LONG-TERM EFFECTS OF EXPOSURE TO METHYLNITROSOUREA ON BLASTOCYSTS FOLLOWING TRANSFER TO SURROGATE FEMALE MICE

  • 1 January 1984
    • journal article
    • research article
    • Vol. 44  (7) , 2785-2789
Abstract
The effect of in vitro preimplantation exposure of mouse embryos to N-methyl-N-nitrosourea (MNU) on development subsequent to embryo transfer into pseudopregnant surrogate mothers was investigated. The offspring developed from mouse blastocysts exposed to MNU or to solvent were examined carefully for 1 yr after birth and then examined with X-rays and complete autopsies. Metaphase chromosomes were examined in some of these animals. Exposure to MNU at the morula stage did not affect progression to the blastocyst stage in vitro; however, exposure at the blastocyst stage resulted in a profound reduction in the live birth rate. Offspring developed from blastocysts exposed to MNU in vitro were found to have a 3-fold higher crude mortality rate than offspring developed from blastocysts exposed to solvent. There were no gross dysmorphogenic effects of exposure, nor were any major histologic abnormalities associated with MNU exposure. No chromosomal abnormalities were discovered in either surviving group of off spring. [MNU is a mutagen and carcinogen.].