(A) Representative image of HE staining, which was performed to quantify the medial wall thickness of the distal pulmonary arterioles (original magnification, ×200). (B) Representative image of immunohistochemical staining of α-SMA, which reflects the muscularization of distal pulmonary arterioles (original magnification, ×200). Summarized data of HE staining (C) and average optical density of α-SMA (D). Medial wall thickness was calculated by the ratio of mean vessel thickness (μm) to mean outer vessel thickness (μm). (E) Representative Western blot and relative quantification analysis of xbp1s and Ddit3 protein expression in rodent PH model lung tissues. Data are represented as the mean ± SD, n=8–10. ns, no significance, ****P<0.0001.