Models of Spinal Cord Injury: Part 1

Abstract

Testing of potential therapies for spinal cord injury has been significantly hampered by the unavailability of a standardized, reproducible animal model with predictable outcome at a given force of injury (dose-response). The rat was selected in the development of this model in preference to larger animals for economy and availability; this permits use of large numbers of animals to increase statistical validity. In the experiments reported in this article, a static load method (weight placed gently on cord) of inducing cord injury was evaluated. A total of 198 Sprague-Dawley rats were used. Under general anesthesia, a one-level laminectomy was carried out at T-12 with the dura mater intact. Weights varying from 80 to 150 g were lowered onto the dorsal surface of the intact dura mater for durations of 0 to 300 seconds. Recovery of motor function was assessed for up to 8 weeks using two behavioral tests, a modified Tarlov scale and an inclined plane test of hind limb motor function. A statistically significant relationship was found between force of injury and motor recovery as measured by the Tarlov scale, but this did not correlate with inclined plane performance; the duration that the weight rested on the cord did not influence outcome. Pathologically, there was variation in the extent of damage for a given injury load. A semiquantitative pathological assessment of cord injury showed a statistically significant correlation between pathological score and behavioral deficit as measured by the Tarlov scale, but this did not correlate with inclined plane performance. In view of these deficiencies, the static load technique does not seem to be an ideal model for spinal cord injury research.

Preventive Effect of Erythropoietin on Spinal Cord Cell Apoptosis Following Acute Traumatic Injury in Rats

“…Each rat was mounted on an apparatus to induce injury to the spinal cord by the static load technique. [13][14][15] Following pentobarbital sodium anesthesia by intraperitoneal injection, a laminectomy was performed at T8 and T9 to expose the dorsal aspect of the dural tube. The dura was compressed by gently lowering a 120 g weight onto a 2 ϫ 3 mm surface area of the spinal cord for 2 minutes using a compression apparatus to produce a severe SCI.…”

EFFECTS OF COMBINED AND INDIVIDUAL USE OF NMDA RECEPTOR ANTAGONIST MAGNESIUM SULPHATE AND CASPASE-9 INHIBITOR z-LEDH-fmk IN EXPERIMENTAL SPINAL CORD INJURY

“…Weightdrop method was criticized because of the difficulty to standardize the trauma. [15,49] The motor grading scales were low for all groups (1.0) except the sham-operated group and remained the same for the rest of the study, although there were progress in inclined-plane scores. Tail movement lasted for 3-4 seconds 13 seconds after the clip was applied, then the tail remained atonic indicating paraplegia.…”

Effects of low-dose methotrexate in spinal cord injury in rats

“…Each section was evaluated by an experienced pathologist blinded to the groups and test materials. For histopathological evaluation of the SCI, a grading system described by Black et al [8] was applied to all specimens as follows ( macrophage and/or histiocyte infiltration with white matter loss and central cavitation.…”

“…[8] Biochemical determinations were carried out by two biochemists blinded to the animal groups and test materials. Frozen tissue samples were weighed and homogenized in 1:10 (w:v) potassium phosphate buffer (50 mM, pH: 7.4) using a dounce homogenizer.…”