The significance of light chronodestruction in the development of the embryotoxic effect in the experiment

   Objective. To assess the significance of light chronodestruction in the development of the embryotoxic effect in the experiment.   Materials and methods. The experiment was conducted on 60 female rats of the Wistar line. To assess the significance of chronodestruction in the development of embryotoxic effect, the uterus was isolated in the experiment, in which the number of implantation sites, the total number of embryos, the number of live and dead embryos, and the number of resorptions were estimated. The number of corpus luteum in the harvested ovaries was estimated. In addition, the mean embryo weight (g) and mean craniocaudal size (mm) were recorded. Indicators of embryotoxic effects of light deprivation were determined by pre- and post-implantation death, which was calculated in accordance with methodological recommendations.   Results. Exposure to light deprivation reduces the number of implantation sites as of 7th, 14th and 21st days by 1,5-1,8 times, the total number of embryos by 1,6-1,8 times, the number of living embryos by 2,2-9 times and increases the number of dead embryos as of 14th and 21st days by 4-5,5 times, the number of resorptions – 1,6-11 times. The average craniocaudal size (mm) of embryos in experimental animals was recorded below control values by 1,5 times, 1,3 and 3,7 times by 7th, 14th, 21st days respectively. In females exposed to light deprivation, there was a significant increase in pre-implantation mortality by 35-41,8 times and post-implantation mortality by 7,2-20,4 times compared to the control.   Conclusion. Light deprivation may have a negative effect on pregnancy and fetal development in female rats, which is confirmed by an increase in pre- and post-implantation mortality.