Therefore, we infer that CTGF may participate in pulmonary arteries remodeling and apoptosis in MCT-induced PAH and PCPA may inhibit pulmonary artery remodeling and induce apoptosis through suppressing the TPH-1, SR-1B, which influence CTGF and the downstream signaling pathways. Here, TPH1 is linked to pulmonary arterial hypertension.