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MicroRNA-124 (miR-124) is abundantly expressed in neurons in the mammalian central nervous system, and plays critical roles in the regulation of gene expression during embryonic neurogenesis and postnatal neural differentiation. However, the expression profile of miR-124 after spinal cord injury and the underlying regulatory mechanisms are not well understood. In the present study, we examined the expression of miR-124 in mouse brain and spinal cord after spinal cord injury using in situ hybridization. Furthermore, the expression of miR-124 was examined with quantitative RT-PCR at 1, 3 and 7 days after spinal cord injury. The miR-124 expression in neurons at the site of injury was evaluated by in situ hybridization combined with NeuN immunohistochemical staining. The miR-124 was mainly expressed in neurons throughout the brain and spinal cord. The expression of miR-124 in neurons significantly decreased within 7 days after spinal cord injury. Some of the neurons in the peri-lesion area were NeuN(+)/miR-124(-). Moreover, the neurons distal to the peri-lesion site were NeuN(+)/miR-124(+). These findings indicate that miR-124 expression in neurons is reduced after spinal cord injury, and may reflect the severity of spinal cord injury.

Aim: To detect and characterize of 6 monoclonal antibodies (mAbs) against different epitopes of rat Nogo-A molecule in immunohistochemistry to decide their applications in futrue. Four mAbs against Nogo66 fragment are named Nogo66-1, Nogo66-2, Nogo66-3 and Nogo66-4. The rest of 2 mAbs against N-termial 570-691aa fragment are named NogoN-1 and NogoN-2., Methods: The immunofluorescence staining was used to detect the reactivity and specificity of those 6 mAbs in spinal tissue sections of rat., Results: All 6 mAbs were double-labelled with commercial rabbit anti-Rat Nogo-A polyclonal antibody (PcAb) in spinal cord sections respecitvely. All 6 mAbs were colocalization with MBP respectively. However Nogo66-3 and NogoN-1 could also be double-staining with GFAP respectively., Conclusion: Nogo66-1, Nogo66-2, Nogo66-4 and NogoN-2 could recognize specifically in Nogo-A protein of tissues in immunohistochemical methods.

Aim: To analysis the role of T lymphocytes in spinal cord regeneration by comparing the recovery of movement and the morphological changes of injury area between BALB/c and DO11.10 transgenic mice., Methods: Producing a crush injury model of spinal cord with special forceps. Analyze the changes of spinal cord injury area with H&E and GFAP, CD11b and lymphocytic immunohistochemical staining. Evaluate the recovery of movement function with Basso-Beattie-Bresnahan (BBB) locomotion testing system at 0, 7, 14 and 21 day post-injury (dpi)., Results: There were thicker and fastened glial scar at 21 dpi in the BALB/c mice but not in DO11.10 mice. The number of macrophages/microglia infiltrated in spinal cord injury area were more in DO11.10 than that in BALB/c mice at 14 dpi. The numbers of T lymphocytes infiltrated in spinal cord injury area were less in DO11.10 than that in BALB/c mice at 21 dpi. In addition, compare to BALB/c mice, the locomotion movement recovery of DO11.10 mice were much more significant within 3 weeks after spinal cord injury by BBB scoring system., Conclusion: The infiltrated autoimmune activation T lymphocytes which specifically react to neural antigens are not beneficial to recovery of movement after spinal cord injury in mice.

The substantia nigra neurons expressing c-RET, a glial cell line-derived neurotrophic factor (GDNF) receptor intracellular tyrosine kinase subunit, were investigated in rats by using a double labeling method which combined retrograde horseradish peroxidase (HRP) labeling after injection into the striatum with immunohistochemistry to c-RET. It was revealed that the distribution of c-RET-immunoreactive neurons and HRP-labeled nigrostriatal neurons overlapped. Numerous double-labeled HRP/c-RET neurons were found in the substantia nigra pars compacta with predominate distribution ipsilateral to the injected striatum. Semiquantitative cell count indicated that a large percentage (97%) of HRP-labeled neurons showed c-RET immunoreactivity. Furthermore, double-labeled HRP/c-RET ones constituted only 61% of total c-RET-immunoreactive neurons in the substantia nigra ipsolateral to the injected striatum. Taken together with previous observations on glial cell line-derived neurotrophic factor in the basal ganglia, this study provides evidence that the c-RET protein may mediate biological activity of GDNF family ligands in most of projecting neurons in the substantia nigra pars compacta where the dopaminergic neurons are numerously distributed. Specially, it suggests that c-RET-mediating signaling cascades may play important roles in neuron-glial interaction that support and sustain nigrostriatal neuronal circuits in the basal ganglia.