In this study, South Korean researchers investigated the neuroprotective effects of Ginkgo biloba extract (GBE) against hypoxic injury to retinal ganglion cells (RGC) both in vitro and in vivo. Their findings were published in the Journal of Medicinal Food.
Hypoxia-induced oxidative stress and disturbed microvascular circulation are both implicated in the pathogenesis of glaucoma.
On the other hand, GBE has been shown to protect against oxidative stress and impaired vascular circulation.
For their in vitro experiment, the researchers first induced oxidative stress in RGC using hydrogen peroxide (H2O2).
They then treated the cells with a vehicle (control) or EGb 761, a standardized GBE.
For their in vivo experiment, the researchers induced hypoxic optic nerve injury by clamping the optic nerve of rats with a microserrefine clip, which was applied without crushing the optic nerve.
They administered EGb 761 (at different concentrations) or the vehicle intraperitoneally and measured RGC density to estimate cell survival both in vitro and in vivo.
The researchers reported that the survival of RGC in vitro was significantly higher upon treatment with 1 or 5 mcg/mL EGb 761.
In vivo, RGC density upon treatment with 100 mg/kg body weight and 250 mg/kg body weight EGb 761 was also significantly higher than the density measured after treatment with the vehicle.
Based on these findings, the researchers concluded that Ginkgo biloba extract has neuroprotective effects against hypoxic injury.
Cho HK, Kim S, Lee EJ, Kee C. NEUROPROTECTIVE EFFECT OF GINKGO BILOBA EXTRACT AGAINST HYPOXIC RETINAL GANGLION CELL DEGENERATION IN VITRO AND IN VIVO. Journal of Medicinal Food. 06 August 2019;22(8):771–778. DOI: 10.1089/jmf.2018.4350