Diminution of Secondary Injury after Administration of Pharmacologic Agents in Acute Spinal Cord Injury Rat Model: Comparison of Statins, Erythropoietin and Polyethylene Glycol

ABSTRACT

STUDY DESIGN: An experimental animal study. OBJECTIVES: To evaluate and compare the neuroprotective effect of statins, erythropoietin and polyethylene glycol (PEG) after spinal cord injury (SCI). SUMMARY OF LITERATURE REVIEW There are few comparative studies of pharmacological agents for acute SCI. MATERIALS AND METHODS: Forty Sprague Dawley (SD) rats had a spinal cord injury at T9/10 using an Ohio State University (OSU) impactor. The animals were randomized to receive one of the following; simvastatin, erythropoietin, PEG or saline. A behavioral outcome assessment was performed on days 2, 4 and 7, and then every week using the Basso, Bresnahan, and Beattie (BBB) score and subscore. The animals were sacrificed at the end of 6 weeks and histologic assessment was performed to measure the areas of white and gray matter. RESULTS: For the animals treated with simvastatin, erythropoietin, PEG and saline, the mean BBB scores at 6 weeks post-injury were 13.2+/-0.1, 11.7+/-0.4, 13.3+/-0.3, and 11.4+/-0.2, and the BBB subscores were 9.2+/-1.1, 5.0+/-1.3, 9.1+/-1.1, 4.4+/-1.2, respectively. The BBB scores and BBB subscores were significantly higher in simvastain and PEG-treated animals (p<0.05). The areas of white matter at the lesion epicenter were 0.78+/-0.05mm2, 0.46+/-0.04 mm2, 0.68+/-0.15 mm2, and 0.41+/-0.04mm2 in the simvastatin, erythropoietin, PEG and saline groups, respectively. The simvastatin and PEG-treated animals showed increased sparing of the white matter at the injury epicenter and at 0.2mm rostral and 0.4mm caudal(p<0.05). CONCLUSION: Simvastatin and polyethylene glycol administration showed diminished secondary injury after SCI in rats. In addition, they showed almost the same efficacy. However, erythropoietin did not show neuroprotective effect.