Estradiol: A protective factor in the adult brain

Clinical studies suggest that estradiol acts as a protective factor in the adult brain. Postmenopausal women suffer from an increased risk of brain in jury associated with neurodegenerative diseases such as Alzheimer's disease , and estrogen replacement therapy appears to decrease the risk and severit y of this neurodegenerative condition. Studies using animal models show tha t estradiol exerts similar effects in rodents and can enhance cell survival . Therefore, we designed experiments to determine whether estradiol treatme nt can decrease brain injury induced by an experimental model of ischemia, Our experiments used a permanent middle cerebral artery occlusion model and physiological levels of estradiol replacement therapy. The results demonst rate that estradiol exerts profound protective effects against ischemic bra in injury induced by cerebral artery occlusion and that this protective act ion correlates with changes in the level of gene expression of estradiol re ceptors and members of the Bcl-2 family. These data suggest that estrogen r eplacement therapy may provide important protection against age- and diseas e-related degenerative processes in the brain.