Effect of aerobic training on the capillary and arteriolar remodeling in heart and skeletal muscle of hypertensive rats

Abstract

We evaluated if aerobic training improves blood pressure and if determine capillary and arteriolar remodeling in heart and skeletal muscle of hypertensive rats.We used SHR and WKY male rats submitted or not to aerobic training (AT, 1hr, 5 times per week, in treadmill). Rats were trained for 1, 2, 4, 8 and 12 weeks or kept sedentary for 0 and 12 weeks (n=8/group). At the end of each time, artery was catheterized for mean arterial pressure (MAP) and heart rate (HR) measurements. Heart, soleus and temporalis skeletal muscles were harvested for histologic evaluation, with capillary density and arteriolar wall/lumen ratio measurements.Both SHR and WKY improved physical performance after 12 weeks of AT (S0:1.02±0.3 vs 1.62±0.4, T12:1.92±0.4 vs 2.40±0.4km/h, WKY vs. SHR). AT induced a rest bradycardia in WKY (326±4 to 294±3bpm), and in SHR (385±7 to 357±2bpm). Only SHR reduced MAP after AT (174±2 to 164±1mmHg). AT decreased arteriolar wall/lumen ratio in SHR in the second week of training in soleus (−0.23±0.03μm), and in the fourth week in heart (−0.06±0,02 μm) and temporalis (−0.09±0.02μm). AT also induced fast (week 1) capillary increase in the heart of WKY (+31.1%) and SHR (+202.8%), and in soleus of WKY (+22%) and SHR (+110%).The data indicates that AT induced beneficial vascular remodeling after hemodynamic adjusts, improving arteriolar wall/lumen ratio and capillary density, more pronounced in hypertensive rats.