Endometrium procurement and transplantation restores fertility in rats

Research question: Can rat endometrium be successfully procured and transplanted, and can a similar method be used to procure human endometrium? Design: Rat endometrium was procured using an endometrium stripping method and transplanted into female Sprague-Dawley rats. Macroscopic and histological changes, endometrial receptivity-related protein concentrations and fertility were assessed. Additionally, a preliminary experiment was conducted to procure human endometrium using a similar method. Results: Endometrium was successfully procured from both rats and humans, which contained intact endometrium and parts of the adjacent inner annulus myometrium. Endometrium auto-transplantation was conducted in rats and the procedure lasted a total of 41.3 +/- 5.7 min with a mean blood loss of 0.09 +/- 0.04 g. The transplanted endometrium survived well, but a fibrotic zone formed between the transplant and recipient tissue. Compared with sham rats, those with endometrium transplantation had similar endometrial thickness and endometrial gland numbers but reduced vascular density at 8 weeks after surgery. Endometrium transplantation also retained expression of the endometrial receptivity-related proteins leukaemia inhibitory factor and vascular endothelial growth factor. In contrast to non-pregnancy in the stripped horn, a mean of 5.0 +/- 2.7 fetuses developed in the transplanted horn, and full-term live fetuses were conceived in the horns with transplanted endometrium. Conclusions: Endometrium procurement by stripping method can obtain an intact and functional endometrium, and endometrium transplantation can reconstruct the uterine cavity and restore fertility in rats.