ABSTRACT
Objective\ The present study was carried out to examine the relationship between the distance of axotomy and axonal regeneration systematically,and the effect of a pre\|degenerated peripheral nerve(PN) graft on axonal regeneration of retinal ganglion cells(RGCs) axotomized at different distances. Methods\ The optic nerve(ON) was transected at 0^5,1,1^5,2,3 or 7mm from the optic disc and a normal (the normal group) or pre\|degenerated(the pre\|degeneration group) PN graft was transplanted onto the ocular ON stump in adult hamsters. Results\ In both groups,the number of regenerating RGCs 28 days after grafting decreased significantly when the distance of axotomy increased from 0^5 to 7mm with a sharp decline between 0^5 and 3mm.When the corresponding distance points between the two groups were compared,enhanced regeneration was observed at 2 and 3mm in the pre\|degeneration group. Conclusion\ These results show that the distance of axotomy on the ON of adult hamsters is critical in determining the number of regenerating RGCs.The beneficial effect of a pre\|degenerated PN graft on axonal regeneration of axotomized RGCs is conditional on the distance of axotomy.\;