Gynostemma Glycosides Protect Retinal Ganglion Cells in Rats with Chronic High Intraocular Pressure by Regulating the STAT3/JAK2 Signaling Pathway and Inhibiting Astrocyte and Microglia Activation

OBJECTIVE: To observe the protective effect of gynostemma glycosides on retinal ganglion cells in rats with chronically high intraocular pressure. MATERIALS AND METHODS: A total of 60 rats were randomly divided into group A (the blank group, 10 rats) and chronic high IOP model group (50 rats). The IOP model group (IOP above 22 mmHg) was then randomly divided into an additional 5 groups (10 rats per group): group B (negative control group) treated with normal saline; group C treated with gynostemma glycosides 25 mg/(kg-d); group D treated with gynostemma glycosides 50 mg/(kg-d); group E treated with gynostemma glycosides 100 mg/(kg-d); and group F (positive control group) treated with VitB1 and VitB12. The eyes of each rat were monitored from day 1 to 14 (D1–D14). On day 14, rats were euthanized, after which retinal tissue and optic nerve were examined using real-time PCR, western blot, HE staining, LFB staining, and TUNEL assay. RESULTS: Groups A, C, D, E, and F had significantly lower expression of CD11b, GFAP, Brn3α, and more TUNEL cells than in group B (all P < 0.05). Moreover, the relative expression of STAT3 mRNA and JAK2 (mRNA and protein) in groups A, C, D, E, and F was significantly lower than in group B (P < 0.05), while in group E, the expression was lower than in group D (P < 0.05). CONCLUSION: Gynostemma glycosides protect retinal ganglion cells in rats with chronically high intraocular pressure possibly associated with the STAT3/JAK2 signaling pathway.