Pregnancy in transplanted mouse uterus after long-term cold ischaemic preservation

BACKGROUND: The aim of this study was to evaluate the viability of the transplanted murine uterus after cold ischaemic preservation. METHODS: Uteri of mice (6-8 weeks old) were isolated and kept at 4degreesC in vitro for 24 or 48 h in 0.154 mol/l NaCl or University of Wisconsin (UW) solution. Viability was evaluated by assessment of morphology and contractility in vitro. Furthermore, uteri were transplanted by vascular anastomoses to syngeneic recipients after 24 or 48 h cold ischaemic preservation in UW solution and morphology, blood flow and capacity to implant transferred blastocysts were assessed 2 weeks later. RESULTS: Uteri that had been preserved for 24 h exhibited normal morphology but after 48 h preservation minimal degenerative changes were seen. Spontaneous contractions occurred in uteri after 24 h as well as 48 h cold ischaemic preservation and prostaglandin F-2alpha-stimulated responses were preserved. Blood flow and morphology were normal 2 weeks after transplantation in uteri preserved for 24 h, while grafts preserved for 48 h had a decreased blood flow and morphology showed total necrosis of the transplants. Transplanted uteri that had been preserved for 24 h developed pregnancies (in five out of six animals) after embryo transfer, with offspring showing normal weight and growth trajectory. CONCLUSIONS: This study shows for the first time that the mouse uterus tolerates cold ischaemic preservation and that pregnancies can be carried in transplanted uteri that have been preserved for 24 h.