De-tensioning of collagen fibers optimizes endometrial receptivity and improves the rate of embryo implantation

Successful embryo implantation is associated with intensive endometrium matrix remodeling, in which fibrillar collagens and matrix metalloproteinases play a key role. Here we report that topical treatment with a single dose of human collagenase-1 improves the rate of embryo implantation in murine models regardless of genetic background. Collagenase-1 treatment reduces endometrial collagen-fiber tension affecting their aligned configuration while preserving the overall integrity of the uterine tissue. The collagenase treatment causes enhanced local vascular permeability and creates an inflammatory-like environment, all of which are necessary for successful embryo implantation. We show that this specific treatment rescued heat stress and embryo transfer induced embryo failure in mice. Our findings highlight the clinical feasibility to improve endometrial receptivity for embryo implantation. This treatment approach may be used to improve livestock breeding and for assisted human reproduction medical treatments. ### Competing Interest Statement The authors have declared no competing interest.