Animals and Tissue Collection
At birth (Day 0), crossbred gilts were assigned to remain intact (n = 30) or to be ovariectomized (OVX, n = 25) on Day 0. Animals in each treatment group were then assigned to be hysterectomized (n = 5 gilts per day) under general anesthesia on either Day 0 (intact only), 15, 30, 60, 90, or 120. Procedures were approved by the Auburn University Institutional Animal Care and Use Committee and were in accordance with the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. flovent inhaler
Each uterus was trimmed free of supportive connective tissues; oviducts and ovaries (intact only) were removed, and the uterus was separated from the cervix at the level of the internal cervical os. Uterine wet weights were obtained using an analytical balance. A cross section (approximately 1 cm in length) from the middle of one uterine horn was fixed immediately in 4% paraformaldehyde, embedded in Paraplast Plus (Sherwood Medical, St. Louis, MO), and sectioned at 5-7 |j,m. The remainder of the uterus was snap-frozen in liquid nitrogen and stored at -80°C. A segment of small intestine from one pig was obtained at the time of hysterectomy, fixed in 4% paraformaldehyde, embedded, and processed for use as a negative control tissue for ER immunohistochemistry. After embedding, tissues for histological analyses were processed as described previously, then stained with hematoxylin and counterstained with eosin. Procedures for histological measurements were as described by Spencer et al.. Tissue sections were mounted on poly-L-lysine (0.1% v:v; Sigma Chemical Co., St. Louis, MO)-coated glass slides.