Rehabilitation training combined with neurotrophin 3-chitosan scaffolds enhanced skeletal muscle morphology and functional recovery in rats with spinal cord injury / 中国组织工程研究

ABSTRACT

BACKGROUND: Previous studies have shown that neurotrophin 3 (NT3)-chitosan can induce endogenous neurogenesis and axon regeneration in rats with spinal cord injury, and promote recovery of motor and sensory functions in rats. OBJECTIVE: To observe the effect of rehabilitation training combined with NT3-chitosan biomaterial scaffold on skeletal muscle morphological changes and functional recovery in rats with complete spinal cord injury. METHODS: Fifty adult female Wistar rats were randomly divided into five groups, 10 in each group. The sham group was not modeled; the remaining four groups were prepared with T7-T8 complete 5-mm spinal cord injury model, and the lesion control was not performed any intervention after modeling. The other three groups were given rehabilitation training, NT3-chitosan active biomaterial scaffold, NT3-chitosan active biomaterial scaffold combined with rehabilitation training intervention. Rehabilitation training started 2 weeks after modeling. Before operation, 2, 4, 6, 8, 10, and 12 weeks after operation, all of rats were subjected to double-blind open-field BBB scores. After 12 weeks, the skeletal muscles of the hind limbs (tibialis anterior muscle, gastrocnemius muscle, and soleus muscle) were taken for hematoxylin-eosin staining and acetylcholinesterase staining. The changes in muscle atrophy and motor endplates were assessed in each group. The experimental plan was approved by the Animal Experiment Committee of Capital Medical University (approval No. AEEI-2018-105). RESULTS AND CONCLUSION: (1) The BBB score at each time point in the sham group was higher than that in the other four groups (P < 0.05); and the scores at 8, 10, and 12 weeks after the NT3-chitosan combined rehabilitation training group were higher than the lesion control group, the lesion control combined rehabilitation training group, and NT3-chitosan group (P < 0.05). (2) At 12 weeks after operation, hematoxylin-eosin staining showed that the cross-sectional area and diameter of muscle fibers of each skeletal muscle were smaller in the other four groups than that in the sham group (P < 0.05). The cross-sectional area and diameter of muscle fibers of each skeletal muscle in the NT3-chitosan combined rehabilitation training group were higher than the lesion control group, the lesion control combined rehabilitation training group, and NT3-chitosan group (P < 0.05). (3) At 12 weeks after operation, the acetylcholinesterase staining showed that the average optical density of the acetylcholinesterase on motor endplate of the muscle was lower in the other four groups than that in the sham group (P < 0.05); the average optical density of the acetylcholinesterase of the motor endplate in the NT3-chitosan combined rehabilitation training was significantly higher than that in the lesion control, lesion control combined rehabilitation training, and NT3-chitosan groups (P < 0.05). (4) The results show that NT3-chitosan combined with rehabilitation training can effectively prevent muscular atrophy of hind limb skeletal muscles in rats with complete spinal cord injury, improve the average optical density of the acetylcholinesterase of the motor endplate, reduce neuromuscular joint degeneration, and improve rat hindlimb motor function.