Exercise attenuates perivascular adipose tissue sympathetic innervation and regulates arterial stiffness in obese rats

Background/objectives: This study was designed to investigate the involvement of sympathetic innervation within perivascular adipose tissue (PVAT) during exercise regulating arterial stiffness in obese rats, and the potential neuro-vascular mechanism. Methods: Rats were subjected to normal diets control (NC), normal diets exercise (NE), high-fat diets control (HC), and high-fat diets exercise (HE) groups. 8-week exercise was performed using the treadmill. Arterial stiffness was determined by the elastic modulus. Sympathetic nerve distribution, angiotensin II (Ang II), angiotensin type 1 receptor (AT1R), actin, and collagen were observed. Circulating noradrenaline (NA), β3-adrenergic receptor (β3-AR), phosphorylation-AMPKα (p-AMPKα), and adiponectin in PVAT were quantified. Results: After exercise, thoracic aorta elastin elastic modulus (EEM) and α-smooth muscle actin (α-SMA) levels were significantly increased (p < 0.05, HE vs. HC); collagen elastic modulus (CEM), collagen II and collagen III had no statistical significance among groups. Moreover, circulating NA and sympathetic nerve density within thoracic aorta PVAT was significantly decreased (p < 0.05, HE vs. HC) by exercise. Additionally, levels of Ang II and AT1R in thoracic aorta with PVAT were significantly reduced (p < 0.05, HE vs. HC) by exercise. The p-AMPKα was significantly increased (p < 0.05, NE vs. NC, HE vs. HC) by exercise, but β3-AR and adiponectin had no statistical significance among groups. Conclusions: Treadmill exercise attenuated sympathetic innervation in PVAT and was associated with reduced arterial stiffness in obesity. This beneficial neuro-vascular changes were accompanied by reductions in Ang II and AT1R expression in PVAT, suggesting a possible role for local renin-angiotensin signalling in exercise-induced vascular protection.