Serum Leptin Levels Following Acute Experimental Spinal Cord Injury

Abstract

BACKGROUND AND PURPOSE: Cortisol has neuroprotective effects. We monitored the serum cortisol levels after cervical and thoracic spinal cord injury (SCI) in four groups of rats. MATERIAL AND METHODS: Forty male Sprague-Dawley rats were randomized to four groups. The control group received neither laminectomy nor SCI. The sham group received laminectomy without SCI. The cervical spinal trauma group received a C5-C6 laminectomy and spinal trauma at this level. The thoracic spinal trauma group received a T6-T7 laminectomy and spinal trauma. Blood samples were drawn 2, 6, 12 and 24 hours after surgeries and assayed immediately. RESULTS: The level of cortisol in the cervical spinal trauma group was highest at the second hour of the experiment and the lowest in control and sham-operated groups at the same time. At the sixth hour, cortisol levels increased in control and sham-operated groups, decreased in the cervical group and did not change in the thoracic group. At the 12th hour, cortisol levels in control and sham-operated groups decreased, but increased in thoracic and cervical groups. At the 24th hour, serum cortisol levels in thoracic and cervical groups decreased but did not change significantly in control and shamoperated animals. CONCLUSIONS: Activation of endogen cortisol secretion of the organism starts immediately after the SCI injury and throughout the experiment the serum cortisol levels in neurotrauma groups remained high compared with the control and sham-operated groups. At the beginning, the level of neurological lesion (cervical or thoracic) affected differently the level of serum cortisol at a statistically significant level but this difference disappeared at the 6th hour.