The effect of a novel cryoprotective agent, carboxylated ε-poly-l-lysine, on the developmental ability of re-vitrified mouse embryos at the pronuclear stage

PN embryos were vitrified with dimethyl sulfoxide (DMSO) and ethylene glycol (EG) as CPAs. After warming, some embryos were re-vitrified up to three times. The re-vitrification did not affect survival and in vitro developmental ability. PN embryos were also vitrified with COOH-PLL instead of DMSO up to three times. The embryos re-vitrified with COOH-PLL and EG also maintained high survival and developmental ability. However embryos vitrified with COOH-PLL and EG at three times significantly showed higher developmental ability (61.2 ± 3.1%) than those vitrified with DMSO and EG at three times (44.2 ± 2.7%) which was equivalent to that of fresh embryos (70.0 ± 3.6%). Taken together, our results show that re-vitrification of mouse PN embryos did not have a detrimental effect on the in vitro and in vivo development of the embryos. In addition, COOH-PLL is available as a CPA for vitrification of mouse PN embryos.