Protection Of BYHWD On Neurons After Rat Rubrospinal Tract Transection

PARTⅠEstablishment of the rubrospinal tract transection animal modelObjective To provide a simple and reliable animal model of rubrospinal tract(RST) transection.Methods Adult SD rats were divided into model group and sham operation group.According to the natural anatomical characters of rat spinal cord,cervical curves of the rats were changed from inferior to superior,rats received yellow ligment and a right-sided lateral funiculus transection or yellow ligment transection at the level between the 3^rd and 4^th cervical spinal cord(C3 and C4) under the operating microscope. Fast-Blue(FB) retrograde tracing of RST,Nissl staining of the spinal injured site and behavior analysis were carried out to evaluate the effect of RST transection.Results There was no FB labeled rubrospinal neuron in the model group,whereas FB labeled neurons were detected in the sham operation group;It was showed by Nissl staining that in the model group the right lateral funiculus and small part of gray matter were disconnected after transection,while the right posterial funiculus and the left half of the spinal cord remained intact;The injured forelimb was not used during spontaneous vertical exploration in the model group,whereas normal used in the sham operation group.Conclusion These results indicate that RST could be completely transected between C3 and C4 without damaging the vertebral lamina.It is not only simple but also practicable and reliable for the RST transection model made in this method.The RST transection model is good for the study of spinal cord injury. PARTⅡEffect of BYHWD on survival,regeneration and functional recovery of neurons after rubrospinai tract transectionObjective To explore the effect of BYHWD on survival, regeneration and functional recovery of neurons after rubrospinal tract transection.Methods Adult SD rats were divided into experimental group, control group and normal control group.Rats received treatment of either BYHWD or DW via gastrogavage after a right lateral funiculus transection at the level between C3 and C4 in the experimental or control group.Location of rubrospinal neurons in the RN was determined by Flouro-gold(FG) retrograde tracing.Eight weeks after injury,viability and atrophy of RN neurons were determined by Nissl staining,axon regeneration was examined by biotinylated dextran amine(BDA) tracing techniques,and functional recovery was studied by a test of forelimb usage during spontaneous vertical exploration.Results The FG labeled RN was 1200μm long,located ventrolateral to the aquaeductus cerebra at the superior colliculus level.RN cell number and mean somal size were decreased 22%and 35% in the experimental group and 42%and 64%in the control group respectively.There was a small number of BDA-labeled axons in the caudal of injury site in the experimental group,whereas no caudal axonal regeneration was detected in the control group.Rats in the experimental group used the injured forelimbs more often than those in the control group.Conclusion These results indicate that administration of BYHWD following RST transection leads to enhancement of axotomized neuron survival,prevention of neuronal atrophy,promotion of transected axon regeneration and functional recovery. PARTⅢEffect of BYHWD on expression of BDNF and cAMP of neurons in red nucleus after rubrospinal tract transectionObjective To explore the effects of BYHWD on expression of BDNF and cAMP of RN neurons after RST transection.Methods Adult SD rats were divided into experimental group, control group and normal control group.Rats received treatment of either BYHWD or DW via gastrogavage after a right lateral funiculus transection at the level between C3 and C4 in the experimental or control group.After survival for 3,7,14 or 21 days,animals were sacrificed. Immunohistochemistry and radioimmunoassay were employed for detection of BDNF expression and cAMP concentration in RN neurons after RST transection.Results Showed by BDNF positive cell count and average gray value of BDNF positive products,BDNF expression was up-regulated both in the experimental and control group at the 3^rd and 7^th day after injury.Whereafter,BDNF expression in the control group was reduced, while in the experimental group,it remained the high level as the 7^th day's. It was found by cAMP radioimmunoassay that cAMP concentration was decreased both in the experimental and control group at the 3^rd day after injury.And it was then increased from the 7^th day and remained a high level until to the 21^st day in the experimental group(compared with normal control,P＜0.05),whereas decreased in the control group (compared with normal control,P＜0.05).Conclusion These results indicate that administration of BYHWD following RST transection leads to Up-regulation of BDNF and cAMP expression in red nucleus.