Neuroprotective effects of combined estrogen and hypothermia after transient forebrain ischemia in rats

点击翻译按钮获取中文摘要

We examined whether combined treatment with estrogen and hypothermia reduces brain injury after transient forebrain ischemia in rats compared with either treatment alone.Methods : Male Sprague. Dawley rats were anesthetized with halothane and nitrous oxide in oxygen. Five groups were tested (n=8 each group): group C (vehicle 5 mg/kg, temporal muscle temperature 37.5℃); group E (17β-estradiol 200 μg/kg, 37.5℃); group H (vehicle 5 mg/kg, 35.0℃); group EH (17β-estradiol 200 μg/kg, 35.0℃); and group S (sham surgery, 37.5℃). In the groups H and EH, the temporal muscle temperature was reduced to 35℃ immediately after ischemia and maintained for 1 hour. Estrogen or vehicle was administered intravenously immediately after ischemia. Cerebral ischemia was produced by bilateral carotid artery occlusion with hemorrhagic hypotension (mean arterial pressure 40mmHg) for 10 min. Histopathology and neurologic deficit score were evaluated at 28 days after ischemia. Results : 28 days after ischemia, the numbers of intact neurons in the hippocampal CA1 subfield in the groups E (5±3/mm ; mean±SD), H (19±24/mm), EH (21±28/mm) were comparable with the group C(5±2/mm). The group S (132±22/mm)showed a significantly increased number of intact neurons compared with other four groups. There were no significant differences in neurologic deficit scores among five groups. Conclusion : A combination of estrogen and hypothermia did not provide greater neuroprotection compared with either treatment alone.