Lonicerae japonicae flos Polyphenols Attenuate Inflammation-Related Ferroptosis and Gut Microbiota Dysbiosis in LPS-Induced Acute Lung Injury in Mice

Background/Objectives: Acute lung injury (ALI) currently lacks safe and effective therapeutic strategies with low toxicity. Lonicerae japonicae flos, a traditional herb and functional food, contains polyphenols as its principal active components. This study investigated whether Lonicerae japonicae flos polyphenols (LJP) could exert protective effects against lipopolysaccharide (LPS)-induced ALI in mice. Methods: Eighty-four male C57BL/6J mice were randomly divided into seven groups and treated daily for 7 days with LJP (200, 100, or 50 mg/kg), liproxstatin-1 (10 mg/kg), dexamethasone (5 mg/kg), or saline (control and model groups). Subsequently, another thirty-six mice were used for the fecal microbiota transplantation (FMT) experiment. All groups except the control group received intratracheal instillation of LPS (5 mg/kg) to induce ALI. Results: LJP treatment significantly ameliorated lung histopathological damage and gut microbiota dysbiosis. Lung proteomics analysis revealed the enrichment of the NF-κB and ferroptosis pathways. Mechanistically, LJP downregulated pro-inflammatory factors (IL-6, TNF-α, and IL-1β) by suppressing activation of the TLR4/MyD88/NF-κB pathway. Meanwhile, LJP upregulated SOD and GSH levels, thereby suppressing the accumulation of ROS, GSSG, Fe2+, and MDA, which were closely related to the activation of the Nrf2/HO-1 and Sirt3/Nrf2/GPX4 pathways. Furthermore, LJP modulated the gut microbiota and promoted short-chain fatty acid (SCFA) production by elevating the relative abundance of Akkermansia muciniphila and Faecalibaculum. Intriguingly, FMT results confirmed that the LJP-derived gut microbiota markedly alleviated lung tissue injury and intestinal barrier damage in ALI mice. Conclusions: This study demonstrated that LJP could reshape the gut microbiota to enhance the production of SCFAs and inhibit inflammation-related ferroptosis in ALI mice.