Author/Editor		Bajrović, Fajko; Remškar, Mojca; Sketelj, Janez
Title		Prior collateral sprouting enhances elongation rate of sensory axons regenerating through acellular distal segment of a crushed peripheral nerve
Type		članek
Source		J Peripher Nerv Syst
Vol. and No.		Letnik 4, št. 1
Publication year		1999
Volume		str. 5-12
Language		eng
Abstract		Regenerating axons in crushed peripheral nerves grow through their distal nerve segments even in the absence ot Schwann cell support, but their elongation rate is reduced by 30%. We examined whether prior exposure of sensory neurons to trophic factors achicved eilher by collateral sprouting or regeneration after conditioning Iesion could enhance subsequent regeneralion of their axons after crush, and compensate for loss of cell support. Collaleral sprouting of the peroneal cutaneous sensory axons in the rat was evoked by transection of adjacent peripheral nerves in the hind leg. The segment of the peroneal nerve distal to the crush was made acellular by repeated freezing. Sensory axon elongation rate during regeneration was measured by the nerve pinch test. Prior axonal sprouting for two weeks increased the elongalion rate of sensory axons through the acellular distal nerve sement back to normal value observed in control crashed nerves. The number of axons in the accllular distal segment at a fixed dislance from the crush site was about 50% greater in sprouting than in control non-sprouting nerves. However, prior sprouting caused no further increase of axon clongation rate in control crushed nerves. Prior collaleral sprouling, therefore, could in some respect compensate for loss of cell support in the distal nerve segment after crush lesion. This suggests that loss of cell-produced trophic factors is probably responsible for slower elongation rate through the accllular distal nerve segment. Surprisingly, prior conditioning lesion caused no enhancement of elongation rate of the sensory axons regenerating in the absence of cell support.
Descriptors		NERVE CRUSH NERVE REGENERATION PERONEAL NERVE SCHWANN CELLS RATS AXONS