Objective: To establish spinal cord half-transection model in rhesus and investigate the Four neurological function and morphologic changes following spinal cord hemisection in rhesus.
Methods: Four cynomolgus monkeys were subjected to T-11 laminectomy and resection of a 1-mm length of hemispinal cord, while the controls underwent the identical laminectomy procedure but not the half-transection of the spinal cord. Neurological function of hindlimb was evaluated using modified Tarlov' grading, and cortical somatosensary evoked potentials (CSEP) were recorded in the 3rd postoperative month after spinal cord injury (SCI). The animals were sacrificed for histological examination. All the slices were processed with H-E staining and the number of neurons in the anterior horn of grey matter was counted.
Results: Irregular cavity was observed at the lesion site in the 3rd postoperative month. Distinct handicap of locomotor function in hindlimbs was observed in the half-transaction group immediately after SCI. As time went on, the locomotor function improved partially. Partial recovery of hindlimb function of adult monkey was noted in half-transection group from 14 days to 3 months after SCI, compared with that seen 24 hours postoperatively. The total number of neurons in the anterior horn of grey matter identical with hemitransection side was significantly smaller than that of the other side in the same segment (P < 0.05).
Conclusion: A reproducible model of SCI in the nonhuman primate was established. Spontaneous partial recovery of the ipsilateral hindlimb function occurred in the monkey with spinal cord hemisected during different periods, which indicated the functional plasticity in the spinal cord after hemisection injury.