Figure 1.

E₂ attenuates apoptotic neuronal cell death in hippocampal CA1 region at 7 d after global cerebral ischemia in an estrogen receptor-dependent manner. A, Hippocampal sections from sham, Pla-treated, E₂-treated, and E₂ plus the estrogen receptor antagonist ICI182,780-treated (ICI) female ovariectomized animals were double stained with NeuN (red) and Fluoro-Jade B (green) or separately stained with TUNEL (red, right column). Cells that stained positively for NeuN staining and negatively for Fluoro-Jade B staining were identified as surviving neurons. In contrast, NeuN/Fluoro-Jade B double-stained (yellow) cells represent CA1 pyramidal neurons undergoing degeneration. B, Quantitative summary of data (means ± SE; n = 6–8 animals per group) shows the number of surviving neurons (a) or TUNEL-positive cells (b) per 250 μm length of medial CA1. Scale bar, 50 μm. Magnification, 40×. *p < 0.01 versus Pla group; ^†p < 0.05 versus E₂ treatment group.