ObjectiveTo systematically profile and characterize the circular RNA (circRNA) and microRNA (miRNA) expression pattern in the lesion epicenter of spinal tissues after traumatic spinal cord injury (TSCI) and predict the structure and potential functions of the regulatory network.MethodsForty-eight adult male C57BL/6 mice (weighing, 18-22 g) were randomly divided into the TSCI (n=24) and sham (n=24) groups. Mice in the TSCI group underwent T8-10 vertebral laminectomy and Allen’s weight-drop spinal cord injury. Mice in the sham group underwent the same laminectomy without TSCI. The spinal tissues were harvested after 3 days. Some tissues were stained with HE staining to observe the structure. The others were used for sequencing. The RNA-Seq, gene ontology (GO) analysis, and circRNA-miRNA network analyses (TargetScan and miRanda) were used to profile the expression and regulation patterns of network of mice models after TSCI.ResultsHE staining showed the severe damage to the spinal cord in TSCI group compared with sham group. A total of 17 440 circRNAs and 1 228 miRNAs were identified. The host gene of significant differentially expressed circRNA enriched in the cytoplasm, associated with positive regulation of transcription and protein phosphorylation. mmu-miR-21-5p was the most significant differentially expressed miRNA after TSCI, and circRNA6730 was predicted to be its targeted circRNA. Then a potential regulatory circRNA-miRNA network was constructed.ConclusionThe significant differentially expressed circRNAs and miRNAs may play important roles after TSCI. A targeted interaction network with mmu-miR-21-5p at the core of circRNA6730 could provide basis of pathophysiological mechanism, as well as help guide therapeutic strategies for TSCI.