Postgestational effects of macrophage migration inhibitory factor on embryonic implantation in mice

Objective: To investigate in vivo the effects of macrophage migration inhibitory factor (MIF) on endometrial receptivity and embryonic implantation. Design: A murine experimental model. Setting: Animal facilities at Research Center of Saint-Francois d'Assise Hospital. Animal(s): Ten-week-old B6C3F-1 female mice. Intervention(s): Intraperitoneal injections of recombinant mouse MIF or saline (control) the day after successful mating and during the peri-implantation period. Main Outcome Measure(s): Markers of uterine receptivity, including integrins and vascular endothelial growth factor (VEGF) were assessed using real-time polymerase chain reaction (PCR) and immunohistochemistry. Result(s): Quantitative real-time PCR and immunohistochemical analyses indicated that MIF induced a marked increase in alpha(v) (alpha v), beta3 (beta 3) integrin subunits and VEGF mRNA, and protein expression in the endometrium. The MIF(10 mu g/mL) significantly increased the number of von Willebrand factor-stained microvessels, and a significant correlation between VEGF expression and the number of von Willebrand factor-stained vessels was observed. Moreover, a tendency for an enhanced pregnancy rate (PR) in MIF-treated mice was seen compared with controls. Conclusion(S): These findings reveal that after gestation, MIF may play an important role in endometrial receptivity and embryonic implantation.