Vanillic Acid Alleviates Right Ventricular Function in Rats With MCT-Induced Pulmonary Arterial Hypertension

This study examined the molecular processes behind the effects of vanillic acid (VA) on right ventricular (RV) hypertrophy and function in rats with monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). There were 40 male Sprague‒Dawley (SD) rats that were separated into 4 groups: Control, PAH, MCT + VA (50 mg/kg/d), and MCT + VA (100 mg/kg/d). Male SD rats were injected with MCT once under the skin to create the PAH model (40 mg/kg). RV morphological properties were evaluated using Masson and hematoxylin and eosin (H&E) staining. Echocardiography was used to evaluate RV functioning and right ventricle–pulmonary artery (RV-PA) coupling. In addition, Rho-associated protein kinase (ROCK) pathway-related factors were evaluated using Western blotting. Enzyme-linked immunosorbent assay (ELISA) was used to detect inflammatory markers as well as atrial natriuretic peptide (ANP) and brain-type natriuretic peptide (BNP) in the blood of PAH rats. As a result, VA effectively reduced the development of RV cardiomyocyte hypertrophy and fibrosis in PAH rats; levels of ANP, BNP, and inflammatory markers in the blood of PAH rats were also significantly decreased by VA intervention. Additionally, VA enhanced RV functioning and RV-PA coupling in PAH rats. In response to VA, the expression of proteins related to the ROCK pathway (ROCK1, ROCK2, NFATc3, P-STAT3, and Bax) was downregulated, whereas Bcl-2 expression was elevated. This study found that VA could attenuate RV remodeling and improve RV-PA coupling in PAH rats. RV remodeling and dysfunction may be linked to the dysregulation of the ROCK pathway, and the protective action of VA on RV function may be due to a block in the ROCK signaling pathway or its downstream signaling molecules.