Fig. 8. Expressions of ERA, Bcl-2, collagen 1, and collagen 3 according to treatment timing by low-dose treatment of hUCB-MSCs in MCT-induced PAH rats. (A) Protein expression of ERA was significantly increased in the lung tissues of M group compared with C group at week 4. (B) Protein expression of Bcl-2 was significantly decreased in the lung tissues of UF groups compared with M group at week 4. (C) Collagen 1 in the heart tissues was significantly increased in M group compared with C group at week 4. (D) Collagen 3 in the heart tissues was significantly decreased UD and UF group compared with M group at week 4. ^*p<0.05, compared with C, ^†p<0.05, compared with M. MCT, monocrotaline; PAH, pulmonary arterial hypertension; hUCB-MSCs, human umbilical cord blood derived mesenchymal stem cells; C, control group; M, monocrotaline group; UD, early treatment group of low dose hUCB-MSCs at day 1; UE, dual transfusion group of low dose hUCB-MSCs at day 1 and week 1; UF, reversal treatment group of low dose hUCB-MSC at week 1; Dual, twice-transfusion of hUCB-MSCs group; ERA, endothelin receptor A; Bcl-2, B-cell lymphoma 2; GAPDH, glyceraldehyde 3-phosphate dehydrogenase.