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目的探讨脂肪组织炎症在CYP1B1基因缺失小鼠保护营养性肥胖及其胰岛素抵抗中的作用和可能机制。方法选择3周龄SPF级CYP1B1基因敲除(KO)和野生型(WT)雄性小鼠各16只,给予低(LFD)、高脂肪(HFD)饲料,每组8只,连续喂养11周。采用实时定量RT-PCR测定脂肪组织中巨噬细胞相关炎症因子、胰岛素通路中相关基因表达的变化,利用免疫荧光观察巨噬细胞在脂肪组织中浸润及炎症通路中核转录因子(NFκB)的活化状态。结果经过11周喂养,KO小鼠血糖及胰岛素水平较WT小鼠降低(P<0.05),胰岛素敏感性较WT小鼠升高(P<0.05)。高脂膳食可增加WT小鼠附睾脂肪组织巨噬细胞的浸润;与WT小鼠相比,低脂饮食下KO小鼠脂肪组织有少量巨噬细胞,但高脂膳食喂养并不进一步增加KO小鼠脂肪组织中巨噬细胞的浸润。与WT小鼠相比,低脂饮食下KO小鼠脂肪组织巨噬细胞表面标志基因Emr1、CD68,炎症因子TNF-αI、L-6,炎症因子受体CCR2、CSFR1以及胰岛素受体底物(IRS)、胰岛素受体(InsR)mRNA的表达水平均上调(P<0.05或P<0.01)。免疫荧光结果显示,KO小鼠脂肪组织炎症通路的关键因子NFκB活化移位。结论 CYP1B1基因敲除对小鼠营养性肥胖及胰岛素抵抗有保护作用,其机制可能是通过激活小鼠脂肪组织炎症通路调节机体胰岛素信号通路中关键因子的表达水平,从而发挥改善营养性肥胖相关胰岛素抵抗作用。
Objective To investigate the role and possible mechanism of adipose tissue inflammation in the protection of nutritional obesity and insulin resistance in CYP1B1-deficient mice. Methods Sixteen SPF-type CYP1B1 knockout (KO) and wild-type (WT) male mice, each at 3 weeks of age, were given low and high fat (HFD) diets, 8 for each group, for 11 weeks. Real-time quantitative RT-PCR was used to detect the changes of macrophage-associated inflammatory factors and insulin-related genes in adipose tissue. Immunofluorescence was used to observe the infiltration of macrophages in adipose tissue and the activation of nuclear factor-kappa B (NFκB) in inflammatory pathways . Results After 11 weeks of feeding, the blood glucose and insulin levels of KO mice were lower than those of WT mice (P <0.05). The insulin sensitivity of KO mice was higher than that of WT mice (P <0.05). High-fat diet increased the infiltration of epididymal adipose tissue in WT mice. Compared with WT mice, KO mice had a small amount of macrophages in adipose tissue under low-fat diet, but did not increase KO in high fat diet Infiltration of macrophages in murine adipose tissue. Compared with WT mice, the expression of macrophage surface marker genes Emr1, CD68, TNF-αI, L-6, CCR2, CSFR1 and insulin receptor substrate ( IRS) and insulin receptor (InsR) mRNA expression were up-regulated (P <0.05 or P <0.01). Immunofluorescence results showed that the activation of NFκB, a key factor in the inflammatory pathway of adipose tissue in KO mice, was activated. Conclusions CYP1B1 knockout has a protective effect on nutritional obesity and insulin resistance in mice. The mechanism may be that the activation of mouse adipose tissue inflammatory pathways regulates the expression of key factors in the body’s insulin signaling pathway, thereby improving the nutrition-related obesity-related insulin Resistant effect.