Embryotechnology laboratory

In the interests of both animal welfare and the reproducibility of experiments, it is essential to maintain a defined health status (specified pathogen-free; SPF) in our animal facilities. The method of embryo transfer is used to import new mouse strains into the clean animal breeding area. Embryo and sperm freezing can also be used to cryopreserve mouse lines that are temporarily not required in order to limit the number of animals bred to the absolute minimum necessary. Frozen material is also ideally suited for the worldwide shipment of mouse lines, so that in many cases the shipment of live animals can be dispensed with in the interests of animal welfare. The DRFZ maintains a modern embryo technology laboratory for these technologies at its Berlin Marienfelde site.

The following services are offered:

Embryo transfer

To ensure a defined health status of the animals in the SPF facility, new mouse strains are imported via embryo transfer. Two-cell embryos produced via in-vitro fertilisation (IVF) are first washed intensively to remove all pathogens. These are then implanted into sham pregnant females and the resulting offspring are born within the SPF facility.

Cryopreservation of sperm and embryos

Mouse strains that are temporarily not required can be stored as sperm or embryos in liquid nitrogen. Frozen material is also ideally suited for the worldwide shipment of mouse lines, so that in many cases the shipment of live animals can be dispensed with.

In-vitro fertilisation (IVF)

Artificial insemination is a very efficient method for creating embryos. It is also used to reconstitute mouse strains from frozen sperm.

Fig. 1: Workflow of services offered by the Embryo Technology Laboratory. In vitro fertilization (IVF) is used to generate large numbers of 2-cell embryos. These embryos as well as sperm from transgenic mice can be cryoconserved in liquid nitrogen. To remove any pathogens, embryos are washed extensively before transfer into pseudo-pregnant foster mice inside the SPF facility.

Fig. 2: Washing of embryos. The fertilized oocyte is protected by the zona pellucida which is impermeable for pathogens. Residual sperm is still sticking to the zona.

Fig. 3: Developmental stages of mouse embryos. a) Sperm and oocytes (hidden in the cumulus cells) 5 min after IVF. b) 45 min after IVF, sperm almost completely dissolved the cumulus cells. c) 2-cell embryos. d) 4- and 8-cell embryos. e) Morula stage. f) Blastocysts.

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Embryotechnology laboratory

Modern technology for efficient breeding management and animal welfare