Establishment and evaluation of C5 dorsal spinal cord crush injury model in adult mice

English Keywords:Spinal cord injury  Mice  Axon regeneration  Model

English Abstract:

  【Abstract】 Objectives: To evaluate the C5 spinal cord crush injury(SCI)　model by behavior performance and histology in adult mice. Methods: A total of 16 adult mice(C57/Black) was randomly assigned into two groups, SCI group and Sham group with eight mice in each group. The spinal cord crush injury(the dorsal and dorsal lateral axons were cut) model at C5 was established by using a modified FST DUMONT 5 surgical forceps. In the Sham group, the lamina was removed without damaging the spinal cord. The behavior performance was evaluated by rearing cylinder, horizontal ladder, and stair case pellet reaching. The axons of the corticospinal tract(CST) and the rubrospinal tract(RST) were observed 8 weeks after operation by using BDA anterograde tracing. Results: The hind limb locomotor function was rarely affected in both groups and showed similar BMS scores after injury. However, the fine skilled motor functions were obviously impaired by this axonal crush. Specifically, animals in the SCI group showed significant decrease of the upper limbs usage on the injured side and the limitation of grooming actions in the rearing cylinder, when compared with the Sham group at all time points（P<0.05）. Similarly, when walking across the horizontal ladder, mice in the SCI group showed significant accuracy reduction in gripping the beam, especially in the injured side, when compared with the Sham group at all time points(P<0.05). The ability of grasping food pellets in the SCI group significantly decreased when compared with the Sham group at all time points(P<0.05). These impaired motor functions reached the summit 3 days after injury and started to recover 2 weeks later. However, they did not go back to normal even 8 weeks after injury. No regeneration was observed neither in the corticospinal tract nor in the rubrospinal tract 8 weeks after injury. Conclusions: A stable, reliable and clinical relevant animal model of cervical spinal cord injury was successfully established, which was suitable for axon regeneration researches.