Repeated Short-Term Intratracheal Exposure to Urban Particulate Matter Has No Apparent Adverse Effects on Female Reproductive Outcomes in Mice

Urban particulate matter (UPM) is a major environmental pollutant known to induce systemic inflammation. While its respiratory toxicity is well-documented, the potential vulnerability of the female reproductive system to inhaled UPM remains a critical concern. In this study, we evaluated female reproductive outcomes in a murine model following repeated short-term intratracheal instillation of UPM (40–200 mg/kg) for a month. Our results demonstrate that while UPM exposure induced robust, dose-dependent pulmonary inflammation, characterized by immune cell infiltration (CD45+, F4/80+, and Ly6G+) and upregulation of pro-inflammatory (Il-6, Il-1β, and Tnfα) and fibrotic (Col1a1 and Tgfβ1) markers, no apparent adverse effects were observed in the reproductive endpoints examined. No significant alterations were observed in maternal pregnancy outcomes, including oocyte recovery rates, fertilization competence, gestation duration, litter size, and postnatal development of pups. Furthermore, the mRNA expression of inflammatory markers in the ovaries and uteri was not detectable. Direct in vitro exposure of two-cell embryos to UPM did not interfere with preimplantation embryo development. Although benzanthracene slightly reduced the blastocyst formation rate, UPM and polycyclic aromatic hydrocarbons, major toxic components of UPM, did not severely compromise preimplantation embryo development in vitro. In conclusion, these findings suggest that marked UPM-induced pulmonary inflammation is not accompanied by substantial alterations in the female reproductive outcomes examined under short-term exposure conditions.