Effects of Long-Term Aerobic Exercise on Perivascular Adipose Tissue Function and Akt/eNOS/NO Pathway in Obese Rats

Background Perivascular adipose tissue (PVAT) in obesity critically contributes to vascular dysfunction, which might be restored by long-term exercise. Protein kinase B/nitric oxide synthase/nitric oxide (Akt/eNOS/NO) down-regulation within PVAT might be involved in the impaired anti-contractile function of arteries. Therefore, the present study evaluated the effect of long-term aerobic exercise on PVAT function and the potential regulator during this process. Methods Male Sprague Dawley rats were divided into normal diet control group (NC), normal diet exercise group (NE), high-fat diet control group (HC), and high-fat diet exercise group (HE) ( n = 12 in each group). Upon the establishment of obesity (20 weeks of high-fat diet), exercise program was performed on a treadmill for 17 weeks. After the intervention, circulating biomarkers and PVAT morphology were evaluated. Vascular contraction and relaxation were determined with or without PVAT. Production of NO and the phosphorylations of Akt (Ser473) and eNOS (Ser1177) within PVAT were quantified. Results Metabolic abnormalities, systemic inflammation, and circulating adipokines in obesity were significantly restored by long-term aerobic exercise ( P < 0.05). The anti-contractile effect of PVAT was significantly enhanced by exercise in obese rats ( P < 0.05), which was accompanied by a significant reduction in the PVAT mass and lipid droplet area ( P < 0.05). Furthermore, the production of NO was significantly increased, and phosphorylation levels of Akt (Ser473) and eNOS (Ser1177) were also significantly promoted in PVAT by long-term aerobic exercise ( P < 0.05). Conclusion Long-term aerobic exercise training restored PVAT morphology and anti-contractile function in obese rats, and enhanced the activation of the Akt/eNOS/NO signaling pathway in PVAT.