2. Academic Validation
  3. Ozone rectal insufflation attenuates lung inflammation by inhibiting the TLR4/NF-κB pathway through upregulation of Nrf2 in mice with COPD-like pathology

Ozone rectal insufflation attenuates lung inflammation by inhibiting the TLR4/NF-κB pathway through upregulation of Nrf2 in mice with COPD-like pathology

  • Int Immunopharmacol. 2025 Oct 19:167:115676. doi: 10.1016/j.intimp.2025.115676.
XiaoFang Zhu 1,  QinYao Zhao 2,  PengCheng Wang 2,  ShuangJiao Cao 2,  John P Williams 3,  JianXiong An 4
Affiliations

Affiliations

  • 1 Laboratory of Anesthesia and Critical Care Medicine in Colleges and Universities of Shandong Province, School of Anesthesiology, Shandong Second Medical University, Weifang, Shandong 261000, China; Laboratory of Ozone Medicine, Shandong Second Medical University, Weifang, Shandong Province, China.
  • 2 Laboratory of Anesthesia and Critical Care Medicine in Colleges and Universities of Shandong Province, School of Anesthesiology, Shandong Second Medical University, Weifang, Shandong 261000, China.
  • 3 Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
  • 4 Laboratory of Anesthesia and Critical Care Medicine in Colleges and Universities of Shandong Province, School of Anesthesiology, Shandong Second Medical University, Weifang, Shandong 261000, China; Laboratory of Ozone Medicine, Shandong Second Medical University, Weifang, Shandong Province, China; Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA. Electronic address: anjianxiong@yeah.net.
PMID: 41115352 DOI: 10.1016/j.intimp.2025.115676
Abstract

Inflammation is an important pathological feature of chronic obstructive pulmonary disease (COPD). Ozone(O3), a triatomic molecule composed of three oxygen atoms, is often referred to as an oxygen-derived reactive gas with antioxidant and anti-inflammatory properties and is considered a promising therapeutic agent for inflammatory diseases, but its effect on COPD remains unclear. In this study, a mouse model of COPD was established by intratracheal instillation of Lipopolysaccharide (LPS) and Elastase. Ozone rectal insufflation (O3-RI) can improve lung function, reduce the number of inflammatory cells, alleviates lung tissue inflammation, decrease the secretion of proinflammatory cytokines such as Interleukin-4 (IL-4), Interleukin-17A (IL-17A), Tumor Necrosis Factor-alpha (TNF-α), Interleukin-1 beta (IL-1β) and Interleukin-6 (IL-6). Additionally, O3-RI attenuated emphysema and pulmonary fibrosis. Further exploration of the mechanism of O3-RI revealed that it up-regulated the expression of Nuclear factor erythroid 2-related factor 2 (Nrf2), decreased Reactive Oxygen Species (ROS) levels, and down-regulated the expression of Toll-like Receptor 4 (TLR4), Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB), and Phosphorylated NF-κB (p-NF-κB). It was also shown that the Nrf2 inhibitor (ML385) abolished the anti-inflammatory effects in O3-RI-induced mice with COPD-like pathology, with reduced expression of Nrf2, decreased ROS content, and elevated expression of TLR4, NF-κB, and p-NF-κB. Compared with mice with COPD-like pathology treated with Nrf2 agonist (TBHQ) alone, co-treatment of Nrf2 agonist (TBHQ) and TLR4 Agonist (MPLA) did not alter Nrf2 expression but increased TLR4, NF-κB, and p-NF-κB expression and exacerbated inflammation. The present findings suggest that the protective effect of O3-RI in mice with COPD-like pathology is achieved by attenuating oxidative stress and inhibiting inflammatory responses, and the specific mechanism may be related to the increase of Nrf2 expression, which in turn inhibits the TLR4/NF-κB pathway.

Keywords

COPD; Inflammation; Nrf2; Oxidative stress; Ozone rectal insufflation; TLR4/NF-κB pathway.

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