A modified compression model of spinal cord injury in rats: functional assessment and the expression of nitric oxide synthases

STUDY DESIGN: Experimental study. OBJECTIVES: To investigate a modified compression model of spinal cord injury (SCI) in adult rats by using a room-air- inflated Fogarty balloon catheter. SETTING: Kaohsiung, Taiwan. METHODS: The rats were divided into injury, sham-operated and control groups. A 2-French Fogarty catheter was passed from the lumbar spine (L3–L4) epidurally, with a mini-laminectomy under the microscope, to the level of thoracic spine (T6–T7). The actual site of the catheter tip was confirmed with X-ray. The balloon of Fogarty catheter then was inflated with room air, 0.2 ml, for 10 min. Mini-laminectomy was performed without inserting the catheter in the sham-operated group. Quantitative neurological outcomes were evaluated with the Basso, Beattie and Bresnahan (BBB) locomotor rating scale daily. The gene expression of nitric oxide synthases (NOSs) of the spinal cord was investigated at the end of the functional assessment. RESULTS: The mean BBB locomotor scores were 10±1.85 and 10±1.85, respectively, on days 1 and 3 in the injury group, and 21 and 20.29±0.69, respectively, in the sham-operated group. There was a significantly increased gene expression of inducible NOS in the SCI group compared with the sham-operated group and control group. Endothelial NOS gene expression was not significantly different among the groups. CONCLUSION: The functional and molecular assessments show that this modified balloon-compression technique is a reproducible, simple and inexpensive model of SCI in rats.