Comparison of thyrotropin‐releasing hormone (TRH), naloxone, and dexamethasone treatments in experimental spinal injury

Abstract

Early treatment with either naloxone or TRH significantly improves neurologic outcome after experimental spinal injury. Because these previous studies used different injury variables, no conclusion could be made about the relative effectiveness of the 2 drugs. Naloxone and TRH treatment (each 2 mg/kg bolus, 2 mg/kg per h for 4 h) were directly compared; other cats received either dexamethasone (0.5 mg/kg bolus, 0.5 mg/kg per h) or saline. The spinal cord was traumatized at C-7 [cervical], using the Allen method; treatment was begun 1 h after injury. Neurologic function was graded between 0-10, using an ordinal rating scale. Both TRH- and naloxone-treated animals had significantly better functional scores than saline controls at 6 wk postinjury. TRH-treated cats also showed significantly better neurologic recovery than either naloxone- or dexamethasone-treated animals. The therapeutic benefit of TRH and naloxone in experimental spinal injury is confirmed. TRH treatment is most effective. Corticosteroid treatment was of no benefit in the present model.