Table 1.
Primers used in quantitative real-time PCR assays.
Fig 1.
Effects of 4-PBA on mean pulmonary arterial pressure (mPAP) and right ventricular pressure (RVSP) in a rat model of MCT-induced pulmonary arterial hypertension.
(A) mPAP (mmHg) observed in rats in the NORMAL (n = 12), PAH (n = 6), REV (n = 8) and PRE (n = 8) groups. (B) RVSP (mmHg) observed in rats in the NORMAL (n = 12), PAH (n = 6), REV (n = 9) and PRE (n = 8) groups. Compared to the MCT-induced PAH model group, significant changes in mPAP and RVSP were observed for all other groups. *p < 0.05; **p < 0.01; ***p < 0.001.
Fig 2.
4-PBA attenuates pulmonary arterial remodeling.
Lung histology examples from the NORMAL group (A), PAH group (B), REV group (C) and PRE group (D) are shown. In the NORMAL group, the thickness of the pulmonary arterioles was normal and the distribution of smooth muscle cells was even. There was no congestion in the lumen of the pulmonary artery. In the PAH group, significantly increased pulmonary arterial wall thickness, luminal congestion, interstitial lung hemorrhage and increased inflammatory cell infiltration were observed, (marked by arrows). In the REV group, the MCT-induced pulmonary arterial wall thickening and inflammatory cell infiltration were significantly attenuated by 4-PBA. In the PRE group, compared with the PAH group, significantly decreased pulmonary arterial wall thickness, no luminal congestion, and less inflammatory cell infiltration were observed. Scale bars = 50 μm.
Fig 3.
4-PBA reverses and prevents pulmonary arterial and right ventricular remodeling in a rat model of MCT-induced PAH.
The percent medial wall thickness (MWT%, A), the ratio of vascular wall area (WA) / total vascular area (WA%, B), the ratio of vascular lumenal area (VA) / total vascular area (luminal erea, LA%, C) and the right ventricular hypertrophy index (RVHI%, D) were examined in the NORMAL, PAH, REV and PRE groups (n = 10 for each group). Compared to the PAH group, significantly lower MWT%, WA% and RVHI% values were observed in the other groups (A, B and D), while significantly higher LA% values were observed (C). ***p < 0.001.
Fig 4.
Effects of 4-PBA on gene expression levels in the main branches of the ER stress signaling pathway in MCT-induced PAH lungs.
(A) Relative expression levels of three representative genes in the ATF6 branch of ER stress. ATF6, activating transcription factor-6; GRP78, 78-kDa glucose-regulated protein; GRP94, 94-kDa glucose-regulated protein. (B) Relative expression levels of three representative genes in the PERK branch of ER stress. PERK, PKR-like ER kinase; CHOP, transcription factor C/EBP homologous protein; BCL-2, apoptosis regulator Bcl-2. C. Relative expression levels of three representative genes of the IRE-1 branch of ER stress. IRE-1, inositol-requiring enzyme-1. In each group, n = 10. For each gene, the expression level of the NORMAL group was set to 1. Compared to the PAH group, significant changes in expression levels were found. *p < 0.05; **p < 0.05; ***p < 0.001.
Fig 5.
Effects of 4-PBA on protein levels in the ATF6 and PERK branches of ER stress signaling in MCT-induced PAH lungs.
(A) Western blots of proteins in the ATF6 and PERK branches of ER stress. β-actin (ACT) was used as a housekeeping protein. (B) Relative band intensities of three proteins in the ATF6 branch of ER stress (compared to ACT). (C) Relative band intensities of three proteins in the PERK branch of ER stress (compared to ACT; n = 3 for each group). Statistical analysis was performed exactly as in Fig 4.