Rescue of a transgenic mouse line by transplantation of a frozen-thawed ovary obtained postmortem.

During the course of breeding valuable mutant or transgenic mice, deaths sometimes occur due to sudden-onset disease or accident. We previously showed that mice can be rescued by transplantation of ovaries taken up to 2 h after death from dead mice remaining at conditions of constant temperature (22 +/- 2 degrees C) and humidity (55% +/- 5%). To extend the flexibility of transplantation, we assessed whether it is possible to cryopreserve ovaries taken from dead mice within 2 h after death. Fertile transgenic mice used as donors were euthanized by cervical dislocation and left for 2 h after death. The cryopreservation was based on Sztein's method with a controlled-rate freezer or on Rall and Fahy's method without a controlled-rate freezer. The recipient mice were nontransgenic littermates of the donor mice, and after transplantation of the frozen-thawed ovaries, they were mated with proven-fertile males. Polymerase chain reaction (PCR) analysis confirmed that the progeny carried the transgene. We show here that by using both of the described methods, it is possible to cryopreserve the ovaries taken from dead mice within 2 h after death and that the mice into which the cryopreserved ovaries are transplanted are fertile.