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 4 degrees C 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.

Heterotopic uterine transplantation by vascular anastomosis in the mouse.

A method of heterotopic uterine transplantation was developed in the mouse as a model system for studies of uterine function and transplant immunology of the uterus. The model involved transplantation of the right uterine horn and the cervix by vascular anastomosis to a donor animal with the intact native uterus remaining in situ. F1-hybrids of inbred C57BL/6 x CBA/ca (B6 CBAF1) mice of 6-8 weeks of age (n=42) were used. The specific pelvic vascular anatomy of these mice was first examined by intra-aortal injection of a two-component silicon-rubber curing agent. The surgery of the donor animal involved microsurgical isolation of the right uterine horn and the cervix, with preserved vascular supply from the aorta through the right uterine artery. After isolation of the uterine horn with vascular supply and venous drainage, including approximately 3 mm of the inferior vena cava and aorta, the organ was put on ice. The recipient animal was prepared by exposing and mobilizing the infrarenal part of the aorta and the vena cava. The grafted uterus was placed in the abdomen on the left side and the aorta and vena cava of the graft were anastomosed end-to-side to the aorta and vena cava of the recipient animal with 11-0 sutures. The total time for these procedures declined with time and was 125+/-4 min for the last 28 operations. Viability of the uterus was confirmed, several days later, by demonstrating a blood flow similar to that of the native uterus, and histology of the grafted uterus demonstrated normal morphology, including intact ultrastructure of the endothelial cells. The overall survival rate of the recipient animals increased with learning from approximately 40% in animals 1-21 to 71% in animals 22-42. The proportion of viable grafts, as judged by normal blood flow and histology among the surviving mice was 25% in animals 1-21 and 87% in animals 22-42. An undisturbed function of the transplanted uterus horn was finally demonstrated by its ability to implant inserted blastocysts and to carry pregnancy with fetal weight being similar to that of fetuses in the native uterus and controls. In conclusion, this is the first report of successful transplantation of the uterus with proven functionality in the mouse. The model should be useful for many aspects of research in uterine physiology and pathophysiology.

The antibody-neutralisation of PDGF, CSF-1, TGFb2,3, EGF and EGF-receptor in utero in pre-implantation mice.

The aim of this study was to determine whether specific growth factors, those shown to be involved using PCR and immunohistochemistry, are necessary for the in-vivo mechanisms of normal implantation in mice. The abdomen of pregnant female mice were opened surgically on day 4 to expose the uterine horns, which were microinjected with specific neutralising antibodies against PDGF, CSF-1, TGFb2,3, EGF and EGF-receptor. At autopsy on day 12, the numbers, positions and sizes of all implantation and resorption sites were recorded. Sham-operation controls were utilised to evaluate the implantation model. Normal female mice exhibited a mean of 6.24 implantation sites per uterine horn. Sham-operated mice exhibited a 30.8% reduction in implantation compared with normals, and saline-injected mice exhibited a 45.7% reduction. Antibody-injected horns were compared with horns injected with saline and horns injected with heat deactivated antibody. All neutralising antibodies tested resulted in significant reductions in the implantation rate and the size of the implantation site. These experiments confirm, in vivo, participation of the specific growth factors tested in the mechanisms of murine implantation, as alluded to previously by evidence from PCR in vitro stimulatory and immunohistochemical work.