Effects Of Hypoxia On The Expression Of Angiotensin-converting Enzyme 2 In Human Umbilical Vein Endothelial Cells

Objectives:â‘ To study the influence of the hypoxia on the expression of angiotensinconverting enzyme 2 in human umbilical vein endothelial cells.â‘¡To primarily probe into the mechanism of how the hypoxia works.Methods: HUVECs was cultured as adherent cells. Factorâ…¦was identified by immunohistochemical assay. HUVECs was cultured in 37℃incubators under hypoxia condition (1%O₂+94%N₂+5%CO2) or regular 5%CO2 condition for 3h, 6h, 12h, 24h, respectively. The cell and culture medium were collected respectively. ACE2 protein was measure by immunohistochemical assay statistics analysis was done by SPSS 11.0 software. ACE2 mRNA was quantified by real-time PCR, statistics analysis was done by REST software.Results: â‘ ACE 2 protein expression decreased after hypoxia treatment for 3h, 6h, 12h, and 24 hour compared with regular oxygen condition (χ²=825.078,768.141,623.931,350.260,P＜0.00625). The maximum reduction came at 3h after hypoxia exposure, then raised gradually after 6h, 12h, and 24h exposure;â‘¡ACE2 mRNA expression show a similar tendency to ACE 2 protein. After hypoxia disposal, its relative expression rate reduced to 0.281 at 3h(P=0.031), then increased gradually at 6 hour (0.445, P=0.034), 12h (0.794, P=0.434), 24h(0.891, P=0.692)Conclusion: Our study show hypoxia down-regulate the protein and gene expression of ACE2 in HUVECs in 24 hours. The effect of hypoxia reached maximum level at 3h, and then attenuated gradually at 6h, 12h and 24h, which might indicate that ACE2 may play an important role in regulate RAS in HUVECs after hypoxia injury.