5 μL/h, 14-day release; Alzet, CA, USA) implanted between their scapulae containing either placebo (20% β-cyclodextrin) or 17β-estradiol (0.0167 mg E2 in 20%

β-cyclodextrin) to mimic physiological E2 levels produced during Diestrus I (10–15 pg/mL serum).16 As such, STED rats modeled surgical menopause with immediate E2 therapy and LTED modeled surgical menopause with delayed E2 therapy. One week after continuous treatment, GCI was performed using 4-vessel occlusion as described previously.32, 33 and 34 Briefly, the day before GCI, animals were anesthetized using intraperitoneal chloral hydrate (350 mg/kg) or intraperitoneal ketamine/xylazine (60 mg/kg and 8 mg/kg, respectively), and both vertebral arteries (VA) were permanently occluded at the level of Venetoclax solubility dmso the alar foramina via electrocauterization. Bleomycin Immediately following bilateral VA

occlusion, both common carotid arteries (CCA) were carefully isolated and loosely ligated with suture thread without interrupting blood flow. After a 24-h recovery period, animals were re-anesthetized with light isoflurane (1%–4%), and the bilateral CCA were occluded with hemostatic clips to induce 10 min of complete forebrain ischemia. Animals which lost their righting reflex within 30 s and whose pupils were dilated and unresponsive to light during cerebral ischemia were selected for the experiments. After 10 min, the clips were removed, and reperfusion was confirmed before the wound was sutured. During GCI, rectal temperature was maintained at 36.5 °C–37.5 °C with a thermal blanket. Sham animals did not receive pumps and underwent identical GCI surgical procedures except that the CCA were simply exposed but not occluded. For brain harvesting, animals were deeply anesthetized with isoflurane and transcardially perfused with 0.9% saline at 3 h or 24 h post ischemia-reperfusion, followed by fixation with cold 4% paraformaldehyde in 0.1 mol/L phosphate buffer (PB). Brains were post-fixed in the same fixative overnight at 4 °C and cryoprotected with 30% sucrose in 0.1 mol/L PB, pH 7.4 for 24–36 h. Coronal sections (25 μm) CYTH4 were collected throughout the entire dorsal hippocampus (∼2.5–4.5 mm

posterior from Bregma, ∼100 sections per brain) for each animal. For DAB staining, sections were incubated with 10% normal horse serum in phosphate-buffered saline (PBS) containing 0.1% Triton X-100 and 0.3% H2O2 for 1 h at room temperature to block nonspecific surfaces. Sections were then incubated with a single primary antibody: anti-PHF1 (1:1000, gift from Peter Davies) or anti-Aβ (1:100, MAB8768; Millipore, Billerica, MA, USA) overnight at 4 °C in PBS containing 0.1% Triton-X100 and 1% horse serum. Afterward, sections were washed with PBS containing 0.1% Triton-X100, followed by incubation with secondary biotinylated horse anti-rabbit/anti-mouse antibodies (1:500, Vector Laboratories, Inc., Burlingame, CA, USA) in the same buffer for 1 h at room temperature.