Particulate Matter Exposure Induces Maternal Scalp Hair Loss After Birth in C57/B6 Mouse via Alteration of Inflammatory and Apoptotic Pathways

This study demonstrates that exposure to particulate matter (PM2.5) exacerbates postpartum hair loss in C57/B6 mice by altering inflammatory, apoptotic, and hormonal pathways. PM2.5 exposure led to structural changes in the scalp, including dermal thickening and follicular regression. Inflammatory markers such as IL-6, IL-1β, and TNF-α were elevated, and apoptotic signaling was enhanced. Additionally, PM2.5 exposure reduced progesterone receptor expression and hair follicle stem cell markers, suggesting disrupted hormonal signaling and stem cell function. These findings highlight the specific vulnerability of postpartum mice to PM2.5-induced hair loss, which was not observed in non-pregnant mice.