A MOUSE MODEL OF GRADED CONTUSIVE SPINAL-CORD INJURY

A mouse model of spinal cord injury (SCI) could further increase our b asic understanding of the mechanisms involved in injury and recovery b y taking advantage of naturally-occurring and genetically engineered m utations available in mice. We have, therefore, investigated whether m ethods used to produce and evaluate graded experimental contusive SCI in the rat could be modified to produce a mouse model of traumatic SCI . C57BL6 mice were anesthetized with 2,2,2-tribromoethanol and a restr icted laminectomy performed at the T8 vertebral level, The spinal colu mn was stabilized and a weight drop technique used to produce contusiv e injury. Experimental groups were distinguished by the amount of weig ht or the height from which the weight was dropped onto an impounder r esting on the dura (Ig x 2.5 cm, 2 g x 2.5 cm, 3 g x 2.5 cm, and 3 g x 5.0 cm). Functional deficits over time were examined up to 28 days af ter SCI by testing hindlimb reflex responses and coordinated motor fun ction. Chronic lesion histopathology was evaluated by light microscopy and analyzed with morphometric techniques. All groups demonstrated pr ofound functional deficits after injury followed by gradual recovery. Recovery correlated with the weight dropped and percent of white matte r spared that was 41.3 +/- 6.0% (mean +/- SEM) in the 2 g x 2.5 cm gro up and 24.3 +/- 5.0% in the 3 g x 2.5 cm group. A replicate experiment confirmed reproducibility of the injury, This new mouse model of cont usive SCI could pave the way for in vivo studies of the effect of gene tic modifications produced by specific mutations on injury and recover y processes after spinal cord trauma.