Experimental study of human embryonic stem cell exosomes in the treatment of high-altitude pulmonary hypertension by alleviating pulmonary vascular adventitial fibrosis in mice

Sun Jiashu; Zhao Qixu; Deng Yusong; Xiao Fei; Lyu Lizhi; Zhang Han; Wang Sheng; Wang Qiang; Li Gang

doi:10.3760/j.issn.1673-4777.2025.06.005

Abstract：Objective To investigate the mechanism of high-altitude pulmonary hypertension(HAPH)and the intervention effect of human embryonic stem cell exosomes(hESC-exo)on HAPH.Methods Thirty 8-week-old C57BL/6 male mice were randomly divided into three groups:control group,hypobaric hypoxia group(HH group),hypobaric hypoxia hESC-exo intervention group(HH-exo group),with 10 mice in each group.The mice in the control group were fed in the normobaric and normoxic environment for 35 d.The mice in HH and HH-exo groups were exposed to hypobaric hypoxia for 28 d and then exposed to normobaric and normoxic environment for another 7 d.On day 29,30 and 31 of the experiment,the HH-exo group was injected with 20 μg hESC-exo via the tail vein,and the control group and the hypobaric hypoxia group were injected with the same volume of phosphate buffer solution.Right ventricular systolic pressure(RVSP),right ventricular hypertrophy index(RVHI)and pulmonary arterial wall thickness(PA thickness)were evaluated on day 35.The mRNA and protein expression levels of α-smooth muscle actin(α-SMA),α-1 collagen(Col1-a1)and fibronectin(FN)were detected by real-time fluorescent quantitative polymerase chain reaction and Western blotting.Results After successful modeling,RVSP,RVHI and PA thickness in HH group were significantly higher/larger than those in control group(all P＜0.05).Four days after the last exosome injection,the pulmonary vascular resistance and pulmonary vascular morphology of mice in each group were re-evaluated.The results showed that the RVSP,RVHI and PA thickness of the HH-exo group were significantly lower/smaller than those of the HH group[(21.0±3.8)mmHg vs(26.8±3.6)mmHg,(0.256±0.016)vs(0.361±0.018),(0.54±0.11)vs(0.79±0.13)](all P＜0.05).The mRNA and protein expression levels of α-SMA,Col1-a1,and FN in the HH-exo group were signifi-cantly lower than those in the HH group(all P＜0.05).Conclusions Pulmonary adventitial fibrosis is the main histopathological feature of hypoxia-induced pulmonary hypertension in mice.hESC-exo can effectively alleviate HAPH induced by hypobaric hypoxia in mice by reducing pulmonary adventitial fibrosis.