Gonadectomy and Sham Surgery in Rats

On P21, rats from separate breeding pairs were weaned from their mothers and pair housed by sex. On P28, males and females were removed from the vivarium for surgery. Using 2.5% isoflurane gas anesthesia, each gonadectomy, and sham surgery was completed with an average duration of 25 minutes from induction to completion. Both ovariectomies and orchiectomies were performed with a ventral incision in the lower abdominal area through the skin and then another through the muscle wall, after which testes or ovaries were located on each side of the rat, ligated with absorbable surgical thread, and removed. The muscle incision was closed using absorbable sutures, and the skin incision was closed using both sutures and Vetbond surgical glue. Animals were then placed in separate cages until they fully recovered from anesthesia before being placed back with their littermate. Identical skin and abdominal incisions were made on sham animals, but the gonads remained intact; the duration of isoflurane exposure was equal to that of castrated animals. Rats were returned to the vivarium after the restoration of the righting reflex. Following surgery, all rats were administered Carprofen (5 mg/kg) subcutaneously for two consecutive days and monitored for seven days. Post-surgery sham and gonadectomized rats were separately pair-housed.