Implantation of Microinjected Eggs

Microinjected eggs are normally incubated overnight in Ml6 microdrop culture at 37�C in CO₂ until 1400 h. By this time the eggs will have developed as far as the two-cell stage. The eggs are then implanted into surrogate mothers. As the membrane covering the oviduct of the rat is much tougher than the mouse, we normally cut it with a very fine pair of scissors rather than tearing it. For a female rat that had been successfully induced into pseudopregnancy, the infundibulum will be swollen and the opening of the infundibulum can be clearly seen under the 10–20X magnification of the dissecting microscope.