TPN171H alleviates pulmonary hypertension via inhibiting inflammation in hypoxia and monocrotaline-induced rats

Pulmonary hypertension (PH) is a progressive and life-threatening disease with poor prognosis despite many advances in medical therapy over the past 20 years. Novel therapies which target on the underlying pathology of PH are still urgent to be met. TPN171H is a recently found new compound that exhibits potent pharmacological effects in PH via inhibiting phosphodiesterase type 5 (PDE-5). However, as one icariin derivative, the anti-inflammatory effects of TPN171H for treating PH are not clear. The present study was designed to investigate the therapeutical effect of TPN171H against inflammation in PH and reveal the underlying mechanism. Hypoxia and monocrotaline (MCT)-induced PH rat models were established, which were treated by oral administration of TPN171H (5, 25 mg/kg/d) or sildenafil (25 mg/kg/d). The right ventricle systolic pressure (RVSP), right ventricle hypertrophy index (RVHI) and vascular remodeling were measured. The results suggested that TPN171H significantly reduced RVSP and RVHI, and reversed pulmonary vascular remodeling in rats with both models. Furthermore, in in vivo and in vitro research, our data suggested that TPN171H remarkably suppressed cathepsin B-mediated NLRP3 inflammasome activation, which may contribute to its therapeutical function for PH.