Interleukin-17 expression in the injured site of a rat model of complete spinal cord transection / 中国组织工程研究

ABSTRACT

BACKGROUND:Intervention using known inflammatory transmitters has limitations on relieving secondary spinal cord injury. Interleukin-17 is an important proinflammatory cytokine, and is gradual y paid attention in the pathogenesis of central nervous system diseases. OBJECTIVE:To investigate the altered rule of interleukin-17 mRNA and protein in a rat model of acute spinal cord injury. METHODS:Healthy male Sprague-Dawley rats were randomly assigned to two groups. In the model group, rats were made into complete spinal cord transaction models. In the sham surgery group, only spinal dura mater was opened, but parenchyma was not injured. Basso, Beattie, Bresnahan locomotor rating scale was used to observe the effects of acute spinal cord injury on limb motor function of rats. Hematoxylin-eosin staining was used to observe histopathological changes at various time points after spinal cord injury. Real-time fluorescence quantitative PCR and western blotting were used to detect interleukin-17 mRNA and protein levels in each group at various time points after spinal cord injury. RESULTS AND CONCLUSION:Basso, Beattie, Bresnahan locomotor rating scaleBasso, Beattie, Bresnahan scores were 20 to 21 in the sham surgery group. Basso, Beattie, Bresnahan scores were 0 at 1 and 2 days after spinal cord injury. At 7 days, Basso, Beattie, Bresnahan scores were 0 to 3 (P<0.05). Hematoxylin-eosin staining results revealed that compared with the sham surgery group, inflammatory cel infiltration, neuronal and glial cel swel ing, and a reduced number of neuronal processes were observed at 6 hours after spinal cord injury. Gray matter and white matter were loose and vacuolated at 12 hours. Gliocyte proliferation and tissue fibrosis were apparent at 7 days. Real-time PCR results demonstrated that interleukin-17 mRNA appeared at 3 hours, and peaked at 6 hours (P<0.01), and then decreased. Interleukin-17 mRNA levels were similar to the sham surgery group at 7 days. Western blotting results revealed that interleukin-17 expression began to increase at 6 hours and peaked at 12 hours (P<0.05), and then reduced, and reached the levels in the sham surgery group at 7 days. Results indicated that tissue injury was most severe at 12 hours, and showed a time consistency with interleukin-17 expression. It is inferred that interleukin-17 is possibly involved in the process of secondary inflammatory reaction of spinal cord.