The effect and mechanism of swimming exercise on left ventricular remodeling in spontaneously hypertensive rats / 中华物理医学与康复杂志

ABSTRACT

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 eightweek-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 Ⅱ (ANG Ⅱ) 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-α (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-1 βand 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.