Anti-contractile effects of perivascular adipose tissue in thoracic aorta from rats fed a high-fat diet: role of aerobic exercise training
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The aim of the present study was to evaluate the effects of aerobic exercise training on perivascular adipose tissue (PVAT) function in thoracic aorta from rats fed a high-fat diet. Aortic vascular reactivity was performed in sedentary (SD), trained (TR), sedentary high-fat diet (SD-HF), and trained high-fat diet (TR-HF) male Wistar rats in the absence (PVAT−) or in the presence (PVAT+) of thoracic PVAT. We also measured circulatory concentrations of leptin and tumour necrosis factor alpha (TNF-α), as well as the protein expressions of TNF-α receptor 1 (TNFR1) and inducible nitric oxide synthase (iNOS) on PVAT. In the SD-HF group, the body weight, epididymal fat pad, thoracic PVAT, circulatory triglycerides, insulin, leptin and TNF-α were increased when compared with the SD group, whereas exercise training reduced these values in TR-HF group. The relaxing response curves to acetylcholine and sodium nitroprusside were not modified by either intervention (high-fat diet or exercise training) or the presence of PVAT. The presence of PVAT had an anti-contractile effect in response to serotonin in all groups. In SD-HF group, the increased magnitude of anti-contractile effects was in parallel with an up-regulation of iNOS protein expression in PVAT without alteration in TNFR1. Exercise training was effective in normalizing the vascular reactivity in rings PVAT+ and in reducing the iNOS protein expression. Exercise training prevented the PVAT–induced alteration in thoracic aorta from rats fed a high-fat diet.