Spatiotemporal dynamic changes of ependymal cells after spinal cord injury in transgenic mice

BACKGROUND: Spinal cord ependymal cells exhibit neural stem/progenitor cell properties after injury in adult mammalian. OBJECTIVE: Ependymal cells were labeled with Nestin and Foxj1 transgenic mice to track the proliferation and differentiation fate of ependymal cells and their progeny after spinal cord injury in adult mice. METHODS: A 1-mm section was completely removed from the T₈ segment of the spinal cord in transgenic mice. Ependymal cells were dynamically observed by continuous intraperitoneal injection of BrdU at 1-7 days after spinal cord injury. At different time points (3, 7, 14, 28, 56 days) after spinal cord injury, the genetic fate mapping of ependymal cells in the lesion edge was observed by immunofluorescence staining of BrdU, GFAP, Tuj1, and NeuN. RESULTS AND CONCLUSION: (1) In the uninjured spinal cord, Nestin-positive ependymal cells were quiescent. Ependymal cells were activated and proliferated around the lesion edge at 3 days after spinal cord injury. (2) Approximately 3.3% of Nestin-positive ependymal cells expressed neuronal marker Tuj1 at 28 days after spinal cord injury. (3) At 56 days after injury, approximately 25.7% of Nestin-positive ependymal cells differentiated into astrocytes and formed the core of glial scar, participating in the formation of glial scar. (4) This article can provide theoretical basis for understanding the pathological process and new ideas for spinal cord injury repair by detecting the spatiotemporal changes, proliferation and differentiation characteristics of ependymal cells after spinal cord injury.