Cytotoxic effect of interleukin-8 in retinal ganglion cells and its possible mechanisms

AIM: To investigate the effect of interleukin-8 (IL-8) on neural retinal ganglion cells (RGCs) and whether it can be alleviated by G31P. METHODS: RGC-5 cells were exposed to IL-8 with or without its specific receptor antagonist G31P for 24h, and the cell viability was assessed by Cell Counting Kit 8 (CCK-8). Apoptosis was measured by examining nuclear morphology and quantifying with flow cytometry. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot were used to investigate the expression of apoptosis-related genes. RESULTS: CCK-8 assay showed that IL-8 significantly inhibits the viability of RGC-5 cells in a dose-dependent manner. Cell apoptosis assays exhibited higher apoptotic rate in IL-8 treatment group compared to control group. We further found that IL-8 could promote Bax and caspase-3 expressions, but decrease the level of Bcl-2 in the aspect of mRNA and protein. However, pre-treatment with G31P partly attenuated these effects in RGC-5 cells (P<0.05). CONCLUSION: These results indicate that anti-proliferation effects of IL-8 through induction of cell apoptosis regulated by Bcl-2, Bax and caspase-3 expressions, can be ameliorated by G31P.