Estrous Cycle Assessment in Female Mice

Estrous cycles were assessed at the same time every day during behavioral study performance day following published protocols [53 (link), 54 (link)]. Female mice were properly handled to minimize stress, by gently lifting the animal by the base of tail a plastic pipette filled with about 1 ml of PBS was placed on the tip of the vagina and flushed 5 times with same PBS to allow proper collection of samples for vaginal cytology. Sample was then smeared on appropriate labeled microscope slides and after 1 h of drying time, a crystal violet (0.1%) staining was performed on slides. After drying, the slides were observed under a light microscope to visualize cells. Images were obtained using NIS Elements imaging software version 4.0.