ABSTRACT
Objective To investigate stress induced Nox-4 expression and to explore its role in adipose inflammation. Methods Twenty male Kunming mice were randomly divided into two groups ( n=10 each) , chronic restraint stress group and control group. Stress mice were restrained in self-made restraint device for 2 hours per day for 14 days. HE staining, immunohistochemistry, RT-PCR, and ELISA were used to analyze the expression of Nox-4, CD11b, antioxidant protein ( Mn SOD, GSH-Px, Catalase), adipocytokines ( adiponectin, MCP-1, IL-6, TNF-a). Results White adipose tissue (WAT) of stress mice inguinal fat pad significantly shrank compared to control group. HE staining showed that there were a large number of mononuclear cells, neutrophils, eosinophils, and cell infiltration reactions and inflammatory changes in WAT of stress mice. The stress significantly increased CD11b-positive cells and the expression of mF4/80, CD68. The concentration of serum FFA in stress group increased significantly, nearly twice of the control group ( P<0.01) . Nox-4 positive staining cells in stress WAT were deeper and more abundant. The level of Nox-4 in stress WAT was significantly higher than that of control group(P<0.01). The levels of antioxidant proteins such as Mn-SOD, GSH-Px, and catalase in stress WAT were significantly lower than those of control group (P<0.01). The expression levels of adiponectin in stress WAT were significantly reduced as compared to control group ( P<0.01) . The levels of MCP-1, IL-6 and TNF-α in stress WAT were significantly higher than those in control group (P<0.01). Conclusion Stress may lead to imbalance of adipose oxidation/antioxidant system and abnormal expression of adipocytokines, which may result in adipose inflammation.
ABSTRACT
Glucagon-like peptide 1 (GLP-1), a kind of gut hormone, is used in the treatment of type 2 diabetes (T2D). Emerging evidence indicates that GLP-1 has anti-inflammatory activity. Chronic inflammation in the adipose tissue of obese individuals is a cause of insulin resistance and T2D. We hypothesized that GLP-1 analogue therapy in patients with T2D could suppress the inflammatory response of macrophages, and therefore inhibit insulin resistance. Our results showed that GLP-1 agonist (exendin-4) not only attenuated macrophage infiltration, but also inhibited the macrophage secretion of inflammatory cytokines including TNF-β, IL-6, and IL-1β. Furthermore, we observed that lipopolysaccharide (LPS)-induced macrophage conditioned media could impair insulin-stimulated glucose uptake. This effect was compensated by treatment with the conditioned media from macrophages treated with the combination of LPS and exendin-4. It was also observed that exendin-4 directly inhibited the activation of NF-κB in macrophages. In conclusion, our results indicated that GLP-1 improved inflammatory macrophage-derived insulin resistance by inhibiting NF-κB pathway and secretion of inflammatory cytokines in macrophages. Furthermore, our observations suggested that the anti-inflammatory effect of GLP-1 on macrophages can contribute to GLP-1 analogue therapy of T2D.