The protective effect of Ginkgo biloba extract on retinal ganglion cells after optic nerve crush in rats

Objective To study the protective effect of Ginkgo biloba extract EGb761 on retinal ganglion cells after optic nerve crush in rat. Methods Forty Wistar rats were divided into experimental and control groups at random. The optic nerves crushed model were made. After 1 h, EGb761 0.05 ml (60 mg/kg ) was injected into the retrobulbar area of injury eyes in experimental group. Balanced salt solution 0.05 ml was injected in control group. The rats in the two groups received injection every other day. On the 3, 7 and 14 d after injury, the eyeballs were enucleated for observing the changes of the retina and RGCs apoptosis.The expression of Bcl-2 and Bax protein were measured with immunohistochemical technique. Results The apoptosis of RGCs in experimental and control groups were seen under microscope. With the extension of injury course, positive cells of apoptosis were increased gradually. The numbers of apoptosis cells in the experimental group were lower than that in the control group, and there were statistically significant difference (P<0.01). The expression of bcl-2 protein in experimental group was significantly higher than that in the control group. The expression of Bax protein and the ratio of Bax/Bcl-2 in the experimental group were lower than that in the control group (P<0.05). Conclusion Ginkgo biloba extract can reduce apoptosis of retinal ganglion cells after rats optic nerve crush, showing obvious protective effect on retinal ganglion cells. The mechanism may be related to the expression of apoptosis gene Bax and Bcl-2. Key words: Retinal ganglion cells; Apoptosis; Ginkgo biloba extract