Low, physiological levels of E2 exert neuroprotection. E2 protects against neuronal death in a stroke model in which the middle cerebral artery is permanently occluded. A: C57BL/6 J mice were ovariectomized and immediately implanted with capsules containing either oil or E2 for 1 week. Subsequently, animals underwent experimental ischemia by middle cerebral artery occlusion and were killed 24 h after the onset of injury. Infarct volumes were measured using TTC staining in oil- or E2-treated mice. B–D: E2 treatment significantly reduced the total infarct volume (B, P < 0.02) and the extent of injury in both the cortex (C, P < 0.05) and striatum (D, P < 0.03). Data represent the mean ± SEM of 8–11 animals per group. Figure reprinted with permission from [85].