Begin non-surgical embryo transfer in the CD1 mouse on day 6 by placing a 20 microliter drop of M2 medium onto the lid of a tissue culture dish. Use reflective lighting under a microscope and load 10 to 20 blast assists into the M2 medium drop with a standard embryo handling pipette. Secure the non-surgical embryo transfer device onto a P2 pipette set to 1.8 microliters and remove the protective catheter cover.
Press the plunger of the pipette to the first stop and lower the tip of the catheter into the medium before slowly pulling the embryos into the catheter tip of the device. Then remove the catheter from the medium. Next, set the pipette volume to 2.0 microliters to generate a small air bubble at the tip of the catheter.
Gently lay the pipette loaded with the embryos near the mouse cage. Place the recipient female on the wire rack cage top and hold the mouse in position by grasping near the base of the tail using the forefinger and the thumb then angle the tail upward while stabilizing the animal. Place a small speculum into the vagina and insert the transfer device catheter into the speculum through the cervix and into the uterus.
Once the device hub contacts the speculum dispense the embryos by pressing the pipette plunger to the first stop. Avoid the transfer of extra air into the uterine horn. Remove the device and speculum.
