Establishment of oxygen-induced retinopathy mouse model

A total of 80 (36 female; 44 male) 7-day-old healthy C57BL/6 neonatal mice (weight, 3±0.3 g) were provided by the Animal Center of Nanjing University (Nanjing, China). All procedures in the study followed the protocols approved by the Animal Care and Use Committees of Nanjing Medical University (Nanjing, China). The mice were maintained in specific-pathogen-free conditions at the Animal Center of Nanjing Medical University. The mice were reared in a clean grade animal room, at 23±2°C and 50±10% humidity. The light did not exceed 350 lux and the light/dark cycle was 12-h. Food, water and bedding were replaced every two days. The oxygen concentration was monitored with an oxygen concentration detector. The mice were randomly divided into the OIR group (n=40) or the control group (n=40). For OIR modeling, 7-day-old mice were maintained in 75% oxygen condition for 5 days, then in normal room air for a further 5 days. Mice in the control group were maintained in normal room air for the duration of the experiment. The present study was approved by the ethics review board of Nanjing Children's Hospital of Nanjing Medical University.