VISUAL-EVOKED POTENTIALS AND OPTIC-NERVE HISTOPATHOLOGY IN NORMAL ANDDIABETIC RATS AND EFFECT OF GINKGO-BILOBA EXTRACT

The purpose of this study was to test the possible therapeutic role of a ginkgo biloba extract on the impairment of visual function and path ological histology of the optic nerve caused by early diabetes. Ginkgo biloba extract entraps oxygenated free radicals and is also a strong inhibitor of the platelet activation factor (PAF). For this purpose, V EP recordings and optic nerve histopathology were studied on alloxan d iabetic and normal Swiss albino rats in four experimental groups. The VEP recordings showed no statistical significance between diabetic and normal rats. However, the amplitudes were significantly increased in diabetic animals with ginkgo biloba extract compared with the diabetic s, supposing an impression of axonal protection. But the amplitude val ues were decreased in normal treated with the same extract compared wi th normal animals, assuming a toxic activity. Optic nerve ultrastructu ral findings also confirmed these VEP changes. It was concluded that t his extract could be encouraging for human clinical trials of diabetes .