Caractérisation comportementale, électrophysiologique et histologique d’un modèle animal de traumatisme spinal et cérébral concomitant
Spinal cord injuries (SCI) affect 17,810 people in North America every year. In this  condition, most individuals will lose the ability to perform simple motor actions and will  additionally suffer from sleep disturbances, emotional distress (anxiety and depression) and  cognitive impairments (memory). The occurrence of traumatic brain injury (TBI) in SCI population  is underestimated and missed-diagnosed in 12.4 to 74% of SCI patients, impeding the  implementation of optimal rehabilitation strategies and drug therapies. Although specialized care  is critically needed to improve rehabilitation outcomes in these patients, specialized dual diagnosis  care and evidence-based approaches for treatment are currently lacking. To address this knowledge  gap, we developed and characterized a novel rodent model of concomitant TBI and SCI. Using a  combination of behavioral and electrophysiological techniques, we examined the impact of  concomitant TBI and SCI on motor function, sleep, emotional state, and cognition. A group of rats  receiving concomitant TBI and SCI were compared with control groups that received SCI only or  surgical procedures without injuries (SHAM group). Global locomotion and sleep were evaluated  each week for one month by using the open-field test and electroencephalography to evaluate sleep  architecture, the spectral composition of vigilance states, including delta activity during non-rapid  eye movement (NREM) sleep. Emotional states and cognition were assessed at 6 weeks after  surgery. Anxiety and depression were tested using the open-filed and sucrose preference tests,  respectively. Working memory and spatial memory were evaluated by Y Maze test and spatial  object recognition test, respectively. We found that concomitant TBI-SCI and SCI alone both  impacted locomotor abilities, by comparison to the intact state. The duration and quality of  wakefulness and sleep were not significantly affected by SCI or TBI-SCI, despite spectral analysis  showing a tendency for TBI-SCI to increase NREM sleep delta activity. Neither concomitant TBI SCI nor SCI significantly impacted anxiety and depressive-like behaviors in comparison to the  SHAM group. By contrast, working memory was significantly impaired after TBI-SCI but was  preserved in SHAM and SCI groups. This result suggests that working memory could potentially  be used as a biomarker of these concomitant injuries. Further experiments are needed to fully  characterize this novel animal model. This includes performing more specific behavioral tests in  the acute and chronic stages after injury. Also, immunochemistry experiments directed on  molecular markers of neuro-inflammation and plasticity are needed. This novel animal model will  be useful to create and adapted diagnosis and therapeutic tools for TBI-SCI patients.
cognition locomotion rat spinal cord injury traumatic brain injury concomitant traumatic injury functional  recovery sleep cognition locomotion emotional state memory