DTI-MRI at 2 days after spinal cord injury accurately predicts long-term locomotor function recovery in rats.

OBJECTIVE: Spinal cord injury (SCI) damages an individual's sensory, motor, and autonomic functions and represents a social emergency, mostly in developed countries. Accurate and timely diagnosis of the severity of SCI must be carried out as quickly as possible to allow time for drug and therapy testing in the early stages after injury. MATERIALS AND METHODS: Male Dark Agouti (DA) rats underwent spinal cord cryoinjury at the T13 level of the spine. Under typical conditions, in vivo magnetic resonance imaging (MRI) T2 and echo-planar imaging - diffusion tensor imaging (EPI-DTI) examinations were conducted. This involved the reconstruction of nerve tracts and the measurement of the fractional anisotropy (FA) index, as well as measurements of the ratio of Hyper/Hypo intensive areas and spinal cord injury severity scores. RESULTS: Our study shows that, after cryoinjury, the FA significantly decreased in all animals. An increase in FA level, derived from EPI-DTI within 2 days after SCI, accurately predicts long-term locomotor function recovery. In rats with higher FA, recorded on day 2 after injury, complete restoration of locomotor function was observed, while at low FA values, the animals maintained stable monoplegia. CONCLUSIONS: Our results, though validating the T2 10-grade MRI scale for SCI, indicate that FA would represent the MRI technical instrument, which would better monitor the evolution of SCI and, accordingly, better objectively evaluate the impact of potentially therapeutic protocols for spinal cord traumatic injury. Despite the results achieved, significant difficulties must be overcome on the way to successful clinical implementation of the findings in humans.

CSF - injected contrast medium enhances post-traumatic spinal cord cysts. An experimental study in rats.

OBJECTIVE: Spinal cord injury (SCI) is still one of the most challenging problems in neurosurgical practice. One of the major obstacles to neural regeneration following trauma is the formation of glial scarring and post-traumatic cysts which acts against proper growth of axons through the site of injury. Cerebrospinal fluid (CSF) delivery of bioactive agents into cystic cavities could represent a promising therapeutic strategy. In the present study, we investigated specifically the dynamics of intradural delivery of contrast medium and its relocation into post-traumatic cysts in an experimental model of spinal cord cryoinjury in rats. MATERIALS AND METHODS: 32 male Sprague Dawley SPF rats were submitted to injury as previously described. Omnipaque-240 was injected either into the cisterna magna or at the level of the cauda equina. Subsequently, cerebral CT scan examinations were performed in order to check the CSF dynamics of the contrast medium. RESULTS: There was a steady accumulation of contrast medium into post-traumatic cysts as early as five minutes after injection. A dosage of 65 mg of iodine per kilogram ensured an adequate feeling of the cysts at an average of 30 minutes. CONCLUSIONS: Our data indicate that intraspinal injection of bioactive agents can easily reach the site of injury and fill post-traumatic cysts. This could represent an interesting potential therapeutic protocol for SCI.

Surgical Simulation of a Posttraumatic Spinal Cord Glial Scar in Rats.

We developed and verified an original, minimally invasive method for surgical simulation of a posttraumatic spinal cord glial scar in rats. The model is intended for use as a biological platform for testing the stimulation of regenerative processes in the central nervous system. Unification of the model enables one to achieve versatility both for implantation techniques and for the development of system-action approaches. Faced with a standard structural defect of the spinal cord, researchers will have the unique opportunity to test in vivo promising methods for spinal function recovery in the posttraumatic period. We developed anesthetic support, surgical tactics, and a set of rehabilitation measures for the chronic postoperative period. Experimental exposure effects were preliminarily assessed in vivo using a standard technique for recording the motor activity of rats in the postoperative period of spinal cord injury. Our final conclusions were drawn based on an analysis of histological sections of the rat spinal cord glial scar in three mutually perpendicular planes.

Experimental Models of Spinal Cord Injury in Laboratory Rats.

Pathologies associated with spinal cord injury are some of the leading diseases in the world. The search for new therapeutic agents and 3D biodegradable materials for the recovery of spinal cord functions is a topical issue. In this review, we have summarized the literature data on the most common experimental models of spinal cord injury in laboratory rats and analyzed the experience of using 3D biodegradable materials (scaffolds) in experimental studies of spinal trauma. The advantages and disadvantages of the described models are systematically analyzed in this review.