Variations of Neurotrophic Factors and It's Importances in Spinal Cord Injured Rats and Beagle Dogs

ABSTRACT

STUDY DESIGN: Experimental, prospective study OBJECTIVES: To examine the changes in the variable factors after an acute spinal cord injury(SCI) in rats and dogs simultaneously. SUMMARY OF LITERATURE REVIEW No study has examined the variations of several factors in a SCI model in different species. MATERIALS AND METHODS: In rats, a laminectomy was performed at the T10 level and the injured spinal cord was extracted. In Beagle dogs, the laminectomy level was T10 and T11. The motor function was evaluated using a modified Tarlov's scale. A RT2 profiler PCR array was used to examine each factor (inflammatory cytokines, factors-related with apoptosis, neurotrophic factors, factors-related with extraceullar matrix). RESULTS: IL-2, TNF, TNFRSF11B increased with time and showed no statistical difference between two species, but TNFSF13B showed a significant difference. BDNF decreased with time in both species, and GDNF was significantly lower in dogs. NGFbeta, CTNF and its receptors showed no significant changes in the two species. MMP1 increased in both species but MMP7 decreased in rats and increased in dogs with time, and showed a significant difference between species. CONCLUSION: The change in inflammatory cytokines and extracellular matrix correlates with each factor in the combined patterns. Moreover, during the first week after SCI, inflammatory cytokines, apoptosis, neutrophic factors, and extracellular matrix factors may show a partial difference between experimental animals, which means that an animal model can be selected according to the particular experimental plan.