Hromosome Abnormalities and Viability of Vitrified Eight-Cell Mouse Embryos At Presence of Two Different Cryoprotectants At Different Storage Durations

Objective: experiments were conducted to find the differences between post-thaw viabilityandchromosomeaberrationsineight-cellmouseembryosatpresenceofdimethylsulfoxide(dmso) and 1, 2-propanediol (proh) as croprotectants in different storage durations.materials and methods: in this case-control study, a total number of 720 mouse embryosfromabout250nmrimicewerevitrifiedwith30%prohordmso;eachdilutedwithasolutioncontaining30%ficolplus0.5msucrose.embryoswereexposedtothesolutionsfor0.5minuteat25?cfollowedbycoolinginliquidnitrogen,thenafterappropriatestorageduration,theywererapidlywarmed.besides,therewere100mouseembryosforeachcryoprotectantgroup(totally200embryos)ascontrol.embryosurvivalwasassessedbyinvitrodevelopment,andchromosomeabnormalitieswereanalyzedby giemsa staining.results: the proportion of mitotic abnormalities in proh/dmso vitrified embryos was sig-nificantly higher than unfrozen control group. this was confirmed also by a reduced viability of the embryos as judged by a culture at the blastocyst stage (p < 0.05 in all test groups).conclusion: it can be deduced that long term cryopreservation may result in chromosomalabnormalities and/or low viability.