In Utero Ultrafine Particulate Exposure Yields Sex- and Dose-Specific Responses to Neonatal Respiratory Syncytial Virus Infection

Exposure to particulate matter (PM) is associated with lower respiratory tract infections. The role of ultrafine particles (UFPs, <= 0.1 mu m) in respiratory disease is not fully elucidated, especially in models of immunologically immature populations. To characterize the effects of maternal UFP exposure on neonatal infection, we exposed time-mated C578 1 / 6 n mice to filtered air or UFPs at a low dose (LD, similar to 55 mu g/m(3)) and high dose (HD, similar to 275 mu g/m(3)) throughout gestation. At 5 days of age, offspring were infected with a respiratory syncytial virus (RSV) strain known to mimic infant infection or sham control. Offspring body weights were significantly reduced in response to infection in the LD RSV group, particularly females. Pulmonary gene expression analysis demonstrated significantly increased levels of oxidative stress- and inflammation-related genes in HD-exposed male offspring in sham and RSV-infected groups. In males, the highest grade of inflammation was observed in the HD RSV group, whereas in females, the LD RSV group showed the most marked inflammation. Overall, findings highlight neonatal responses are dependent on offspring sex and maternal UFP dose. Importantly, infant RSV pathology may be enhanced following even low dose UFP exposure signifying the importance of preventing maternal exposure.

Automated summary

This study investigates the impact of maternal exposure to ultrafine particles on neonatal infection, revealing that infant RSV pathology may be exacerbated following low dose UFP exposure, especially in female offspring. The findings emphasize that neonatal responses are dependent on offspring sex and maternal UFP dose.