Graded Spinal Cord Contusive Rat Model by a Weight-drop Device

ABSTRACT

OBJECTIVE: To investigate the reproducibility of graded spinal cord contusion by a weight-drop device, and to establish a graded spinal cord contusive rat model based on the functional analysis and morphometric measurement. METHOD: The weight-drop device developed was composed of impactor with a guidance rod, stereotaxic frame and spine stabilizing device. We investigated the reproducibility of impact by reliability analysis two weeks later. Thirty Sprague-Dawley rats were injured by the weight-drop device from the height of 12.5, 25.0 and 50.0 mm. The three groups of each drop-height (n=10) as well as laminectomized sham group (n=10) were subjected to functional analysis by Basso Beattie Bresnahan Locomotor Scales (BBB scales) and inclined plane test after contusion for four weeks. The morphometric measurement was performed at regularly spaced intervals including the epicenter according to the graded drop-height. RESULTS: The impact of weight-drop was significantly increased according to the drop-height (p <0.05) and revealed high reproducibility. The changes of BBB scales and maximal angle of inclination had an inverse correlation with the contusion severity (p <0.05). There was an inverse correlation between the amount of residual white matter and drop-height (p <0.05). CONCLUSION: The weight-drop device newly developed provides a constant and reproducible spinal cord contusion model.