Abstract: The temporal expression of microRNA afer spinal cord ischemia/reperfusion injury is not yet fully understood. In the present study, we established a model of spinal cord ischemia in Sprague-Dawley rats by clamping the abdominal aorta for 90 minutes, before allowing reperfusion for 24 or 48 hours. A sham-operated group underwent surgery but the aorta was not clamped. Te damaged spinal cord was removed for hematoxylin-eosin staining and RNA extraction. Neuronal degeneration and tissue edema were the most severe in the 24- hour reperfusion group, and milder in the 48-hour reperfusion group. RNA amplifcation, labeling, and hybridization were used to obtain the microRNA expression profles of each group. Bioinformatics analysis confrmed four differentially expressed microRNAs (miR-22-3p, miR-743b-3p, miR-201-5p and miR-144-5p) and their common target genes (Tmem69 and Cxcl10). Compared with the sham group, miR- 22-3p was continuously upregulated in all three ischemia groups but was highest in the group with no reperfusion, whereas miR-743b-3p, miR-201-5p and miR-144-5p were downregulated in the three ischemia groups. We have successfully identifed the key genes expressed at different stages of spinal cord ischemia/reperfusion injury, which provide a reference for future investigations into the mechanism of spinal cord injury.

Key words: nerve regeneration, spinal cord injury, ischemia/reperfusion injury, mRNA, microRNA, bioinformatics, Tmem69, Cxcl10, transcriptome, microRNA arrays, neural regeneration