Diffusion tensor imaging predicting locomotor function recovery with 3D printing scaffold after spinal cord injury / 中国组织工程研究

ABSTRACT

BACKGROUND: Diffusion tensor imaging, as a relatively new method based on MRI, has become an important means of examination and diagnosis in the field of neuroimaging. OBJECTIVE: To investigate the role of using diffusion tensor tensor imaging data to predict 3D-bioprinted collagen/silk fibroin scaffolds in the locomotor function recovery after spinal cord injury. METHODS: Ordinary and 3D-bioprinted collagen/silk fibroin scaffold were prepared. Forty adult female SD rats provided by the Laboratory Animal Center of the Academy of Military Medical Sciences of the People’s Liberation Army were randomly divided into four groups with 10 rats in each group. In the sham operation group, only T10 vertebral plate was removed. In the model group, spinal cord injury was induced by total transection of spinal cord at T10 segment. In the ordinary collagen scaffold and 3D-printed scaffold groups, after induction of T10 spinal cord injury, ordinary collagen scaffold and 3D-printed scaffold were implanted, respectively. At 1, 2, 3, 4, 6 and 8 weeks after surgery, Basso, Beattie and Bresnahan (BBB) locomotor function scoring and oblique plate test of the hind limbs were carried out. At 8 weeks after surgery, electrophysiological test of the hind limbs was performed to evaluate locomotor function. At 8 weeks after surgery, diffusion tensor imaging of the lumbar spine was performed and the correlation between diffusion tensor imaging parameter and rat locomotor function was analyzed. Animal experiments were approved by the Animal Ethics Committee of Characteristic Medical Center of the Chinese people’s Armed Police Force (approval No. 27653/58). RESULTS AND CONCLUSION: (1) From 3 weeks after surgery, BBB score in the 3D-printed group was significantly higher than that in the model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). From 2 weeks after surgery, the slope angle in the 3D-printed scaffold group was significantly higher than that in the model and ordinary scaffold groups (P < 0.05 or P < 0.01). (2) The amplitude of motor evoked potential in the 3D-printed scaffold group was significantly greater than that in the model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). The latency of motor evoked potential in the 3D-printed scaffold group was significantly shorter than that in the model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). (3) Diffusion tensor imaging showed that the nerve fiber trajectories in the three groups were irregular and lacked the continuity of nerve fibers, but the number of regenerated nerve fiber bundles in the 3D-printed collagen scaffold group was greater than that in the model and ordinary collagen scaffold groups (P < 0.01). The fractional anisotropy at 9, 7.5, 4.5, -3, -6, -7.5, -9 mm from the center of spinal cord injury in 3D-printed collagen scaffold group was significantly higher than that in model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). (4) The BBB score, slope angle, amplitude of motor evoked potential, latency of motor evoked potential were positively correlated with the fractional anisotropy value of diffusion tensor imaging from head to tail of rats. (5) These results suggest that diffusion tensor imaging can be used as an effective predictor to evaluate the recovery of neurological function after spinal cord injury in experimental animals and clinical cases.