A new simple and reliable vitrification device based on Hollow Fiber Vitrification (HFV) method evaluated using IVP bovine embryos
Malenko, Galina PKornienko, Ekaterina VNesterov, Ivan IKosovsky, Gleb Yu
A new vitrification device based on hollow fiber vitrification (HFV) was constructed using a glass capillary, which lead to simplified construction process and increased practicality of the device. The hollow fiber was attached to heat-pulled tip of the glass capillary using forceps. A protective sheath fitted on the capillary provided protection for the cellulose triacetate hollow fiber with loaded embryos and allowed safe storage in liquid nitrogen for long periods of time (2-12 month), transfer between tanks with liquid nitrogen and transportation within these tanks. No embryos were lost in the process. The device was tested using seven-day-old and eight-day-old IVP bovine blastocysts and expanded blastocysts as a model. Obtained survival (90% at 24 h post warming) and hatching rates (62% at 72 h post warming) of day 7 blastocysts and expanded blastocysts were comparable to those gained using various vitrification carriers. Vitrified embryos did not show an increase in the number of cells with damaged membrane or a decrease in total cell number per embryos in comparison to their non-vitrified counterparts. Day 7 and 8 expanded blastocysts did not differ significantly in terms of survival at 24 (97.01 vs. 97.50%) and 48 h post warming (95.52 vs. 95%), but showed significantly higher survival and hatching rates than day 7 and 8 blastocysts. These results indicated that high and repeatable survival rates can be obtained by selection of IVP bovine embryos at the developmental stage of expanded blastocyst for HFV. Further modification of the method may be required to achieve high and stable results with different developmental stages of IVP bovine embryo. The vitrification device presented in the current article may contribute to wider application of HFV method in livestock production.(AU)
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