[Effect of Ginkgo biloba extract on the electrophysiology of the isolated retina from a diabetic rat].

The purposes of the experimental work presented here were to ascertain that diabetes causes impairment of the visual function and to test the protective properties of Ginkgo biloba extract against this impairment. The experimental method selected was the isolated albino rat retina maintained in survival by perfusion. Retinal function was evaluated by electroretinographic recording in response to a light stimulus. The rats were made diabetics by injection of alloxan. After one month of diabetes the electroretinogram amplitude was significantly decreased in diabetic rats as compared with control animals. This decrease in amplitude was more pronounced after 2 months of diabetes, which confirmed that retinal function was worse. In rats treated with Ginkgo biloba extract, after 2 months of diabetes the electroretinograms had a significantly greater amplitude that that observed in untreated rats. These results are attributed to the specific role played by free oxygenated radicals on the retina of diabetic rats and to the free radical scavenger property of Ginkgo biloba extract.