Pregnancy by tubal insemination in rabbits using sperm cells capacitated in vitro.

It has been suggested that the mechanical interference involved in inserting a tube into the oviduct before ovulation, during tubal insemination, may impair the capacity of the tubal fimbriae to pick up ovulated eggs. When fresh sperm cells are used, the semen has to be injected into the oviduct before ovulation to allow time for sperm capacitation. In the present study in rabbits, sperm cells capacitated by pre-incubation in vitro were injected into the oviducts through the tubal fimbriae after ovulation. Two of the six rabbits inseminated became pregnant and gave birth to one and three offspring, respectively. Injecting capacitated sperm cells after ovulation may avoid the potential problems posed by mechanical damage of the tubal fimbriae.