Indoleamine 2,3-dioxygenase 1 (IDO1) promoted the activation of inflammatory response in the brain tissue of Alzheimer’s disease mice by regulating NF-κB pathway

Objective To investigate the regulatory mechanism of IDO1 on brain tissue damage in Alzheimer’s disease (AD) mice. Methods APP/PS1 mice (AD model mice) and C57BL/6J mice were treated with IDO1 inhibitor 1-MT. Behavioral changes were assessed using the open field test, and histopathological changes were analyzed using HE staining, Nissl staining, and transmission electron microscopy. TUNEL staining and immunofluorescence were used to detect cell apoptosis and the expression of IDO1 and GFAP, respectively. Metabolomics was analyzed using liquid chromatography-mass spectrometry. An in vitro AD cell model was established, and inflammatory factor levels were measured using ELISA/qPCR, while NF-κB pathway activation was assessed using WB. Results In vivo experiments showed that compared with the model group mice, 1-MT intervention improved behavioral abnormalities in AD mice, reduced hippocampal tissue damage, decreased neuronal apoptosis, and downregulated the expression of IDO1 and GFAP. In vitro experiments demonstrated that interfering with IDO1 could decrease the levels of IL-1β, TNF-α, and IL-6, reduce GFAP expression, and inhibit p65 phosphorylation. Conclusion Interfering with IDO1 can inhibit the NF-κB pathway, reduce the release of inflammatory factors, and improve brain tissue damage in AD mice.