20-Hydroxyecdysone attenuates cardiac remodeling in spontaneously hypertensive rats.

BACKGROUND: Ecdysteroids, a group of steroid hormones found in insects and many plants, have been shown to prevent various changes in mammalian tissues after female sex hormone deprivation.

PURPOSE: To examine whether an ecdysteroid, 20-hydroxyecdysone (20-HE), exhibits regulatory or protective roles in the cardiovascular system.

STUDY DESIGN/METHOD: Blood pressure and cardiac function were evaluated in spontaneously hypertensive rats (SHR) during and after daily treatment with 20-HE for six weeks.

RESULTS: The progressive increase in systolic blood pressure with age in SHR rats was significantly lower in animals treated with either 5 or 10mg/kg body weight of 20-HE. However, treatment with 20-HE did not diminish the increase in diastolic pressure. Echocardiography after six weeks of treatment demonstrated that the left ventricular chamber of SHR rats treated with 20-HE was smaller than that of SHR controls, while contractility was not affected by 20-HE. Histological images also demonstrated a decrease in cardiomyocyte cross-sectional area in 20-HE treated groups. Interestingly, treatment with 20-HE caused a shift in cardiac myosin heavy chain towards more β-isoforms. SHR rats treated with 20-HE also exhibited a decrease in seminal vesicular weight and an increase in testicular weight, especially at a dose of 10mg/kg body weight. This finding suggests a possible anti-androgenic effect of 20-HE.

CONCLUSION: Our finding reveal that 20-HE has a beneficial effect on reducing blood pressure and consequently preventing dilated cardiac hypertrophy in SHR rats.