Previous studies using
steroids for experimental focal
stroke have demonstrated conflicting results, possibly related to dose used or ischemic models employed. In this study we examined high-dose
methylprednisolone treatment following permanent and temporary focal
cerebral ischemia in the rat. Focal
stroke was induced in spontaneously hypertensive rats by permanent right common carotid and either permanent or 3 h of temporary middle cerebral artery (MCA) occlusion.
Methylprednisolone (105 mg/kg) was administered intra-arterially.
Infarct volume was measured at 24 h after permanent and temporary MCA occlusion.
Cerebral edema was determined by measuring right and left hemispheric volumes and water content 24 h after permanent MCA occlusion in one experiment.
Methylprednisolone, whether administered in divided doses over 12 h (n = 15 in each group) or a single bolus (n = 9 per group), had no effect on
infarct volume after permanent MCA occlusion.
Methylprednisolone treatment also had no influence on
cerebral edema (n = 9 per group). In two different experiments,
methylprednisolone given in divided doses over 12 h (n = 11, n = 25) after temporary MCA occlusion decreased
infarct volume (P < 0.05) by 20% compared with saline controls (n = 10, n = 25). High dose
methylprednisolone decreased
infarct volume following temporary, but not permanent, focal
ischemia. The benefit suggests that high dose
methylprednisolone may prove useful clinically if reperfusion can be established with
thrombolytic agents. Furthermore, the differential treatment effect in the setting of comparable ischemic insults implies that different modifiable biochemical processes may be present during temporary but not permanent focal
ischemia, thus providing indirect evidence for
reperfusion injury.