Objective: To investigate the effect of Yiqi Wenyang Huoxue Huatan Fang (YWHHF) on alleviating hypoxia-hypercarbia pulmonary hypertension by inhibiting endothelial-mesenchymal transition (EndoMT) via BMP-7/Smads pathway.
Methods: Fifty male healthy SD rats of clean grede, weighting (180~220) g, were randomly divided into 5 groups (n=10):normoxia group (N), hypoxia-hypercarbia group (HH); YWHHF high dose group (YH), middle dose group (YM) and low dose group (YL). The rats in N group were kept in normal oxygen environment, the remaining four groups were intermittently exposed to hypoxia-hypercarbia environment (9%~11% O2, 5%~6% CO2) for 4 weeks, 6 days a week, 8 hours per day. The rats in YH, YM, YL groups were received YWHHF gavage in a dosageof 0.6, 0.3, 0.15g/kg respectively (3 ml/kg),the rats in N and HH groups were received equal volume of normal saline. After 4 weeks, the mean pulmonary arterial pressure(mPAP) was detected,the right ventricular free wall and left ventricle plus ventricular septum were isolated to determine the right ventricular hypertrophy index. Lung ultrastructural changes were surveyed under an electronic microscopy, the changes of pulmonary artery structure surveyed by immunofluorescence, the mRNA levels of alpha-smooth muscle actin (α-SMA)、platelet endothelial cell adhesion molecule-1 (CD31)、bone morphogenetic protein-7 (BMP-7)、drosophila mothers against decapentaplegic protein1/5/8 (Smad1/5/8) were detected by RT-PCR, and the protein levels of α-SMA、CD31、BMP-7、p-Smad1/5/8 and Smad1/5/8 were detected by Western blot.
Results: Compared with N group, mPAP and the right ventricular hypertrophy index were increased,some significant injuries also were discovered under microscopic observation,the mRNA and protein expression of α-SMA was increased, and the mRNA expressions of CD31、BMP-7、Smad1/5/8 were decreased in the other four groups, the protein expressions of CD31、BMP-7、p-Smad1/5/8 were decreased(P<0.05). Compared with HH group, the above changes in YH、YM、YL groups were all improved (P<0.05).
Conclusions: YWHHF can inhibit EndoMT to alleviate pulmonary hypertension, and the mechanism may be related to the promotion of the expression of BMP-7/Smads pathway.
Keywords: BMP-7/Smads signaling pathway; EndoMT; hypoxia and hypercapnia; pulmonary hypertension; rats.