Hypoxia-preconditioned hUCMSC-Exos relieve hypoxic pulmonary hy-pertension by inhibiting pulmonary vascular EndMT / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effect of hypoxia-preconditioned human umbilical cord mesenchymal stem cell-derived exosomes(hUCMSC-Exos)on pulmonary vascular endothelial-mesenchymal transition(EndMT)in hypoxic pulmonary hypertension(HPH).METHODS:(1)Primary hUCMSCs were isolated and cultured by tissue adhesion method,and hUCMSC-Exos were extracted by ultrafiltration and identified.(2)Twenty-four SPF male SD rats were ran-domly divided into normoxia(N)group,hypoxia(H)group,hypoxia+normoxic hUCMSC-Exos group and hypoxia+hypoxia-preconditioned hUCMSC-Exos group,with 6 rats in each group.The rats in H group and intervention groups were placed in a cabin that simulated the hypoxic environment at an altitude of 5 000 m,and normoxic hUCMSC-Exos,hypoxia-precon-ditioned hUCMSC-Exos or equivalent volume of PBS were injected through the tail vein on the 3rd,5th,7th,10th and 14th days in hypoxia environment.After 21 d of modeling,the right ventricular systolic pressure(RVSP)and right ven-tricular hypertrophy index(RVHI)of the rats were detected,and the pathological changes of lung tissues were observed by HE staining.(3)After starvation for 12 h,human pulmonary arteriole endothelial cells(HPAECs)were randomly di-vided into normoxic control(N-Con)group,hypoxic model(H-Con)group,hypoxia+normoxic hUCMSC-Exos group and hypoxia+hypoxia-preconditioned hUCMSC-Exos group.The migration ability and tube formation ability of HPAECs were detected by Transwell assay and tube formation experiment.The expression of CD31 and α-smooth muscle actin(α-SMA)in HPAECs was detected by immunofluorescence double-staining.The protein levels of CD31,VE-cadherin,α-SMA and vimentin in pulmonary vessels and HPAECs were assessed by Western blot.RESULTS:(1)The HPH rat model was suc-cessfully established after 21 d of hypoxia,and EndMT occurred in pulmonary vessels.Compared with N group,the levels of RVSP,RVHI,percentage of vascular wall area(WA%)and percentage of vascular wall thickness(WT%)in H group were significantly increased(P＜0.01),pulmonary vascular wall thickening and the protein levels of CD31 and VE-cad-herin were significantly decreased(P＜0.01),while the protein levels of α-SMA and vimentin were significantly increased in pulmonary vessels(P＜0.05 or P＜0.01).Compared with H group,the RVSP,RVHI,WA%and WT%(P＜0.01)were significantly decreased(P＜0.05 or P＜0.01),and pulmonary vascular remodeling was attenuated after normoxic or hypoxia-preconditioned hUCMSC-Exos intervention.After hypoxia-preconditioned hUCMSC-Exos intervention,HPH pul-monary vascular remodeling and EndMT formation were significantly inhibited.(2)After 48 h of hypoxic treatment,the migration,tubule formation and EndMT of HPAECs were induced.Compared with H-Con group,cell migration and tube formation were significantly decreased after hypoxia-preconditioned hUCMSC-Exos intervention(P＜0.01).The protein levels of CD31 and VE-cadherin were increased,while the protein levels of α-SMA and vimentin were decreased(P＜0.05 or P＜0.01).CONCLUSION:Hypoxia-preconditioned hUCMSC-Exos attenuate the formation of HPH pulmonary vascu-lar remodeling by inhibiting pulmonary vascular EndMT.