Beneficial effects of swimming and pomegranate juice in rats with hypertension: A possible role of serum adropin

Hypertension, characterized by persistent and uncontrolled high blood pressure, is one of the most common significant causes of mortality worldwide. Lifestyle modifications such as exercise and antioxidant intake have showed beneficial effects on hypertensive conditions. Adropin and endothelin-1 (ET-1) have important vasoregulatory functions in the endothelium. However, the underlying mechanisms linking exercise- and/or antioxidant intake-mediated improvement of hypertension are not fully understood. In this study, it was hypothesized that swimming exercise and pomegranate juice (PJ) (as an antioxidant) administration might have protective effects on hypertension development and possible involvements of serum adropin and ET-1. To test the hypothesis, the rats with hypertension, induced by Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME), were subjected to swimming exercise and received PJ for 8 weeks. Weekly systolic and diastolic pressures, serum adropin, and ET-1 levels, and oxidant/anti-oxidant parameters in various tissues were measured. The obtained data show that swimming exercise leads to complete protection against hypertension within the 8-week duration whereas the PJ administration causes an ameliorative effect. In addition, the combination of swimming exercise and PJ administration do not have additive effects in the protection of hypertension. Notably, the 8-week swimming exercise restores the diminished serum adropin levels in rats with hypertension to the control levels. Serum adropin levels significantly correlated with systolic and diastolic pressures, depending on swimming exercise, but not PJ administration. Serum ET-1 levels inconsistently fluctuate in response to L-NAME, swimming exercise, and PJ intake. In addition, swimming exercise and/or PJ administration lead to a complete normalization in liver MDA levels of rats with hypertension, while these interventions cause slight or no improvements in levels of SOD, CAT, and GSH in the heart, liver, and kidney. In conclusion, 8-week swimming exercise modulates hypertension possibly by influencing adropin levels and oxidative stress.