Title : Effect of corticosterone on blood pressure in SHR ovariectomized rats
Abstract:
Introduction: Hypertension (HTA) is a major risk factor for cardiovascular diseases. Spontaneously hypertensive rats (SHR) serve as a genetic model that mimics the characteristics of human disease. Female SHR generally exhibit lower blood pressure (BP) than their male counterparts, primarily due to the protective effects of estrogens. Ovariectomy (OVX), which reduces estrogen, leads to increased BP. Corticosteroids are known to potentiate the effects of angiotensin II and upregulate the AT1 receptors, thereby influencing BP regulation.
Objective: To evaluate the effect of corticosterone on BP in SHR ovariectomized rats.
Methods: Six-month-old SHR and WKY-Kyoto (WKY) rats, both male and female, were used. Female rats were divided into ovariectomized and non-ovariectomized groups. An additional group of 12-month-old female SHR was included to evaluate age-related changes. Corticosterone (5 mg/kg, i.p.) was administered once, and BP was measured using tail-cuff plethysmography (IITC Life Science, MRBP System). Data were analyzed using one-way ANOVA followed by Tukey’s post hoc test (p<0.05).
Results: OVX significantly increased systolic blood pressure (SBP) in SHR (SHR-OVX: 154 ± 2 mmHg vs. SHR: 144 ± 5 mmHg, p<0.05), without affecting mean blood pressure (MAP) or diastolic blood pressure (DBP). No significant changes were observed in WKY rats. OVX rats exhibited a 12% increase in body weight, similar to age-related weight gain observed in 12-month-old SHR. Corticosterone administration did not modify BP in any group.
Conclusion: Ovariectomy elevated SBP in SHR, while corticosterone administration had no effect on BP in any of the groups.
