Persistent oppression and simple decompression both exacerbate spinal cord ascorbate levels

Background: Surgical decompression after acute spinal cord injury has become the consensus of orthopaedic surgeons. However, the choice of surgical decompression time window after acute spinal cord injury has been one of the most controversial topics in orthopaedics. Objective: We apply an online electrochemical system (OECS) for continuously monitoring the ascorbate of the rats' spinal cord to determine the extent to which ascorbate levels were influenced by contusion or sustained compression. Methods: Adult Sprague-Dawley rats (n=10) were instrumented for ascorbate concentration recording and received T11 drop spinal cord injury (SCI). The Group A (n=5) were treated with immediately decompression after SCI. The Group B (n=5) were contused and oppressed until 1 h after the injury to decompress. Results: The ascorbate level of spinal cord increased immediately by contusion injury and reached to 1.62 μmol/L ± 0.61 μmol/L (217.30% ± 95.09% of the basal level) at the time point of 60 min after the injury. Compared with the Group A, the ascorbate level in Group B increased more significantly at 1 h after the injury, reaching to 3.76 μmol/L ± 1.75 μmol/L (430.25% ± 101.30% of the basal level). Meanwhile, we also found that the decompression after 1 hour of continuous compression will cause delayed peaks of ascorbate reaching to 5.71 μmol/L ± 2.69 μmol/L (627.73% ± 188.11% of the basal level). Conclusion: Our study provides first-hand direct experimental evidence indicating ascorbate is directly involved in secondary spinal cord injury and exhibits the dynamic time course of microenvironment changes after continuous compression injury of the spinal cord.