Development and characterization of an endometrial tissue culture model for study of early implantation events

Objective: To improve and characterize an endometrial tissue culture model. Design: Experimental study of the characteristics of mouse endometrial tissue cultured on amniotic membrane matrix. Setting: University research laboratory. Animal(s): Sexually mature female ICR mice. Intervention(s): Histologic examination of the cultured endometrial tissues. The attachment rates of the cultured tissues to implantation blastocysts under various conditions were determined. Main Outcome Measure(s): Morphometric analysis of the cultured tissues. Blastocyst attachment rate and expression of decidualization markers cylcooxygenase-2, connexin 43, and peroxisome proliferator-activated receptor δ. Result(s): Endometrial tissues could be grown on amniotic membrane matrix for 3 days with morphometric parameters similar to those in the in vivo pseudopregnant control. The cultured tissues responded to the surrounding steroid environment. Morphometric assessment indicated that medium containing 63.5 nmol/L P and 0.9 nmol/L E₂ provided the best support. The condition allowed attachment of approximately 60% of the cocultured blastocysts. A small percentage of the attached blastocyst started to penetrate the luminal epithelium within 28 hours. The attachment rate was significantly reduced with prior treatment of the cultured endometrium with anti-leukemia inhibitory factor antibody. The attached blastocyst induced decidualization around the attachment site. Conclusion(s): The model is useful for the study on implantation in the mouse.