The result demonstrated that the protein expressions of Snail, Zeb1, fibronectin, Vimentin, TGF‐ß, p‐Smad2 and p‐Smad3, seven indices of endMT biomarkers, were significantly increased in MCT group than in the SC group, and were significantly reversed in MCT‐PTU group, suggesting PTU therapy may be potential for the PAH patients. This evidence concerns the gene SNAI1 and pulmonary arterial hypertension.