Inflammatory bowel disease(IBD)is a chronic inflammatory disease of the gastrointestinal tract that includes Crohn's disease and ulcerative colitis.IBD may be caused by complex interactions between genetic susceptibility,environmental factors,and alterations in the gut microbiota,resulting in dysregulated innate and adaptive immune responses.Recent studies have identified macrophages in the intestinal inflammatory response as having the plasticity to not only regulate inflammation,but also to promote tissue repair and healing.As aberrant macrophage polarization occurs during the development of IBD,the balance between the phenotype and function of pro-inflammatory M1 and anti-inflammatory M2 macrophages is regulated by extracellular and intracellular stimuli,and this process is therefore expected to be a potential target for new therapeutic approaches.This article reviewed the progress of research on macrophage polarization in IBD.

Objective:To analyze the effect of depressive state on Alzheimer's disease(AD)mice,3xTg-AD mice were stimulated with chronic social frustration stress(CSDS)and chronic mild unpredictable stress(CUMS),to estab-lish an early AD-induced depression mouse model,and to detect cognitive and behavioral changes,activation of micro-glia in the hippocampus and neuronal loss.Methods:Three-month-old mice were subjected to 8-day stress stimulation alternately,the depressive state of the mice was evaluated by behavior,the evaluation criteria were formulated,and the cognitive behavior was detected and analyzed,and the hippocampal brain tissue sections were stained with immunofluo-rescence to observe the deposition of β-amyloid(Aβ)and the aggregation of microtubule-associated protein(tau),mi-croglia activation and neuronal loss.Results:Depression-related behavioral results showed that the CSDS+CUMS group had depression-related phenotypes.Cognitive-behavioral testing showed that the new object recognition index of the mice in the CSDS+CUMS group was significantly reduced(P＜0.05),and the Morris water maze showed that the spatial memory ability of the CSDS+CUMS group was significantly reduced(P＜0.05),but there was no obvious fear memory loss in the CSDS+CUMS group in the conditioned fear experiment.The results of immunofluorescence staining showed that Aβ deposition appeared in the hippocampus at 4 months of age,the activated microglia increased(P＜0.001),and a certain degree of neuronal loss appeared in the CSDS+CUMS group(P＜0.001);At 8 months of age,the CSDS+CUMS group showed tau protein aggregation early.Conclusion:We established a model of AD-induced de-pression in AD mice,in which 3xTg-AD mice experienced early decline in learning memory and increased AD-related pathological deposition of neurons in the hippocampus,accompanied by microglial activation and neuronal loss.