously hypertensive rats

目的观察运动训练对自发性高血压大鼠（SHR）左心室重构的影响。方法将20只8周龄雄性SHR按随机数字表法分为高血压对照组和高血压运动组，每组10只；另选取8周龄健康雄性Wistar大鼠10只作为正常对照组。高血压运动组大鼠进行为期12周低强度的无负重游泳运动，每周6次、每次60min；高血压对照组和正常对照组大鼠仅常规饲养，不进行任何训练。3组大鼠每周测量1次血压，运动12周后ELISA检测血清中去甲肾上腺素（NE）和血管紧张素Ⅱ（ANGⅡ）水平。组织学检测左心室心肌形态学的变化及心肌细胞直径，天狼星红染色检测左心室胶原沉积，半定量逆转录-聚合酶链反应（RT—PCR）和免疫印迹检测重塑的左心室心肌组织中肿瘤坏死因子-α（TNF—α），白介素-6（IL-6），白介素-1β（IL-1β）和转化生长因子β1（TGF—β1）的表达。结果入组12周后，高血压运动组的收缩压和舒张压分别为（150．6±6．7）mmHg和（91．6±7．1）mmHg，与组内入组后当天和高血压对照组入组12周后比较，均显著下降（P〈0．05），但与正常对照组比较，差异仍有统计学意义（P〈0．05）。入组12周后，高血压运动组的LVW／BW、NE和ANGⅡ水平显著低于高血压对照组大鼠（P〈0．05），但仍显著高于正常对照组大鼠（P〈0．05）；高血压运动组和高血压对照组大鼠的左心室心肌细胞直径均显著大于正常对照组（P〈0．05），而高血压对照组的左心室心肌细胞直径亦大于高血压运动组（P〈0．05）；高血压运动组和高血压对照组大鼠的胶原容积分数（CVF）值均显著高于正常对照组（P〈0．05），而高血压对照组的CVF值亦显著高于高血压运动组（P〈0．05）。入组12周后，高血压运动组和高血压对照组重塑的左心室心肌中TNF-α，IL-6，IL-1β和TGF—β1的mRNA及蛋白的表达均显著高于正常对照组（P〈0．05）；高血压运动组重塑的左心室心肌中TNF—α，IL-6，IL-1β和TGF—β1的mRNA及蛋白的表达均显著低于高血压对照组（P〈0．05）。结论游泳运动可显著降低SHR的血压水平，改善SHR大鼠的左心室重构，其改善左心室重构的机制不仅与降低交感神经与肾素一血管紧张素系统的活性有关，还与降低细胞因子TNF—α，IL-6，IL-1β和TGF—β1的表达有关。

Objective To investigate the effects of swimming exercise training on left ventricular （LV） remodeling and its possible mechanism in spontaneous hypertensive rats （SHR） . Methods Twenty eight-week-old male SHRs were divided into SHR control （SC） group and SHR exercise training （ST） group, with 10 rats in each group. Ten eight-week-old male Wistar rats were used as normal control （WC） group. The ST group was subject to 60-min moderate swimming exercise without loading once daily, 6 times a week, for a total of 12 weeks; while the SC and WC group had no special intervention. The blood pressure was examined once weekly. After 12 weeks, the norepinephrine （NE）and serum angiotonin （ANG 11 ） levels were determined by ELISA. The LV hypertrophy was assessed by analysing the ratio of LV weights to body weights （LVW/BW） and cardiomyocyte diameter. The collagen deposited in LV was detected by sirius red staining. The expressions of tumor necrosis factor-or （ TNF-α ） , interleukin-6 （ IL-6 ） , interleukin-1β（ IL-1β ） and transforming growth factor-β1 （TGF-β1） in LV were determined by semi-quantitative real time-polymerase chain reaction （RT-PCR） and Western blotting. Results After 12 weeks, the blood pressure, serum NE and ANG Ⅱ levels, LVW/BW ratio, cardiomyocyte diameter and collagen volume fraction （CVF） increased significantly in SC group compared with WC group; while those in ST group decreased significantly. In addition, in ST group the mRNA and protein expressions of TNF-α, IL-6, IL-1β and TGF-β1 also decreased significantly. Conclusions The swimming exercise could reduce the blood pressure of SHR and improve LV remodeling. This effect was mediated not only by improving the hemodynamics, but also by decreasing sympathetic nerve and renin-angiotensin system （RAS） activities, decreasing the gene expressions of cytokines. The swimming exercise may be an effective strategy for improving LV remodeling in hypertension.