BACKGROUND: Diabetic retinopathy (DR) is a leading cause of acquired blindness in adults. Previous research has shown that the apoptosis of retinal ganglion cells(RGCs) plays an important role in the initiation and development of diabetic retinopathy. The positive effect of estrogen on the nervous system is currently attracting increasing attention. In this study, we investigated whether17β-estradiolum (E2) has protective effects on RGCs in a high-glucose environment. METHODS: The cell survival rates were measured by Cell Counting Kit-8, the apoptosis was detected by flow cytometry, the intracellular reactive oxygen species (ROS) levels were examined by immunofluorescence method, and the intracellular mitochondrial membrane potential was examined by confocal microscopy. The expression levels of cytochrome C, Bcl-2, and Bax were analyzed by Western blot method. The effect of estrogen receptor blocker tamoxifen on the RGCs was also evaluated. RESULTS: It was found that E2 stabilizes the mitochondrial membrane potential, reduces intracellular ROS levels, up-regulates Bcl-2 expression, inhibits Bax expression, decreases the generation of cytochrome C, and finally reduces the apoptosis of RGC-5 cells in a high-glucose environment. These protective functions could be attributed to E2 receptors, which make E2 a prospective patent application candidate in the treatment of DR. Furthermore, when cells were pre-cultured with tamoxifen, we found that tamoxifen inhibited the shielding effects of E2. CONCLUSION: E2 has a broad application prospect in the treatment of DR.