关键词: 颈脊髓损伤, 单侧挫伤, 兔, MRI, 组织学

Abstract:

Objective 　To establish a unilateral cervical spinal cord contusion injury model in rabbits, and characterize the MRI and histology of two-level spinal cord contusion at 24 hours after injury. Methods　Twenty-two male New Zealand rabbits were randomly assigned into the moderate lesion group (n=9), the severe lesion group (n=9) and the sham group (n=4), respectively. All animals in the moderate group were subjected to 2.0 mm contusion at 500 mm/s on the left of C5 spinal cord, while all animals in the severe group to 2.8 mm contusion. The flat head impactor was 3.0 mm in diameter and was  driven by an electromagnetic-servo material testing machine. The sham group exposed the spinal cord without contusion. Post-injury MRI was scanned and analyzed for 2 animals per group. Spinal cord samples of all animals were harvested 24 hours after injury, and analyzed the hemorrhagic area of the cord on cross section of the epicenter.　 Result　The peak force and actual contusion displacement were (2.47±0.39) N and (1.99±0.02) mm in the moderate group, and (5.16±0.82) N and (1.99±0.02) mm in the severe group, respectively. There was significant difference in the peak force between groups (P<0.05). There were high and low intensity T2-weighted signal in the C5 cord on post-operative MRI in the two injured groups. Histological analysis showed that there were hematoma and tissue damage on the left side of spinal cord in two injured groups, and hHematoma area was (0.012±0.006) mm2 in the moderate group and (0.039±0.006) mm2 in the severe group. There was significant difference in hematoma area between groups (P<0.05).　Conclusion　The study establishes a unilateral cervical spinal cord contusion model with displacement control and at high speed. Different unilateral cervical spinal cord contusions showed different degrees of lesions in peak force, MRI and histology.

Key words: Cervical spinal cord injury, unilateral contusion, rabbit, MRI, histology