2.2 Cell grouping and the hyperoxia model
This experiment included four groups. The control group featured primary HUVECs in ECM medium which were cultured at 37℃ in a 5% CO2 incubator. The Normoxia+Harmine group featured primary HUVECs cultured in ECM medium containing harmine (at a final concentration of 3μmol/L) under the same conditions as the control group. In the Hyperoxia group, primary HUVECs were added to ECM medium; then we applied the hyperoxia modeling method described in our previous study 23. The cells were treated with a high-purity gas mixture containing 950 ml/L O2 and 50 ml/L CO2 at a rate of 3 L/min for 10 min. The oxygen concentration was measured dynamically with a ML-IICB digital intelligent oxygen system and maintained above 90%. The cells were treated with high levels of oxygen once every 24 hours, and then cultured under the same conditions as the control group. In the Hyperoxia+Harmine group, the primary HUVECs were cultured in ECM medium containing harmine at a final concentration of 3μmol/L under the same conditions as the hyperoxia group. The next steps of the experiment were carried out after the cells in the four groups had been cultured for 48 hours.