The Combined Effects of Particulate Matter and Exercise on Systemic Inflammatory Response and Lipid Profiles in High-Fat Diet-Treated Mice

The evidence for the subclinical effects of exercise on inflammation and blood lipids caused by obesity under particulate matter (PM) exposure conditions is limited. The purpose of this study is to examine the effects of a high-fat diet (HFD), PM exposure, and exercise on inflammation and blood lipid profiles. Forty male C57BL/6 mice, 4 weeks old, were randomly assigned to four groups (n=10 per group): the standard chow diet (STD) group, the HFD group, the HFD with PM exposure (HFD-PM) group, and the HFD with PM exposure and exercise (HFD-PM-EX) group. The mice were fed either an STD or HFD for 16 weeks, and PM was administered via tail vein injection for 8 weeks. The exercise group underwent treadmill running 5 times per week for 8 weeks. Body weight was significantly higher in the HFD and HFD-PM groups compared to the STD and HFD-PM-EX groups (p < 0.05). Serum levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were significantly higher in the HFD and HFD-PM groups compared to the STD group (p < 0.05). Additionally, the HFD-PM-EX group showed significantly lower IL-6 levels compared to the HFD and HFD-PM groups (p < 0.05). Total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) levels were significantly higher in the HFD and HFD-PM groups compared to the STD group (p < 0.05), while high-density lipoprotein cholesterol (HDL-C) levels were significantly higher in the HFD-PM-EX group than in the other three groups (p < 0.05). Furthermore, the HFD-PM-EX group exhibited significantly lower TC levels than the HFD-PM group (p<0.05), and significantly lower LDL-C levels compared to the HFD and HFD-PM groups (p < 0.05). In conclusion, our findings suggest that while an HFD can induce systemic inflammatory responses and cause detrimental changes in blood lipid profiles, additional harmful effects from PM exposure were not observed. Moreover, regular aerobic exercise may effectively mitigate HFD-induced inflammation and improve blood lipid profiles.