The Effect Of RhEPO On NTF Expression And Neuronal Apoptosis After Spinal Cord Injury

Erythropoietin(EPO),34kd,is a sialoglycoprotein. EPO was considered to be excreted only by the kidney and responsible for the proliferation,maturation,and differentiation of the precursors of the erythroid cell line incretory hormone. Recent studies have demonstrated that,in addition to kidney,liver,lung,spleen,Placenta and Procreative organ can excrete EPO. EPO and its receptors (EPOR) are widely expressed in the central nervous system(CNS). EPO,a multifunctional nutritional factor and neuroprotective factor,which can modulate the inflammatory and immune response,not only plays a crucial role in the regulation of erythropoiesis,but also plays a crucial role in the regulation neurodevelopment,and have neuroprotective function in different conditions of neuronal damage.The experimental study is to explore the effect about rhEPO on neuromotor function, secondary pathology change and expression of NTF and the apoptosis of neural cell, which administered at different time after traumatic spinal cord injury. The experimental study is devided into three parts:The first part The effect of rhEPO on NT-3 and NGF expression after traumatic spinalcord injuryObjective Nerve growth factor (NGF) and neurotrophic factor–3(NT-3) are chief members in neurotrophic factors family, which can promote nerve cell survival,growth and differentiation. They can prevent nerve cell from death,promote nerve cell and axon recovery and regulate synaptic plasticity. They are important indexs, which reflect spinal cord recovery.This part is to explore the effect about rhEPO on neuromotor function, secondary pathology change and expression of NT-3 and NGF, which administered at different time after rat traumatic spinal cord injury.Method Wistar rats were randomized into normal group, sham operation group, control group and experiment group. SCI model is made according to improved Allen crush model. The Wistar rats in experiment group were peritoneal injected with rhEPO (5000ku/kg) at 1h, 6h and 24h after traumatic spinal cord injury. The injuries of spinal cord were estimated by the score of neurological function and histopathology. The expression of NT-3 and NGF were detected by immunohistochemistry methods.Result 48 hours after traumatic spinal cord injury,neuromotor function and secondary pathology change are significantly improved in rhEPO 1h ,6h group. Compared to concurrent control groups, the angles from improved tiltboard experiment(43.5±3.45; 42±1.98)obviously increased(P<0.05). The indexes of the expression of NT-3 and NGF increased significantly (P<0.01). But in rhEPO 24h group, the increases of the indexes are not statistically significant (P>0.05).Conclusion Early application of rhEPO could lessen the lesion of neuromotor function and secondary pathology change. The protection is partially due to the increase of expression of NT-3 and NGF, protection of nerve cell and promotion of spinal cord.The second part The effect of rhEPO on Caspase-3 expression of neural cell after traumatic spinal cord injuryObjective Cysteine proteinases (Caspase)are consided to be the capital series of protease during apoptosis, while Caspase-3 , the most important one, is the effective part in the co-downstream of many apoptosis pathway. This part is to explore the effect of rhEPO on neuromotor function,secondary pathology change and expression of Caspase-3, which was peritoneal injected at different time after rat traumatic spinal cord injuryMethod Wistar rat were randomized into normal group,sham operation group, blank control group and rhEPO group. SCI model is made according to improved Allen crush model. The injuries of spinal cord were estimated by the score of neurological function and histopathology. The index of neural cell apoptosis and Caspase-3 expression were detected by immunohistochemistry. Result Compared to concurrent control groups,neuromotor function and secondary pathology change are significantly improved in 1h and 6h experiment group. The indexes of neural cell apoptosis and Caspase-3expression decreased significantly (P < 0.01). But in 24h experiment group, the decreases of the indexes are not statistically significant.Conclusion Early application of rhEPO could lessen the lesion of neuromotor function and secondary pathology change. The protection is partially due to the reduction of expression of Caspase-3 and neural cell apoptosis.The third part Protective effect of Erythropoietin on neuronal apoptosis after spinal cord injuryObjective Nerve cell apoptosis is the significant pathologic change in secondary lesion of spinal cord。This part is to explore the Protective effect of rhEPO on neuromotor function and apoptosis of neural cell, which was peritoneal injected at different time after rat traumatic spinal cord injury.Method Wistar rat were randomized into normal group,sham operation group, blank control group and experiment group. SCI model is made according to improved Allen crush model. The injuries of spinal cord were estimated by Tarlov grade and tiltboard test. The indexes of neural cell apoptosis were detected by immunohistochemistry and terminal deoxynucleotide transferase-mediated dUTP-biotin nick end labeling (TUNEL) method.Result Compared to concurrent control groups, neuromotor function are significantly improved in 1h and 6h experiment group. The indexes of neural cell apoptosis decreased significantly (P < 0.01). But in 24h experiment group, the decrease of the index are not statistically significant.Conclusion Early application of rhEPO could lessen the lesion of neuromotor function. The protection is partially due to the reduction of neural cell apoptosis.