Determination of the ideal rat model for spinal cord injury by diffusion tensor imaging

Abstract

Four different spinal cord injury (SCI) models (hemisection, contusion, transection, and segment resection) were produced in male Sprague–Dawley rats to determine the most suitable animal model of SCI by analyzing the changes in diffusion tensor imaging (DTI) parameters both qualitatively and quantitatively in vivo. Radiological examinations were performed before surgery and weekly within 4 weeks after surgery to obtain DTI tractography, MRI routine images, and DTI data of fractional anisotropy (FA) and apparent diffusion coefficient (ADC). The Basso, Beattie, and Bresnahan scale was used to evaluate the locomotor outcomes. We found that DTI tractography tracked nerve fibers and showed conspicuous changes in the injured spinal cord in all the model groups, which confirmed that our modeling was successful. A decrease in FA values and an increase in ADC were observed in all the model groups after surgery. There were significant differences in FA and ADC between weeks 1 and 4 in both hemisection and contusion groups (P<0.05), whereas the differences in the transection and segment resection groups were not as remarkable (P>0.05). Basso, Beattie, and Bresnahan scores further proved the results because of a significant, positive correlation of the scores with FA (R=0.899, P<0.01) and a significant, negative correlation of the scores with ADC (R=−0.829, P<0.01). Therefore, the transection model, which is more quantified and stable within 4 weeks after injury according to the DTI and behavioral evaluation, should be used as the standard model for SCI animal testing.

Effect of hierarchically aligned fibrin hydrogel in regeneration of spinal cord injury demonstrated by tractography: A pilot study

“…Consistent with previous studies, the regeneration and reorganization of fibers resulted in an increase of FA in our AFG group. The FA values at week 1 post injury were abnormally high in some canines, which was inconsistent with other data showing the lowest FA values in the postoperative acute phase232425282930. This phenomenon has been reported before, but was not clearly explained631.…”

“…Recent studies indicate that quantitative DTI parameters are sensitive and specific biomarkers of spinal cord white matter integrity212223. Our data revealed a disruption of fibers on the hemisection side after the SCI, as well as regeneration of tract fibers at the chronic stage in canine 2, 4 and 8 of the AFG group.…”

“…DTI tractography can be used as a qualitative indicator of SCI to track the damaged nerve fibers visually and observe the lesion of axonal bundles clearly91112212223. Recent studies indicate that quantitative DTI parameters are sensitive and specific biomarkers of spinal cord white matter integrity212223.…”

“…The findings on tractography were in accordance with the motor performance and histological findings in our study. Previous studies have reported that injured spinal cords show a decrease in anisotropy, resulting from a disruption of longitudinally aligned axons and also exhibited a decrease in FA232425. In this study, we focused on tractography to visualize the configuration of traced fibers.…”

A novel composite type I collagen scaffold with micropatterned porosity regulates the entrance of phagocytes in a severe model of spinal cord injury

“…Using the same "resection model" described in this study, Wang et al reported spontaneous recovery of BBB of 0.75 6 0.5, 4 weeks after injury. 34 Yoshii 35 utilized a segment resection model of injury performed 10 days after thoracic spinal cord contusion and reported the absence of functional recovery 12 weeks postoperatively in the control group (BBB 0.2 6 0.5). Besides the absence of spontaneous recovery in untreated animals, some authors failed to observe functional motor recovery in injured rodents treated with scaffold-based strategy.…”