Airborne fine particulate matter (FPM) is a major environmental health threat associated with inflammatory responses. Although previous studies have reported FPM-induced inflammation in macrophage cell lines, the effects of FPM on primary bone marrow-derived macrophages (BMMs) and systemic nitric oxide metabolite (NOx) levels have not been fully characterized. This study evaluated whether low-dose FPM exposure induces inflammatory responses in vitro and in vivo . BMMs isolated from ICR mice were treated with FPM (0.0–12.5 μg/mL), and proinflammatory cytokine production was measured by enzyme-linked immunosorbent assay. For in vivo assessment, mice were administered FPM (7.5 mg/kg) by intraperitoneal injection under short-term exposure conditions, and serum NOx levels were quantified using the Griess assay. Exposure to FPM at 6.25 and 12.5 μg/mL significantly increased tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 production by BMMs compared with the control group (p < 0.05). In vivo , serum NOx levels were also significantly elevated in FPM-exposed mice compared with the control group (p = 0.026), consistent with results observed in the lipopolysaccharide-treated positive control group (p = 0.004). These findings suggest that low-dose transient FPM exposure activates innate immune cells and induces systemic inflammatory responses, supporting the potential role of FPM in the pathogenesis of inflammatory diseases.

Introduction
Materials and Methods
    1. Experimental animals and reagents
    2. Experimental design
    3. Cell culture
    4. Enzyme-linked immunosorbent assay
    5. Measurement of serum nitric oxide metabolites
    6. Statistical analysis
Results
    1. Low dose fine particulate matter exposurepromotes inflammatory cytokine secretion in innateimmune cells
    2. Low dose fine particulate matter exposure inducessystemic inflammatory response in mice
Discussion
Funding
Acknowledgements
Conflicts of Interest
References

• Hye Young Mun(Department of Dental Hygiene, College of Health Sciences, Yonsei University, Wonju 26493, Republic of Korea)
• Jung Yun Kang(Department of Dental Hygiene, College of Health Sciences, Yonsei University, Wonju 26493, Republic of Korea) Corresponding author
• Septika Prismasari(Department of Dental Hygiene, College of Health Sciences, Yonsei University, Wonju 26493, Republic of Korea, Department of Preventive and Community Dentistry, Faculty of Dentistry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia)