Oil-Soluble Contrast Medium (OSCM) for Hysterosalpingography Modulates Dendritic Cell and Regulatory T Cell Profiles in the Peritoneal Cavity: A Possible Mechanism by Which OSCM Enhances Fertility

Hysterosalpingography (HSG) with oil-soluble contrast medium (OSCM) is known to enhance fertility, although the mechanism is unclear. OSCM remains in the peritoneal cavity for several months after HSG. We hypothesized that OSCM that remains in the peritoneal cavity modulates dendritic cell (DC) and regulatory T cell (Treg) profiles and contributes to enhanced fertility. We characterized the profiles of DCs and Tregs in the peritoneal fluid from women who had undergone HSG. In vitro and in vivo effects of OSCM on monocyte-derived DCs and mouse peritoneal T cells were also evaluated. In comparison with women who have never experienced HSG, samples from women who had undergone HSG contained myeloid DCs with greater complexity and maturation, as well as had a marginally greater proportion of Tregs in their peritoneal fluid. OSCM is incorporated by monocyte-derived DCs, which causes their maturation and contributes to the increase in Treg proportions. Samples from OSCM-injected mice contained greater proportions of Tregs in comparison with controls. These studies demonstrate that OSCM modulates T cell profiles that are compatible with the condition observed in women who have undergone HSG. This study demonstrates that exogenous lipids administered to the peritoneal cavity are incorporated by DCs and that they significantly alter the immune environment in the peritoneal cavity. This immunological impact may contribute to enhanced fertility and the development of alternative therapeutic strategies for managing other pathological conditions associated with immunological abnormalities in the peritoneal cavity.