The Differentiation of Phase of Spinal Cord Injury Based on the Changes in Gene Expression

ABSTRACT

STUDY DESIGN: An experimental study. OBJECTIVES: To define the phases of chronic spinal cord injury by researching the changes in gene expression. SUMMARY OF LITERATURE REVIEW The exact time of conversion from acute stage to chronic stage in spinal cord injury is unknown. MATERIALS AND METHODS: We used 18 month-old Beagle dogs as study subjects. Under spinal cord monitoring, we underwent laminectomy on thoracic vertebra 10 and 11, and induced cord injury by a weight-drop injury method. Dogs in each group with spinal cord injury and group without spinal cord injury on POD 1, 7, 30, and 90. The motor functions were evaluated using the Tarlov scale. Tissues were prepared from 0.5cm up and down from the 10th thoracic level. Additional cephalic and caudal lesions from the injured site were prepared. We have checked the differentially expressed gene(DEG). RESULTS: The mean Tarlov value was 0.67 which indicated a significant cord injury. 4 DEG (GP3, 9, 25, 34) were detected among 40 primers after screening, the detection percentage of which was 10. In the tissues of study subjects with spinal injury, DEG was found at the injury site and cephalic lesion. DEG expressed GP3, GP9 and GP34 started expression on day 30, and GP25 was expressed on day 90. CONCLUSIONS: According to the changes in gene expression, the day 30 would be considered as the date of conversion from acute to chronic phase of cord injury. Inhibiting secondary inflammatory change and apoptosis following spinal cord injury until this period would maximize the effect of chronic phase therapy such as cell-transplantation.