Reproduction Abstracts

Short-term effects of cryopreservation on embryo development, survival and after embryo transfer (ET), resulting pregnancy rate have been documented. However, long-term effects on offspring remain relatively unexplored.

Materials and methods: Using a mouse model, we investigated the effect of vitrification on blastocyst trophectoderm (TE) and inner cell mass (ICM) cell numbers by differential staining and postnatal growth and cardiovascular and metabolic health. Embryos were vitrified with equilibration (8 min) and vitrification media (1 min) followed by vitrification with liquid nitrogen. Embryos were warmed subsequently with thawing solutions (5 min) and cultured until blastocyst before ET. Offspring were weighed weekly, monitored for systolic blood pressure (SBP; weeks 9, 15, 21) and culled for organ allometry and serum collection (week 27).

Results and discussion: There is no significant differences (P<0.05) on survival rate between control (n=50) or vitrified (n=70) embryos. Vitrification reduced TE and ICM cells compared to controls but not significantly. Currently, offspring body weight between naturally-mated (controls; n=81), non-vitrified ET (IVC-ET; n=37) and vitrified ET (IVFr-ET; n=25) showed significant differences from week 3–8 to week 3–5 (P<0.05); respectively. Mean SBP showed no significant differences (P>0.05) in male and female offspring between control, IVC-ET and IVFr-ET treatments in week 9. We conclude that embryo vitrification may affect long-term growth of offspring into adulthood. Funding EU FP7 EpiHealth and MARA, Malaysia.