Characterization of a novel bidirectional distraction spinal cord injury animal model

• Published in: Journal of neuroscience methods 2011-04, Vol.197 (1), p.97-103
• Main Authors: Seifert, J.L., Bell, J.E., Elmer, B.B., Sucato, D.J., Romero, M.I.
• Format: Article
• Language: English
• Subjects: Animals; Disease Models, Animal; Distraction SCI; Female; Rats; Rats, Long-Evans; Spinal Cord - pathology; Spinal Cord - physiopathology; Spinal Cord Injuries - diagnosis; Spinal Cord Injuries - pathology; Spinal Cord Injuries - physiopathology; Spinal cord injury; Spine - pathology; Spine - physiopathology; Spine - surgery; Traction - adverse effects; Traction - methods
• ISSN: 0165-0270; 1872-678X
• DOI: 10.1016/j.jneumeth.2011.02.003

► The device produced a controlled, consistent and reproducible distraction injury. ► A distraction distance of 7mm resulted in hind limb paralysis (BBB average=0.17). ► GFAP analysis showed reactive astrocytes present, confirming injury induction. ► H&E histological evaluation revealed drastic cellular loss indicating severe injury. Scoliosis corrective surgery requires the application of significant multidirectional stress forces, including distraction, for correction of the curved spine deformity and the application of fixation rods. If excessive, spine distraction may result in the development of new neurological deficits, some as severe as permanent paralysis. Current animal models of spinal cord injury, however, are limited to contusion, transection, or unidirectional distraction injuries, which fail to replicate the multidirectional forces that occur during spine corrective surgery. To address such limitation, we designed a novel device that relies on intervertebral grip fixation and linear actuators to induce controllable bidirectional distraction injuries to the spine. The device was tested in three (i.e., 3, 5, and 7mm) distention paradigms of the rat T9–T11 vertebra, and the resulting injuries were evaluated through electrophysiological, behavioral, and histological analysis. As expected, 3mm bilateral spine distractions showed no neurological deficit. In contrast, those with 5 and 7mm showed partial and complete paralysis, respectively. The relationship between the severity of the spine distraction and injury to the spinal cord tissue was determined using glial fibrillary acidic protein immunocytochemistry for visualization of reactive astrocytes and labeling of ED1-positive activated macrophages/microglia. Our results demonstrate that this device can produce bidirectional spine distraction injuries with high precision and control and, thus, may be valuable in contributing to the testing of neuroprotective strategies aimed at preventing unintended new neurological damage during corrective spine surgery.