HFD-induced LPS translocation and elevated blood lipids exacerbated the inflammatory response in allergic rhinitis

Allergic rhinitis (AR) is one of the most prevalent chronic diseases, with studies indicating that a high-fat diet (HFD) may heighten susceptibility to AR. This study aims to investigate the impact of HFD on ovalbumin (OVA)-induced AR using both an OVA-sensitized rat model and a macrophage model treated with palmitic acid (PA). The systemic effects of HFD were explored with respect to intestinal barrier integrity, serum lipids and lipopolysaccharide (LPS) levels, and inflammatory response. In AR rats fed with HFD, there was a reduction in the expression of tight junction proteins in colon tissues, increased serum levels of lipids and LPS, and elevated inflammatory responses in both nasal lavage fluid (NLF) and serum. Additionally, there was enhanced NF-κB and NLRP3 inflammasome activity observed in both nasal and colon tissues. In vitro experiments demonstrated that PA and LPS synergistically amplified inflammatory responses in THP-1-derived macrophages, paralleling the systemic findings. These results suggest that HFD-induced intestinal barrier dysfunction facilitates the translocation of LPS into the bloodstream. Elevated serum LPS level, together with increased blood lipids levels, may exacerbate the inflammatory response in AR through the activation of NF-κB and NLRP3 inflammasome.