Gypenosides might have neuroprotective and immunomodulatory effects on optic neuritis

Optic neuritis is a common disease in young adults, inducing apoptosis of retinal ganglion cells, which leads to varying degree of visual function damages, even blindness. As the standard treatment, methylprednisolone pulse therapy can only promote the recovery of visual acuity but not prevent retinal ganglion cell degeneration. It cannot help improve the ultimate visual outcome. Both inflammatory response and endogenous oxidative stress play crucial roles in the progression of optic neuritis. The combination of immunomodulatory and antioxidant is expected to improve the prognosis of the disease by preventing the apoptosis of retinal ganglion cells. Triterpenoids (oleanolic acid derived) were reported to have the dual capacity of simultaneously repressing production of pro-inflammatory mediators and exerting neuroprotective effects through induction of anti-oxidant genes in experimental optic neuritis. Gypenosides with an aglycone mainly of dammarane-type tetracyclic triterpenoids, also has the dual capacity of immune regulation and antioxidation. Both gypenosides and oleanolic acid were reported to have similar roles in hepatoprotection. Beside, gypenosides were reported to have the capacity of modulating the activation of immune cells and the expression of cytokines. In addition, gypenosides showed neuroprotective effect against oxidative injury in dopaminergic neurons and mouse model of Parkinson's disease. Accordingly, we propose that gypenosides have potential neuroprotective and immunomodulatory effects on optic neuritis through antioxidation and immune regulation. The application of gypenosides might prevent the apoptosis of retinal ganglion cells and improve the ultimate visual outcome in patients with optic neuritis.