ABSTRACT
Sensorimotor disturbances continue to represent one of the most debilitating and widely reported complications in patients suffering mild traumatic brain injuries (mTBI). Loss of peripheral neuronal function at sites distal and disconnected to the central nervous control central centers is well documented. Distal muscular atrophy, complex regional pain symptoms, and poor wound healing are just a few of the many complications with often more severe secondary complications such decubitus ulcers and osteomyelitis seen at sites in the body distal to the center of injury. MRI has been widely established as a diagnostic and therapeutic planning tool in patients and animal models with neuronal disease. However, studies investigating the neural correlates of spinal cord changes after TBI are lacking. Here, we used T2 MR imaging to determine the effects of mTBI on the morphology and inflammatory changes of the spinal cord. We hypothesize that rats receiving mTBI utilizing a controlled cortical impact (CCI) contusion will demonstrate T2 signal changes at distal locomotor centers in the spine. Experimental mTBI and sham groups of Sprague-Dawley rats were used (n = 2 sham and 4 experimental). A mild CCI was applied to the right brain cortex. Rats were sacrificed at 60 days post injury and spinal cords harvested for ex vivo MRI T2 analysis. Focal areas/lesions of increased T2 hyperintensity were noted in mTBI injured rats (n = 4).
Experimental group of rats also demonstrated secondary spinal cord locomotor and sensation adverse effects clinically. MR imaging showed volumetric reductions and T2 signal changes in the cervical, thoracic, and lumbar segments of the spinal cord at 8 weeks’ post-injury. T2 intensity values were elevated in all experimental groups in comparison to the sham group within the distal cord, suggesting that remote CCI causes secondary spinal cord inflammation and neurodegeneration at distant sites. These findings also further support the idea that the most peripheral nerves and spinal cord will be most negatively affected by a TBI. While our research is in its preliminary stages, our results further confirm that mTBI has more far reaching effects than previously understood. T2 MRI is an effective tool to assess the extent of spinal cord injury related to antecedent TBI.
