GRGM-13 comprising 13 plant and animal products, inhibited oxidative stress induced apoptosis in retinal ganglion cells by inhibiting P2RX7/p38 MAPK signaling pathway

Objective: To determine the effectiveness of GRGM-13 on oxidative stress induced apoptosis of retinal ganglion cells (RGCs) and revealed its possible mechanism. Materials and methods: Caspase-3 activity, MDA level, and glutathione peroxidase level were detected by Caspase-3 assay kit, Lipid Peroxidation MDA Assay Kit, and Total Glutathione Peroxidase Assay Kit, respectively. Protein levels of Bax, Bcl-2, p-p38 and p38 were observed by Western Blot. Reactive oxygen species assay kit was used to determine intracellular ROS level. Apoptotic cells were measured by flow cytometry. Results: GRGM-13 inhibited apoptosis of RGCs and ROS level in rat retinal tissue and RGC-5 cells, and the decrease degree strengthened with the increase of GRGM-13 concentration. In addition, ROS upregulated p-p38 expression, while GRGM-13 reversed this effect. We also found that p38 inhibitor SB202190 did not change Lglutamate (Glu) or H2O2-induced ROS level, while SB202190 inhibited apoptosis of RGC-5 cells. Finally, we observed that P2x7R agonist BzATP reversed the inhibition effect of GRGM-13 on RGC-5 cell apoptosis, ROS level and p-p38 expression, while si-P2x7R inhibited oxidative stress-induced phosphorylation of p38. Conclusion: GRGM-13 could inhibit oxidative stress-induced RGCs apoptosis via inhibiting P2RX7/p38 MAPK pathway, which revealed the possible mechanism of GRGM-13 on stress-induced RGCs apoptosis and provided new Chinese medicine for the treatment of glaucoma.