Does embryo vitrification affect the mice offsprings’ growth, development and the nervous system?

Abstract

This study focused on the effect of embryo vitrification on the growth, development and the nervous system of the offsprings. Comparative and controlled study. Mice were used as model animals, we designed three groups including natural pregnancy-born mice (control group), conventional IVF-ET pregnancy-born mice (IVF group), and embryonic vitrification-born mice (frozen group). The growth and development indicators and neurodevelopment indexes of offsprings were compared among the above groups; two-dimensional protein electrophoresis, mass spectrometry, and Western Blotting were used to determine the changes in brain tissues of the mice. Brain tissue ultrastructures of the offsprings were observed by immunohistochemical and electron microscopy. Physiological indicators such as physical strength were compared; the neural development indicators such as the intelligence, learning ability and memory were also compared through the Morris water maze test. 1. There was no significant difference in the pregnancy rate between the fresh transplantation group and the vitrification group (48.89% Vs 51.22%, P>0.05). 2. The weights of the offsprings in the vitrification group were higher than that in the conventional IVF group and the natural conception group (1.98±0.21 Vs 1.95±0.22, P<0.05). There was no significant difference in offspring weights between the conventional IVF group and the natural conception group (1.95±0.22 Vs 1.96±1.89, P> 0.05).3. Two-dimensional differentially expressed proteins in brain tissue were searched by two-dimensional protein electrophoresis, protein profiling, and Western blotting. Bioinformatics analysis revealed that most protein expression differences did not cause functional changes.4. Through immunohistochemistry and electron microscopy, it was found that vitrified frozen embryos had no obvious damage to the brain tissue ultrastructures. 5. Vitrification has not affected the structure of brain tissue in the study of mouse embryos through immunohistochemical and electron microscopy.6. Time to reach the platform,latency,the total distance and the frequency of crossing the former platform were similar among the three groups.(see the Table). The weights of the offsprings born through embryo vitrification were increased, while fertility, learning and memory ability were not changed. The technique of embryo vitrification has no significant effect on brain protein expression and tissue ultrastructures.The vitrification technique commonly used in clinic has little effect on the offsprings.Tabled 1The result of the Morris water maze testGroupsTime to reach the platform（s）latency（s）the total distance（cm）the frequency of crossing the former platform（times）frozen group13.04±1.8723.45±1.56212.74±19.381.88±0.71IVF group15.34±1.4820.67±1.79209.34±14.742.28±0.68control group13.46±1.7521.86±1.21218.53±12.471.97±0.46P value<0.05<0.05<0.05<0.05 Open table in a new tab