Edaravone effects on the expression levels of collagen type I and IV after spinal cord injury in rats / 中国组织工程研究

ABSTRACT

BACKGROUND: Edaravone, an effective free radical scavenger, has been reported to significantly improve the rehabilitation of limb locomotion after spinal cord injury (SCI), but the underlying mechanism remains unclear. OBJECTIVE: To explore the mechanism underlying edaravone promoting the recovery of limb locomotion in rats with SCI by observing the Basso, Beattie, Bresnahan scores and expression levels of collagen type I and IV. METHODS: Thirty-six rats were randomly allocated into three groups (n=12 per group) sham group (laminectomy plus intraperitoneal injection of normal saline), model group (SCI model by NYU impactor plus intraperitoneal injection of normal saline), and edaravone group (SCI model by NYU impactor plus intraperitoneal injection of edaravone). All rats were given the administration at the 1stday post-SCI for consecutive 7 days. The Basso, Beattie, Bresnahan scores were tested at 1, 3, 5 and 7 days post treatment. On day 7, all rats were sacrificed to remove the spinal cord, and the morphology of neurons in the spinal cord were observed by Nissl staining; the expression levels of collagen type I and IV were detected by immunohistochemistry and western blot assays. RESULTS AND CONCLUSION: Compared with the model group, the Basso, Beattie, Bresnahan scores in the edaravone group were significantly increased at day 5 post treatment (P < 0.05). Nissl staining showed a clear boundary between grey matter and white matter, and a large nucleolus in the neurocytoplasm in the sham group; there was a complete structure of neurons, slight cellular swelling and small hematoma area in the edaravone group; many and large cavitations and swollen nucleus were found in the neurons, even without nucleolus. Immunohistochemistry and western blot assay results showed that the expression levels of collagen type I and IV in the edaravone group were significantly higher than those in the model group (P < 0.05). These results indicate that edaravone can promote the recovery of limb locomotion of rats with SCI,probably via up-regulating the expression levels of collagen type I and IV.