Sealed culture system for supporting mouse preimplantation embryo development in vitro

This study investigated the possibility of a sealed culture system in polymerase chain reaction (PCR) tubes to maintain embryo development. The embryo density that could support the development of 2-cell stage mouse embryos to the hatching stage was determined. At an embryo density of 1:2 (100 embryos cultured in 200μL CZB medium that had been pretreated with a reference gas containing 5% O2), the developmental rate was higher and fewer embryos exhibited reactive oxygen species- or hypoxia-induced injury compared with other sealed culture groups. Expression of growth factors (insulin-like growth factor (IGF) 1, IGF2, epidermal growth factor and transforming growth factor-α) and their receptors was evaluated, with similar expression patterns seen for embryos in sealed culture (5% O2, embryo density of 1:2) compared with the control group (embryos cultured in microdrops and placed in a 37°C, 5% CO2 water-jacketed incubator; P>0.05). After transfer of blastocysts generated by the sealed culture into recipients, there were no obvious differences in the rate of normal live pups births between the sealed culture and control groups (P>0.05). Thus, the sealed embryo culture system in PCR tubes is feasible for use in situations which cannot use a traditional incubator, such as in space and during the transport of embryos.