ISSN: 2577-4360
Authors: Cong-Cong Z, Sai Z, Zheng-Yang S, Dan-Na H, Yong-Yue D and Wan-tie W*
Objective: To investigate the effect of astragaloside on alleviating hypoxia-hypercarbia pulmonary hypertension by inhibiting endothelial-mesenchymal transition (EndoMT) via BMP-7/Smads pathway. Methods: Cell part: Rat pulmonary artery endothelial cells (RPAECs) were divided into normoxic control(C) group, hypoxia-hypercapnia(HH) group and BMP receptor agonist rhBMP-7(HB) group. Group C was cultured in a normal oxygen incubator, and the remaining 2 groups were cultured in a low oxygen and high carbon dioxide incubator. The expression levels of CD31 and α-SMA were observed by immunofluorescence staining. The mRNA and protein expression levels of α-SMA, CD31 and Smad1/5/8 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Cell proliferation level was detected by CCK-8 assay. Cell migration level was detected by Transwell chamber assay. Animal part: forty male healthy SD rats of clean grede, weighting (180~220) g, were randomly divided into 4 groups (n=10): normoxia group (N), hypoxia-hypercarbia group (HH); astragaloside high dose group (AH) and low dose group (AL). N group was kept in normoxic environment, the remaining three groups were intermittently exposed to hypoxia-hypercarbia environment (9%ï¾11% O2, 5%ï¾6% CO2) for 4 weeks, 6 days a week, 8 hours per day. The rats in AH and AL groups were received astragaloside gavage in a dosage of 2,4mg/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. Results: Cell part: Compared with the C group, α-SMA mRNA and protein expression levels were increased in HH group (P<0.01), while CD31 mRNA and protein expression levels, Smad1/5/8 mRNA and P-Smad1/5/8 protein expression levels were decreased (P<0.01), cell proliferation decreased and migration increased (P<0.01). Compared with HH group, the expression of α-SMA mRNA and protein in HB group decreased (P<0.01), while the expression levels of CD31 mRNA and protein, Smad1/5/8 mRNA and P-Smad1/5/8 protein increased (P<0.05, P<0.01), proliferation increased and migration decreased (P<0.05, P<0.01). Animal part: Compared with the N group, the mean pulmonary artery pressure and right ventricular hypertrophy index increased in the other three groups. Compared with HH group, the above changes were alleviated in the Chinese medicine group (P<0.05). Conclusion: hypoxia and hypercapnia can promote EndoMT in RPAECs, thereby promoting the development of HHPH, and its mechanism may be related to inhibition of BMP-7/Smads pathway.
Keywords: Hypoxia and hypercapnia; BMP-7/Smads signaling pathway; EndoMT; Pulmonary hypertension; Rats; Pulmonary artery endothelial cells
