栀子苷对高糖诱导的视网膜神经节细胞损伤的抑制作用及其机制OA

Objective To explore the inhibitory effect of geniposide on high glucose(HG)-induced damage to retinal ganglion cells(RGCs)and its mechanism.Methods The RGC-5 cells in the logarithmic growth phase were grouped and treated as follows.Control group:Cells were cultured using conventional medium.Cells in the other groups were cultured under the same conditions as those in the control group,but subjected to different treatments.HG group:Cells were treated with 30 mmol·L-1 glucose for 24 hours.HG+cGAS-STING pathway inhibitor group(HG+C176 group):After pretreatment with 5 nmol·L-1 C176 for 24 hours,the cells were cultured in a medium containing 30 mmol·L-1 glucose for another 24 hours.HG+low-concentration,high-concentration geniposide treatment groups(HG+GEN-L group,HG+GEN-H group):After being pre-treated with 64 mmol·L-1 and 256 mmol·L-1 geniposide,respectively,for 24 hours,the cells were further cultured in a medium containing 30 mmol·L-1 glucose for another 24 hours.HG+high-concentration geniposide+cGAS-STING pathway activator group(HG+GEN-H+DMXAA group):After pre-treatment with 256 mmol·L-1 geniposide and 177 mmol·L-1 DMXAA for 24 hours,the cells were further cultured in a medium containing 30 mmol·L-1 glucose for an-other 24 hours.Cell viability was detected using the cell counting kit-8 method.Enzyme-linked immunosorbent assay was performed to detect the levels of tumor necrosis factor-α(TNF-α),interleukin(IL)-1 β,and IL-6 in the cells,as well as the content of malondialdehyde(MDA)and glutathione peroxidase(GSH-Px),and the activity of superoxide dismutase(SOD).The level of reactive oxygen species(ROS)was detected by the DCFH-DA probe.Flow cytometry was used to de-tect cell apoptosis,and Western blot was used to measure the expression levels of PCNA,Ki-67,Bax,Bcl-2,Cleaved Caspase-3,cGAS,and p-STING/STING proteins in the cells.Results HG treatment significantly reduced the activity of RGC-5 cells and downregulated the expression levels of PCNA and Ki-67 proteins(all P＜0.05),while C176(cGAS-STING inhibitor)and geniposide(low-and high-concentration geniposide treatment)interventions reversed the said changes(all P＜0.05).The DMXAA(cGAS-STING agonist)partially counteracted the protective effect of high-concentration geniposide.In terms of inflammatory indicators,HG significantly increased the expression of pro-inflammatory factors like TNF-α,IL-1β,and IL-6(all P＜0.05);C176 and geniposide treatment effectively inhibited their expression(all P＜0.05),while DMXAA reversed this inhibitory effect.The results of the oxidative stress detection showed that in the HG environment,the MDA content and ROS level in RGC-5 cells increased,while the SOD activity and GSH-Px content decreased(all P＜0.05).The C176 and ge-niposide intervention improved the above oxidative stress indicators(all P＜0.05),but this effect was partially counteracted by DMXAA.The apoptosis-related experiments demonstrated that HG caused an increase in the apoptosis rate of RGC-5 cells,the Bax/Bcl-2 ratio,and the expression of Cleaved Caspase-3(all P＜0.05);treatment with C176 and geniposide sig-nificantly inhibited these apoptotic indicators(all P＜0.05),while DMXAA reversed the anti-apoptotic effect of geniposide.HG treatment significantly upregulated the expression of cGAS protein and the p-STING/STING ratio in RGC-5 cells(both P＜0.05).Intervention with the cGAS-STING inhibitor C176 and different concentrations of geniposide could effectively inhibit the activation of this pathway(all P＜0.05),while the agonist DMXAA could partially reverse the inhibitory effect of high-concentration geniposide(P＜0.05).Conclusion Geniposide can inhibit the damage to RGC cells caused by HG,which is related to its inhibitory effect on the activation of the cGAS-STING pathway.