Effects of global cerebral ischemia in the pregnant rat.

Abstract

Stroke during pregnancy is an emerging concern. Although females undergo many physiological, endocrine, and neurological alterations during pregnancy, the consequences of such changes on outcome after stroke are unclear. It is predicted that increases in steroid hormones observed during pregnancy may confer protective effects against the neurological and pathological sequelae of stroke. We therefore investigated behavioral and histological consequences of a global cerebral ischemia (2-vessel occlusion; 2VO), and how these outcomes correlated with pregnancy-related changes in hormones in Sprague-Dawley rats. After the 2VO, pregnant rats exhibited poorer memory in a contextual fear conditioning test of learning and memory than sham-treated controls, whereas nonpregnant rats did not. They also showed enhanced CA1 hippocampal neuronal injury. This susceptibility to damage is despite significant pregnancy-associated hypothermia and is probably not associated with alterations in 17beta-estradiol or corticosterone levels. These findings are the first to show enhanced neuronal damage in pregnant animals after global cerebral ischemia. They also suggest that the mechanism may be independent of changes in estrogen, corticosterone, and body temperature.