Spinal blood flow in 24-hour megadose glucocorticoid treatment in awake pigs.
OBJECTIVE
Because of the controversy regarding the benefits of 24-hour administration of methylprednisolone in patients with spinal cord injury (SCI), it is important to investigate its mechanism of action and side effects. This study was conducted to determine if high-dose methylprednisolone modulates neural and vertebral blood flow in an awake large-sized animal model without SCI.


METHODS
From a group of 18 immature female domestic pigs born to nine different litters, nine animals were randomly allocated to receive methylprednisolone treatment, whereas their nine female siblings served as controls. Drug or placebo was applied in a blinded fashion by a third person not involved in the study. The following treatment for SCI, as suggested by the North American Spinal Cord Injury Study, was administered to the awake pig: methylprednisolone (30 mg/kg of body weight) was infused into the jugular vein during a 15-minute period, followed by a 45-minute pause, and the infusion was maintained over a 23-hour period at a dose of 5.4 mg/kg body weight/hour. By means of the radioactive tracer microsphere technique, spinal cord blood flow (SCBF) was measured in the awake standing pig in the cerebrum, and in spinal gray and white matter, nerve roots, endplates, cancellous bone, cortical shell, and T12-L2 discs. Blood flow was measured before, 1 hour after initiation of infusion, and 24 hours postinfusion. Examination of blood flow in the neural and vertebral tissue samples, as well as of central hemodynamics, revealed no significant difference between the experimental and control groups, and this parity was maintained throughout the experimental phases.


CONCLUSIONS
In the awake pig model, 24-hour methylprednisolone treatment does not modulate cerebral or SCBF, nor does it increase the risk for vertebral osteonecrosis by producing vertebral ischemia.
Drescher
Wolf R
WR
Institute of Experimental Clinical Research, Department of Orthopedics, Spine Section, Aarhus University, Aarhus, Denmark. WolfDrescher@hotmail.com
Weigert
Karen P
KP
Bünger
Mathias H
MH
Hansen
Ebbe S
ES
Bünger
Cody E
CE
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001921:Brain / Q000098:blood supply; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D007262:Infusions, Intravenous; D007511:Ischemia; D008775:Methylprednisolone / Q000008:administration & dosage / Q000009:adverse effects*; D010020:Osteonecrosis; D012039:Regional Blood Flow; D012307:Risk Factors; D013116:Spinal Cord / Q000098:blood supply*; D013119:Spinal Cord Injuries / Q000188:drug therapy; D013131:Spine; D013552:Swine
D000893:Anti-Inflammatory Agents; D008775:Methylprednisolone