HUC-MSCs mitigate atherosclerosis induced by a high-fat diet in ApoE−/− mice by regulating the intestinal microbiota

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BackgroundThe mechanism underlying human umbilical cord mesenchymal stem cells (hUC-MSCs) regulating the stability of atherosclerotic plaque was explored by establishing mice models of atherosclerosis induced by a high-fat diet and hUC-MSCs intervention. MethodsThe ApoE−/− mice atherosclerosis model was constructed using a high-fat diet, and mice were divided into a normal diet group (ND), high-fat diet group (HFD), hUC-MSCs treatment group (HFDM), while the blank control (BC) consisted of C57BL/6J mice. After successful establishment of the model, the feces, hearts, and aorta of mice were collected. Morphological features were detected using HE, oil red O, and Masson staining. Afterward, 16s rRNA gene sequences was used to detect the species and abundance of the intestinal flora in mice, and an atomic force microscope (AFM) was used to detect the Young's modulus of the fibrous cap of atherosclerotic plaques. Lastly, the expression level of the inflammatory factors NLRP3, IL-1β, and IL-18 were detected via immunohistochemistry and immunofluorescence assays. ResultsIn terms of morphological characteristics, the expression level of NLRP3, Young's modulus of the fibrous cap, and plaque stability were significantly reduced in HFD, whereas the ratio of Firmicutes to Bacteroidetes (F/B) was significantly increased. Interestingly, hUC-MSCs treatment reversed the above indices, thus enhancing plaque stability. ConclusionHFD led to dysregulation of intestinal flora homeostasis and induced aberrant expression levels of NLRP3, resulting in a decrease in the Young's modulus of plaques. However, hUC-MSCs treatment improved the biomechanical properties of plaque by modulating the intestinal flora and NLRP3, thereby elevating plaque stability and minimizing the risk of plaque rupture.