Abstract

Background: Silibinin is a polyphenolic compound that could modulate estrogen receptor activation. Vascular dysfunction is considered a key initiator in atherosclerosis and may occur in the postmenopausal period. This manuscript compares estrogen and silibinin's impacts on factors that change endothelial function in ovariectomized (OVX) rats. Methods: 32 female Wistar rats were subdivided into control; OVX; OVX + estrogen (1 mg/kg/day); and OVX + silibinin (50 mg/kg/day) groups. After the experimental period, lipid profile, atherogenic indices, and histopathology of endothelium were monitored. The vascular oxidative stress, adhesion molecules, inflammatory cytokine levels, nitric oxide (NO), angiotensin-II (Ang-II), and endothelin-1 (ET-1) were also analyzed. Results: Silibinin treatment, similar to estrogen, significantly normalized the adverse changes of OVX on vascular function, including improved lipid profile and oxidative stress, increased endothelial nitric oxide synthase (eNOS) expression, diminished inflammatory status, and reduced adhesion molecule levels, ET-1 and Ang-II substances. Our findings also revealed that the administration with estrogen or silibinin resulted in a normal endothelium layer in the aorta tissues of OVX rats. Conclusion: Estrogen and silibinin have similar effects in improving vascular function. These treatments' protective impacts on vasculature indicate their potential benefits on the cardiovascular system in the postmenopausal period.