Potential role of toll-like receptor 3 in a murine model of polyinosinic-polycytidylic acid-induced embryo resorption

ObjectiveTo investigate the potential role that toll-like receptor 3 (TLR3) may play in a murine model of polyinosinic-polycytidylic acid (polyIC)-induced embryo resorption.DesignAn animal model–based study on induced embryo resorption.SettingUniversity animal laboratory.Animal(s)Pathogen-free animals housed under barrier conditions and monitored for health status. Pregnant BALB/c mouse mated by C57BL/6 male was used as a model of allogeneic gestation.Intervention(s)The administration of polyIC was performed to establish a murine model of induced embryo resorption, with or without TLR3 blocking by multiple injection of mAb against this receptor.Main Outcome Measure(s)Flow cytometric analysis was performed to detect the percentage of CD45+DX5+ and DX5+CD69+ cell subsets, with the DX5 antigen used as a common natural killer (NK) cell marker, and CD69 as a marker for activated NK cells, respectively.Result(s)In the allogeneic mating model, BALB/c×C57BL/6, both the CD45+DX5+ and DX5+CD69+ cell percentages were significantly elevated upon polyIC stimulation at the absence of anti-TLR3 administration but were kept unchanged if the female mice were pretreated with anti-TLR3 monoclonal antibody. Accordingly, the resorption rate of embryos was boosted by polyIC administration, but this effect could be abrogated by pretreatment of anti-TLR3 mAb.Conclusion(s)The engagement of polyIC with TLR3 may be critical to the activation of NK cells infiltrated at the feto-maternal interface, subsequently resulting in an increase in embryo resorption.