Abstract:Objective The aim of this study is to investigate the effect and the underlying mechanisms of glycyrrhizin on pulmonary vascular remodeling and right heart remodeling in rats with pulmonary arterial hypertension (PAH). Methods The PAH rat model was established by intraperitoneal injection of monocrotaline (MCT). After 2 weeks of MCT modeling, the rats were given 60 mg/kg and 20 mg/kg glycyrrhizin for 2 weeks. Right ventricular systolic pressure (RVSP), pulmonary vascular remodeling and right heart remodeling were observed. The plasma levels of cyclic guanosine phosphate (cGMP) and pulmonary tissue protein kinase G (PKG) were measured. Results The results showed that both 60 and 20 mg/kg glycyrrhizin decreased RVSP and RVHI in MCT-induced PAH rats, and increased the protein expression levels of cGMP and PKG (P<0.01 or 0.05). Conclusion Glycyrrhizin has certain effect on pulmonary vascular remodeling and right heart remodeling in PAH rats.