Abstract
Abstract: :
Purpose: To investigate the neuroprotective effects of ginkgo biloba extract (EGb761) on retinal ganglion cells in optic nerve crush model in rats. Methods: Ninety SD rats were randomly divided into five groups, negative control group, positive control group, low dose treatment group, middle dose treatment group and high dose treatment group with 18 in each. The right eyes of all rats were crushed by a micro–clip with 40g power for 60 seconds 2 mm from the eyeball. The left eyes were not crushed. The negative control, positive control, low dose, middle dose and high dose group were given normal saline, 1% Erigeron Breviscapus, 0.25% EGb 761, 1% EGb 761 and 4% EGb 761 5ml/kg respectively two hour after optic nerve crush and then everyday by feeding. The experiment has lasted for 4 weeks. Retinal ganglion cells (RGCs) were retrograde labeled by injecting 3% fluorogold into both side of superior colliculus 5 days before the sacrifice of the rats. Four photographs were taken from every quadrant 2mm from the center of optic disc. RGCs were quantitatively analyzed by computer with CPAS software. The survival percentage of RGCs equals RGCs density in right eye divided by that in left eye and multiply by 100%. Results: The average survival percentage of RGCs were 60.59%, 73.80%, 66.49%, 71.60% and 74.17% in negative control, positive control, low dose, middle dose and high dose group. Significant difference was found between negative control and any other group (p<0.05 all). There was significant different between low dose and middle dose (p=0.038) , low dose and high dose group ( p=0.003). No significant difference was found between middle dose and high dose group (p=0.33), but the survival percentage was increased by 2.57%. No significant different was found between positive control and middle dose treatment group. Conclusions:EGb761 has neuroprotective effects on RGCs in optic nerve crush model in rat and a dose dependent relationship was found in EGb 761. It was also found that Erigeron Breviscapus has neuroprotective effects on RGCs.
Keywords: neuroprotection • ganglion cells • microscopy: light/fluorescence/immunohistochemistry