Rat Spinal Cord Injury Experimental Model

Spinal cord injuries (SCI) with their tragic consequences belong to the most serious pathological conditions. That is why they have stimulated basic research workers, as well as health care practitioners, to search for an effective treatment for decades. Animal experimental models have been essential in these efforts. We have jointly decided to test and standardize one of the spinal cord injury compression models in rats. Twentythree adult female Wistar rats weighing 250-320 g were utilized. Employing general anaesthesia along with a mixture of sevoflurane with O₂, 2 rats (sham controls) had their vertebral arch of either Th8 or Th9 vertebra removed (laminectomy). The other 21 experimental rats with similar laminectomies were divided into 3 subgroups (n = 7) which received compression impact forces of 30, 40 or 50 g (subgroups-1, -2, and -3, respectively) applied on their exposed spinal medulla for 15 minutes. All rats were observed for 28 days after the experimental procedure and their motor functions were assessed by the Basso, Beattie, Bresnahan (BBB) test 6 hours, 7, 21 and 28 days after the simulated SCI. All 23 rats survived the surgical procedures. The control rats were without any neurological deficits. There were, in every experimental subgroup, 1 or 2 rats with extreme BBB scores. So the rats with the maximum and minimum BBB values were excluded. Then, the results acquired in the residual 5 rats in each group were averaged and statistically analysed by the Tukey multiple comparisons test. Statistically significant intersubgroup differences were found at all survival times equal to or longer than 7 post SCI days. The goal of the SCI experiment was to generate a reproducible and reliable, submaximal spinal cord trauma model. The statistical analyses demonstrated that this objective was best achieved in the subgroup-2 with the 40 g compression.