Failure of blood transfusion or naloxone to improve clinical recovery after experimental spinal cord injury.

Thirty adult Wistar rats underwent an extradural clip compression injury of 50 g of force for 1 minute at T-1. After injury, the animals were randomly separated into three groups: the control group received a saline infusion for the 2-hour treatment period; the second group was given a blood transfusion over 2 hours titrated to maintain mean systemic arterial pressure (MSAP) at preinjury levels; and the third group received an intravenous bolus dose of naloxone (10 mg/kg), followed by a 2-hour infusion of intravenous naloxone (2 mg/kg/minute). The rats were observed postoperatively for 15 weeks, during which their clinical recovery was measured weekly by the inclined plane technique. At 15 weeks, the spinal cords were removed and prepared for histological assessment. The blood pressure before, during, and immediately after injury did not differ statistically among the three groups. During the initial 2 hours after injury, blood transfusion produced a significant increase in MSAP (P less than 0.02) and hematocrit (P less than 0.001), but naloxone infusion did not result in a significant change in MSAP. Performance on the inclined plane at 15 weeks was 35.6 +/- 6 degrees, 32.7 +/- 4 degrees, and 36.1 +/- 6 degrees for the control, transfusion, and naloxone groups, respectively, and no significant differences were found (P greater than 0.05). Histological examination confirmed a consistent injury of moderate severity in all three groups with no major differences among groups. Thus, this study demonstrates no significant clinical benefit either from a blood transfusion to maintain MSAP or from naloxone given by bolus and infusion after an extradural clip compression injury of the rat spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)