Caesarean sectioning and cross-fostering of mouse

Introduction to cesarean section procedure and its applications in deriving pathogen-free mouse strains. The procedure is typically performed 18 days after vaginal plug detection.

Kill the pregnant mother by cervical dislocation and position the mouse on its back. Disinfect the abdominal area with 75% ethanol to maintain sterility.

Make a midline incision through the skin using surgical scissors, then carefully lift and incise the muscular layer while avoiding damage to internal organs.

Remove the uterus and place it on a sterile drape. Carefully cut through the uterine wall to expose the embryos within their fetal membranes.

Dissect the pups from yolk sac and amnion, cut the umbilical cord, and transfer to clean paper towel. Gently roll pups over the towel to stimulate breathing and clean amniotic fluid.

Place pups on moist tissues on a 37°C warming plate to maintain body temperature. Monitor until pups become pink and move vigorously with squeaking response to tail pinching.

Rub cesarean-derived pups with bedding from the foster mother and mix them with her natural litter. Remove some original pups to balance the litter size for successful nursing.

Check for successful adoption by the foster mother no earlier than 24 hours after transfer to confirm pup acceptance and welfare.