Salidroside enhances NO bioavailability and modulates arginine metabolism to alleviate pulmonary arterial hypertension.

Background: Salidroside (SAL), derived from Rhodiola, shows protective effects in pulmonary arterial hypertension (PAH) models, but its mechanisms are not fully elucidated.

Objectives: Investigate the therapeutic effects and the mechanism of SAL on PAH.

Methods: Monocrotaline was used to establish a PAH rat model. SAL's impact on oxidative stress and inflammatory responses in lung tissues was analyzed using immunohistochemistry, ELISA, and Western blot. Untargeted metabolomics explored SAL's metabolic regulatory mechanisms.

Results: SAL significantly reduced mean pulmonary artery pressure, right ventricular hypertrophy, collagen deposition, and fibrosis in the PAH rats. It enhanced antioxidant enzyme levels, reduced inflammatory cytokines, and improved NO bioavailability by upregulating endothelial nitric oxide synthase (eNOS), soluble guanylate cyclase (sGC), cyclic guanosine monophosphate (cGMP), and protein kinase G (PKG) and decreases the expression of endothelin-1 (ET-1). Metabolomics indicated SAL restored metabolic balance in PAH rats, particularly in arginine metabolism.

Conclusions: SAL alleviates PAH by modulating arginine metabolism, enhancing NO synthesis, and improving pulmonary vascular remodeling.