RESUMO
A segment of autologous sciatic nerve was transplanted into the 17/18a borderoregion or near the midline of the occipital brain in the adult golden hamsters.After42-131 days survival time,HRP (50% in saline) was administered to the cut endof the graft.It was found that the neurons of different sizes and shapes in visualcortex can be induced to regenerate their fibers into the peripheral nerve graft forup to 10mm;Some of the regenerated cells became larger than that of the normal cells.in the visual cortex,which is similar to that in the retina,but the ability of regenera-tion of the cortical neurons is much lower than that of the retinal ganglion cells.Fluorescent dye double-labelling method was used and it was demonstrated thatthe callosal neurons in visual cortex can regenerate their fibers into peripheral nervegraft,the regenerative fibers originated from axotomized neurons rather than fromcollateral sprouting of undamaged neurons.Predegeneration treatment for the sciaticnerve did not enhance the regeneration of neurons in the visual cortex.Extradamagemade near the graft insertion does not seem to increase the quantity of regenerationcells in the visual cortex.The results of the experiment suggest that peripheral nerve graft can induceregeneration of neurons in visual cortex and the local environment is one of theimportant factors affecting the ability of regeneration of mammalian CNS.
RESUMO
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.\;