| Objectives:To investigate the expression of Nogo-A protein in acute spinal cord injury rats treated with granulocyte colony-stimulating factor(G-CSF).Methods:In this experiment,A self-made Allen's hammer was used to make a model of acute spinal cord injury on the ninth thoracic of rats.,Forty-eight SD rats were divided into three groups: the simple laminectomy group(the normal,n=16),the acute spinal cord injury(control groups,n=16)and the G-CSF treated after injury(treatment group,n=16),A spinal cord injury model was made using Allen's batcher,The segments of T8 to T10 were injured,G-CSF subcutaneous injection was administered early in the treatment group,Normal group and control group were given the same dose of normal saline injection at the same time point.Three groups were performed BBB grading on the hind limbs on days 1,3,7 and 14 after surgery,.The rats were then sacrificed and were put into the heart intubation paraformaldehyde perfusion for fixation.The damaged segmental spinal cord were taken for HE staining for the observation of the morphological changes of the spinal cord tissue at each point,Immunohistochemical staining was used to detect the dynamic expressions of Nogo-A protein at each time point in the damaged spinal cord tissues,and the relative expression of Nogo-A protein in the spinal tissue was measured by using the high resolution histopathological management system.The Western-blot was used to determine the expression of Nogo-A protein in each group,and compared with the normal group.Results:1.BBB score Both the treatment group and the control group showed delayed paralysis after operation.There was no significant improvement in the motor function of the hind limbs of the two groups in the first 3 days.The function of the hind limb of the injured group was gradually restored on days 7 and 14,the BBB score of the treatment group was significantly higher than that of the control group on days 7d and 14(p<0.05).2.H-E staining Microscopically,the spinal cord tissues in the treatment group and the control group had structural disorder after the injury,It is characterized by edema,hemorrhage and inflammatory cell infiltration.As time goes on,the neuron fibers in the spinal cord became necrotic and fracture,and vacuolar degeneration was present,ans eventually developed into resulting in collagen scarring.However,in the G-CSF treatment group,the nerve fibers were arranged in an orderly way,with little hyperplasia of microglia,and there were more focal bleeding and residual neurons was more than in the control group,which was basically normal structure.3.Immunohistochemical staining Nogo-A protein was expressed in all three groups.The expressions of Nogo-A protein of post-injury at each time points in both treatment and control groups were apparently higher than these of the normal group(p<0.05).The Nogo-A protein expression peaked at day 7 in both control and G-CSF groups after the injury,then gradually decreased,and the expression intensity showed the characteristics of day 7>day 14>day 3>day 1.At each time point,the expression of Nogo-A protein in the spinal cord tissues of the treatment group was significantly lower than that in the control group(p<0.05).4.Western-blot The expression of Nogo-A protein in spinal cord tissues was constant after injury.The expression of Nogo-A protein in the spinal tissues of the treatment group and control group was obviously fluctuated.After the injury,the expression of Nogo-A protein reached its peak on day 7,then gradually decreases,its expression intensity presents the characteristics of the fall-rise pattern.The expression of Nogo-A protein was significantly lower in the spinal cord tissues of rats in the G-CSF treatment group than in the control group on the first day,day 3,day 7,and 14 days after surgery.Conclusions:1.The Nogo-A protein increased significantly after acute spinal cord injury in rats,and its expression intensity was characterized day 7> day 14> day 3> day 1.2.The application of granulocyte colony stimulating factor(G-CSF)in the treatment of ASCI rat model may inhibit the expression of Nogo-A protein in injured spinal cord tissues. |
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