It has been demonstrated in paraplegic rats harboring an
epidural neoplasm that an antiedema effect can be achieved by in vivo treatment with either steroidal or
nonsteroidal anti-inflammatory agents or by
glutamate receptor antagonists. The effect of these treatments on vascular permeability of the normal and compressed spinal cord was quantitated by the
Evans blue dye technique.
Tumor-free and
tumor-bearing rats were assigned randomly for treatment as follows: 0.5 ml of saline or three doses at 12-hour intervals of either
dexamethasone (5 mg/kg),
methylprednisolone (30 mg/kg),
indomethacin (5 mg/kg every 24 hours), or a single dose of either
ketamine (110 mg/kg) or
MK-801 (3 mg/kg). Treatment was given at the onset of
paraplegia, and the animals were killed after 30 hours. In
tumor-bearing rats in the early symptomatic stage, extravasation of
Evans blue dye was 4.8 times greater than that of the normal cord (P less than 0.001) and at the onset of
paraplegia it was 9.9 times greater (P less than 0.0006).
Glucocorticoids and
indomethacin reduced
dye extravasation in paraplegic animals (P less than 0.01 and P less than 0.003, respectively), but the decreased permeability induced by
ketamine and
MK-801 did not reach the level of significance. In
tumor-free control animals permeability was not changed by administration of either
glucocorticoids or
indomethacin but was significantly reduced by
ketamine or
MK-801 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)