Inhibition of GTPase Rac1 expression by vitamin D mitigates pressure overload-induced cardiac hypertrophy

[Display omitted] 1, 25-dihydroxy Vitamin D3 (VitD) attenuates left ventricular hypertrophy (LVH), but the mechanisms remain to be portrayed in-depth. The small GTPase Rac1 plays a pivotal role in cardiovascular pathology, especially LVH. Here, we tested whether VitD exerts its anti-LVH effects by counteracting the small GTPase Rac1 expression. In Wistar rats, pressure overload-induced LVH was created by abdominal aortic banding. The animals were intraperitoneally administered VitD (0.1 µg/kg/d). Blood pressure was measured via carotid artery cannulation. Real-time RT-PCR and Western blotting were performed to assess the mRNA and protein expression, respectively. Myocardium was stained for determination of cardiomyocytes area and fibrosis. Lipid peroxidation levels and the activities of antioxidant enzymes were measured in left ventricular tissue. VitD significantly reduced hypertrophy markers (blood pressure, heart-to-body weight ratio, cardiomyocytes area, fibrosis as well as atrial and brain natriuretic peptides mRNA levels) compared to untreated groups (P