BIRTH OF LIVE MICE DERIVED BY IN-VITRO FERTILIZATION WITH SPERMATOZOARETRIEVED UP TO 24 HOURS AFTER DEATH

The objective of this study was to determine the viability and fertili ty of mouse spermatozoa obtained at various postmortem intervals. Male mice were euthanized, and the bodies were kept at similar to 22 degre es C for up to 24 hr. The epididymides were removed and spermatozoa we re allowed to swim out into Minimum Essential Medium supplemented with bovine serum albumin. Motility of spermatozoa retrieved within 12 hr postmortem was similar to 60%, whereas motility of those obtained 6 to 12 hr later decreased significantly (P < 0.05). There appeared to be no differences in the percentages of spermatozoa with intact plasma an d acrosomal membranes regardless of the time after death. After in vit ro fertilization of oocytes with spermatozoa collected immediately aft er death or at 6, 12, 18, or 24 hr postmortem, the cleavage rates were 81%, 70%, 64%, 34%, and 19%, respectively. Once oocytes were fertiliz ed, more than 65% developed into morulae/blastocysts. Transfer of a to tal of 166 embryos produced in vitro with postmortem spermatozoa resul ted in the birth of 44 live pups (26.5%). Of these 44, 3 live mice wer e derived by transfer of 11 embryos (27.3%) produced with 24-hr postmo rtem spermatozoa. Histological examination of the testes and epididymi des obtained at various postmortem intervals revealed that degenerativ e changes of the testes occurred within 6 hr, whereas those of the epi didymides were less obvious until 6 hr later. These changes included p yknosis, release of intracellular contents, and disruption of intercel lular bridges of the germ cells. This study has demonstrated that sper matozoa recovered from a dead animal as long as 24 hr after death can be used to fertilize oocytes, and that the resulting zygotes can devel op into live young. (C) 1998 Wiley-Liss, Inc.