Experimental Study Of End-to-Side Neurorraphy Of Peripheral Nerves In Rats

ln this study the peroneaI nerves of adult rats were sectioned and theirdistal ends were sutured to the lateraI side of the tibial nerve trank with removaIof the epineurial sheath. Recovery of morphology and function affer end-to-side neurorrhaphy was observed to study the potentiality of lateraI sprouting.The molecuIar mechanisms of nerve Iateral sprouting and effect ofexogeneous NGF by local injection affer end-to-side neurorrhaphy werestudied.The HE staining, electron microscopic examination, eIetrophysiologicaltest and HRP retrograde tracing were carried out to observe the regenerationof sensory and motor fibers of injured neurons and the dfferentiate of them.lmmunohistochemical analysis by the computer image analysis was performedto study the expression of the NGF CNTF and S-100 affer end-to--sideneurorrhaphy. Expression of GAP-43 and increased ChAT were investigatedwith immunochemistry techniques. Choline acetyItransferase activity to studythe regulation of exogeneous NGF and survival of injuried neurons wasobserved with HRP retrograde tracing to study the effect of exogeneous NGFMain results and conclusions are as followst:1. Regeneration axons of donor nerve could growing into the distal end ofinjuried nerves by Iateral spouting. Function and morphology of donor nerveswere normal show that the end-to-side neurorrhaphy did not impair to thedonor nerve.2. The labelled neurons were found in the anterior horn of the spinal cord andthe spinal ganglia show that the regeneration axons had motor fibers as wellas sensory fibers. The motor nbers and the sensory fibers derived from thex=.kx, M~ .t*tatetrelevant seCtions Of spinal coFd and spinal ganglia of sciatic nerve. Theregeneration Of sensory fibers was superior to that Of motor fibers comparingwith end4orend neurorrhaphy.3. Increased expression Of NGF were observed in diStaI ends aff6r end4o-sidneurorrhaphy, and downregulation Of CNTF in distal ends and thenupreguIation was aIso observed. Tt show that the neurotrophic f9otOrs may beaCts as an important roIe in IateraI sprouting. The down-reguIation Of S-100may promot6 Schwann ceIls prolif6ration and migation, and imply thatSchwann celIs was an important role in lateral sprouting.4. Exgeneous NGF can prot6Ct the injured neurons while primary repair WeaIso find that NGF can improve the survivaI of motor neurons, and upregulationOf GAP43 and ChAT by NGF which aCts as a reguIation faCtor to promOtenerve regeneration were obseved.5. The molecular mechanisms of lat6ral sprouting are stilf obscure. Furtherresearch is expeCted, but it provide anOther option fOr surgical treaboent ofnerve repair The results of end4o-side neurorrhaphy was not as good as thatof end4o-end neurorrhaphy. We suggeSt that end4o-end is best whenproximal ends are available.