Cryopreservation

Transgenesis has increased the number of mouse lines to tenfold the actual number of lines. The maintenance costs of these animals has thus increased enormously. Most of these lines have been generated for a particular purpose and may become unnecessary when the research evolves. However, these lines may still be useful for other research. Maintaining these lines represents a significant cost that can interfere with the progression of other research. The best solution to this problem is to cryopreserve these lines and to store their embryos or sperm at -196 ° C in liquid nitrogen (LN2), avoiding thus to keep them as "metabolizing" animals.

Besides the fact that cryopreservation of embryos allows to "resurrect" a line as needed, it can also save (make a back-up) lines that do not exist elsewhere and thereby allow any sharing with an outside laboratory that manifest the need. It also allows exchanges of animals without causing them to suffer the stress of transport, while reducing health risks. Cryopreservation of mouse lines is therefore fully in line with the rule of the “3R” (Reduction, Refinement, Replacement) allowing to reduce the number of animals housed. Cryopreservation has also the advantage to reduce the genetic drift.