Splenectomy Does Not Improve Long-Term Outcome after Stroke

Abstract

Background and Purpose - Immune responses to brain antigens after stroke contribute to poor outcome. We hypothesized that splenectomy would lessen the development of such responses and improve outcome. Methods - Male Lewis rats (275-350 g) underwent 2-hour middle cerebral artery occlusion immediately after splenectomy or sham splenectomy. Animals were survived to 4 weeks (672 hrs), and immune responses to myelin basic protein determined at euthanasia. Infarct volume was determined in a subset of animals euthanized at 72 hours. Behavioral outcomes were assessed to 672 hours. Results - Splenectomy was associated with worse neurological scores early after stroke, but infarct size at 72 hours was similar in both groups. Behavioral outcomes and immune responses to myelin basic protein were also similar among splenectomized and sham-operated animals 672 hours after middle cerebral artery occlusion. Conclusions - Splenectomy did not alter the immune responses to brain antigens or improve outcome after stroke. Differences between this study and other studies of splenectomy and stroke are examined.