ObjectiveChronic stress is an important risk factor for atherosclerotic diseases. Our previous studies have shown that chronic unpredictable mild stress (CUMS) accelerates atherosclerosis and up-regulates TLR4/NF-κB expression in apoE-/- mice. However, TLR4/NF-κB signaling whether directly contributes to the development of atherosclerosis in CUMS mice is unclear. We hypothesized that the interference of TLR4/NF-κB can ameliorate CUMS-induced inflammation and atherosclerosis in apoE-/- mice.MethodsApoE-/- mice were exposed to 12 weeks CUMS. Ad-siRNA TLR4 was given by tail vein injection (10 μl/mouse, every 5 days), and PDTC (an inhibitor of NF-κB) was given by intraperitoneal injection (60 mg/kg, once a day). Plasma corticosterone concentrations were determined by solid-phase 125I radioimmunoassay. Atherosclerosis lesions in aortic sinuses were evaluated and quantified by IMAGEPRO PLUS. Western blotting was used to detect the expression of TLR4, NF-κB, and IL-1β in aortas of the mice. Plasma lipid profiles, IL-1β, TNF-α, and MCP-1 were measured by ELISA.ResultsOur results indicated that CUMS apoE-/- mice treatment with siRNA TLR4 significantly decreased atherosclerosis and down-regulated TLR4, NF-κB, and inflammatory cytokines. PDTC also remarkably reduced atherosclerosis and the levels of IL-1β, TNF-α and MCP-1 in plasma. However, Treatment with siRNA TLR4 or PDTC had no effect on plasma corticosterone levels, and lipid profiles.ConclusionsTLR4/NF-κB pathway may participate in CUMS-induced atherosclerosis through activation of proinflammatory cytokines in apoE-/- mice. Our data may provide a new potential therapeutic target for prevention of CUMS -induced atherosclerosis.
The gut–microbiota–brain axis is the most important complex and bidirectional pathway between the gastrointestinal tract and the central nervous system. This study investigated the potential of microbe‐induced gut‐to‐brain signaling to modulate the effect of stress on depressive‐like behavior, intestinal barrier, and neuroinflammation. Result showed that fecal microbiota transplantation increased the consumption of sucrose solutions and decreased the immobility time in forced swimming test. This treatment also increased Firmicutes and decreased Bacteroidetes and Desulfobacterota at phylum levels; reduced the loss of villi and epithelial cells; suppressed the inflammatory cell infiltration in the ileum; increased the expression of ZO‐1, occludin; protected the mucosal layer function; and suppressed the high levels of inflammasomes (NLRP3, ASC, caspase‐1, and IL‐1β) in rat brain. In summary, fecal microbiota transplantation improves the depressive‐like behavior, alters the gut microbiota imbalance, and alleviates the intestinal tract inflammation, intestinal mucosa disruption, and neuroinflammation in rats induced by chronic unpredictable mild stress.
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