In OIR, mouse pups (C57BL/6J, male and female) were orally gavaged with creatine monohydrate (500 mg/kg; C3630; Sigma-Aldrich, St Louis, MO, USA) or PBS (control; 10010–023; Thermo Fisher Scientific) daily, from P12 to P16. Five mice each were allocated to the creatine treatment group and to the vehicle group. At P17, eyes were enucleated and retinas were stained with Alexa Fluor 594-conjugated isolectin GS-IB4 (10 μg/ml; I21413; Thermo Fisher Scientific), as described [24 (link)]. Then, retinas were visualised using anF epifluorescence microscope (AxioObserver.Z1; Carl Zeiss Microscopy, Jena, Germany). Mice weighing less than 5.0 g were excluded from this study [25 (link)]. At P17, the areas of retinal NV and vaso-obliteration (VO) were quantified as previously described [26 (link)].