Verhandelingen - Koninklijke Academie voor Geneeskunde van België vol:57 issue:4 pages:315-49
A new method was briefly described for microdialysis of the spinal cord in freely moving rats with a removable probe. The technique allowed to measure interleukin-6(IL-6) release in the extracellular fluid of the spinal cord when the rats were fully recovered from the operation and while they were freely moving. The injury-inducing effect of performing microdialysis of the spinal cord in rats was studied. In conclusion, long-term presence of a probe in the spinal cord causes a lesion which is functionally of borderline significance. The Tarlov score and the performance in the inclined plane test can be used as valid and reliable indicators of residual spinal cord function after injury in rats. Using the microdialysis technique, it was shown that IL-6 is secreted in injured spinal cord. However, we could not show that mechanical trauma induces IL-6 secretion. Methylprednisolone (MP), which has a known neuroprotective effect in SCI in rats, was administered (30 mg/kg body weight, 0.4 ml, i.v., 45 min after injury) to rats with a 50g static load-induced SCI. The control group received saline. According to a randomized, blinded protocol, the rats (n=21) were subjected to the inclined plant test and evaluated in open field with the Tarlov score before and after injury (day minus 1, days 1,2,3,4,7,14, and 21). Mortality before day 21 was registered. In conclusion the data show that one intravenous dose of MP increases survival rate in rats with SCI. The data confirm that MP diminishes tissue damage in SCI. The present study provides evidence for an in vivo neuroprotective action of IL-6. The spinal cords of 42 Wistar rats were injured in the same way as in the previous experiment, and the evaluation of the animals was also the same. In conclusion, the results suggest that IL-6, locally administered into the spinal cord, diminishes tissue damage and augments chances of survival after SCI.