Effects of Exposure to Nitrous Oxide After Fertilization on Embryo in Vitro and in Vivo Development in Mice / 대한마취과학회지

ABSTRACT

BACKGROUND: Nitrous oxide exposure for long periods during gestation causes the increased fetal wastage, growth retardation, morphological abnormalities in rodents. Most studies have explained deleterious effects of nitrous oxide on postimplantation embryo development. The aim of this study was to evaluate the effects of nitrous oxide on embryo after the fertilization in superovulated BALB/c mice. METHODS: Pregnant mice were exposed to 70% nitrous oxide in oxygen for 6, 12 and 24 hours on the day of gestation, and 2-cell stage embryos were cultured to blastocyst. Reproductive data were determined at cesarean section on 16th day of gestation based on embryonic developmental failure in vitro by 24 hours nitrous oxide. The protective effects of folinic acid or methionine against inhibition of 2-cell embryo development were also evaluated. RESULTS: Blastocyst development was significantly lower in 12 and 24 hours nitrous oxide group than in the control and 6 hours nitrous oxide group. The pregnancy rate and the mean number of implantations were significantly lower in 24 hours nitrous oxide group than in the control. No significant differences in percentage of the living fetus, the dead fetus, the resorption per implantation, the mean fetal weight and the crown-rump length were observed between nitrous oxide group and control group. There was no significant difference between the nitrous oxide group and the nitrous exposed group receiving methionine and folinic acid. CONCLUSIONS: The exposure to high concentration of nitrous oxide for a long time after the fertilization in mice may be possibility of the early abortion of embryos, whereas there is not any influence on fetus after the implantation.