| Objective: To study the effect and mechanism of venom nerve growth factor on retinal ganglion cells of rats after acute optic nerve injury and To observe the pharmacokinetics of venom neural growth factor(v-NGF)in the vitreous at different time following subconjunctional and intravitreal injection.Method :A Wistar rat model of optic nerve injury was made by using mini-vascular forceps.The rats were divided into control and experimental groups(vNGF100Bu, vNGF50Bu) randomly. After crush injury, 0.025ml vNGF100Bu and vNGF50Bu were injected into the vitreous of injured eyes respectively.The retinal histological changes in retina of different time(2 week,4 week,6 week) after injury were observed.The retinal ganglion cell(RGC) number was counted by using microscope.The changes of bcl-2 mRNA in RGCs were demonstrated by in situ hybridization. Pharmacokinetics: v-NGF was labeled by 131I and was injected into the conjunctival sac and the vitreous cavity of the rabbits,then counts per minutes(CPM)of the vitreous were determined respectively at 1,3,6,12,24,48hour after infection.Results :At 2 week after injury,the RGC numbers of treatment groups were obviously higher than that of the control group.The differences between the treatment and control groups were significant(P<0.01). Furthermore,it was show that there were high expression of bcl-2 mRNA in the treatment groups and no expression in the control group.The result of pharmacokinetics was showed that the concentraction of the drug in vitreous was the hightest at 6hr following subconjunctival injection and at 1hr following intravitreal injection. v-NGF could get higher concentraction in rabbit eyes by intravitreal injection and maintain longer time.Conclusion : vNGF are effective in promoting the repair of injured optic nerve by increasing the survival rate of RGCs,in evoking the expression of bcl-2 mRNA and in promoting the function of the optic nerve. v-NGF can be well distributed in intraccular part following intravitreal injection.
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