Acute effects of personal exposure to fine particulate matter on salivary and urinary biomarkers of inflammation and oxidative stress in healthy adults.

Non-invasive bio-samples, such as saliva and urine, are promising tools for assessment of inflammation and oxidative stress biomarkers. Few studies have investigated potential responses of those biomarkers towards short-term PM2.5 exposure. We conducted a longitudinal study with 4 repeated examinations among 40 healthy, nonsmoking adults in Shanghai, China. Personal samplings were performed for PM2.5 exposure assessment. Then, five biomarkers, including C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), alpha-1 antitrypsin (A1AT) in saliva and 8-Iso-Prostaglanding F2α (8-iso-PGF2α), total antioxidant capacity (TAC) in urine, were measured. We fitted linear mixed-effect models to evaluate short-term effect of personal PM2.5 exposure on salivary and urinary biomarkers, adjusting for potential confounders of meteorology, sociodemographic characteristics and biomarker detection. We also explored sensitive time windows of exposure for different biomarkers. We found robust associations of salivary CRP, TNF-α, and urinary 8-iso-PGF2α with PM2.5 exposure, and responses of salivary inflammatory markers occurred more acutely than urinary oxidative stress markers. For instance, a 10 μg/m3 increase in PM2.5 was associated with an elevation of 5.49% (95% CI: 1.17%, 9.99%) in CRP and 7.05% (95% CI: 1.29%, 13.13%) in TNF-α both at lag 12 h, and 6.97% (95% CI: 1.33%, 12.92%) in 8-iso-PGF2α at lag 01 d. Based on non-invasive samples, this study provided evidence on effect of PM2.5 exposure on responses of systematic inflammation and oxidative stress. Sub-daily (6-12 h) and daily (≥24 h) period after PM2.5 exposure might be sensitive time window to detect the responses of salivary (i.e. CRP, TNF) and urinary biomarkers (i.e. 8-iso-PGF2α), respectively.