Cardiovascular and neuroimmune adaptations to enalapril and exercise training: A comparative study in male and ovariectomized female spontaneously hypertensive rats

Antihypertensive drug and exercise training are commonly prescribed to treat arterial hypertension. However, there is a considerable gap in understanding how physiological mechanisms of male and female adapt to the combination of these approaches. Therefore, we focused to investigate sexual differences in cardiovascular, autonomic, inflammation and systemic oxidative stress adaptations in male and OVX female ovariectomized spontaneously hypertensive rats (SHR) treated with enalapril associated with moderate-intensity concurrent exercise training. Enalapril (3 mg/kg, diluted in drinking water) and exercise training (3 days/week, moderate intensity) was carried out for 8 weeks. Blood pressure (BP), heart rate (HR) and its variabilities were assessed. Serum and plasma were used for inflammatory and oxidative stress analyses. Enalapril, associated or not with exercise training, induced a reduction in diastolic and mean BP in both sexes; however, only the OVX female groups showed a reduction in systolic BP, as well as resting bradycardia. Both sexes showed improvements in BP and HR variability following the treatments; however, improvement in SD2/SD1 ratio, which indicates how much the heartbeats occur at irregular intervals, and in variance of systolic BP were observed only in trained groups. A higher spontaneous baroreflex sensitivity, as well as reduced IL-6/IL-10 were found only in the trained groups. Increased IL-10 was observed in male trained group (vs. other groups). Finally, combination enalapril and exercise training reduced systemic pro-oxidants such as NADPH oxidase and hydrogen peroxide. The findings of our study showed that OVX female SHR, after ovarian hormone deprivation, presented more pronounced effects on hemodynamics, BP variability, and anti-inflammatory profile than hypertensive males with the combination of treatments.

Background

Researchers are investigating how the body responds differently in males and females. These differences are also evident when examining how pharmacological and non-pharmacological approaches help the body control arterial hypertension. This study aimed to investigate how drug medication combined with exercise affects the heart's ability to self-regulate and how it relates to immune and oxidant defense, with a focus on differences in male and ovariectomized (OVX) female adaptations.

Methods

The study was conducted using hypertensive male and OVX female rats, allocated into: a) sedentary, b) enalapril, or c) enalapril plus exercise groups, totaling six groups (3 males and 3 OVX females, respectively). Enalapril (3 mg/kg/day) and exercise (aerobic and resistance exercises) were prescribed for eight weeks. The effects on blood pressure control, serum, and plasma were assessed.

Results

Although both males and OVX females showed improvements in blood pressure after medication, combined or not with exercise, OVX females had better control of blood pressure and heart rhythm regulation. Furthermore, including an exercise program during medication treatment improved immune defense in OVX females only, as well as the levels of key enzymes involved in the process of organ damage development in both sexes.

Conclusion

OVX female rats benefited more from the combination of medication and exercise compared to male rats. This suggests that OVX females may experience additional health benefits from the combination of antihypertensive approaches, highlighting the importance of understanding how exercise impacts the body differently in males and OVX females, which could contribute to better long-term disease management.