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 so metimes occur due to sudden-onset disease or accident. We previously showed that mice can be rescued by trans plantation of ovaries taken up to 2 h af ter death from dead mice remaining at conditions of constant temperature (2 2 +/-2 degreesC) and humidity (55%+/-5%). To extend the flexibility of tran splantation, we assessed whether it is possible to cryopreserve ovaries tak en from dead mice within 2 h after death. Fertile transgenic mice used as d onors were euthanized by cervical dislocation and left for 2 h after death. The cryopreservation was based on Sztein's method with a controlled-rate f reezer 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-f ertile males. Polymerase chain reaction (PCR) analysis confirmed that the p rogeny carried the transgene. We show here that by using both of the descri bed methods, it is possible to cryopreserve the ovaries taken from dead mic e within 2 h after death and that the mice into which the cryopreserved ova ries are transplanted are fertile.