高脂饮食对幼鼠肿瘤坏死因子-α、抵抗素及胰岛素受体表达的影响

Effect of High Fat Diet on Levels of Tumor Necrosis Factor-α and Resistin and Expression of Insulin Receptor in Young Rats

目的研究高脂饮食对幼鼠肿瘤坏死因子-α(TNF-α)、抵抗素水平和胰岛素受体表达的影响及其与胰岛素抵抗指数(HOMA-IR)的相关性。方法 60只SD幼年大鼠随机分为高脂组和对照组,分别采用高脂饲料和普通饲料喂养。分别在喂养3周、6周、9周末测体质量、体长和血糖;放射免疫法测定其血清胰岛素(INS)和TNF-α水平;酶联免疫法测定其抵抗素;免疫组织化学法测定其胰岛素受体(INSR)。结果高脂组INS在3周、6周和9周分别为(16.35±1.77)mIU.L-1、(22.42±2.46)mIU.L-1和(34.25±3.32)mIU.L-1,对照组分别为(10.28±1.49)mIU.L-1、(9.76±1.23)mIU.L-1和(9.87±1.11)mIU.L-1;高脂组HOMA-IR在3周、6周和9周分别为3.57±1.03、4.94±1.86和7.81±1.01,对照组为2.19±0.13、2.12±0.22和2.20±0.19,二组比较差异均有统计学意义(Pa<0.01)。高脂组肝脏细胞INSR表达比对照组显著降低(P<0.05),但肌肉细胞INSR表达与对照组无统计学差异。高脂组TNF-α和抵抗素水平均与HOMA-IR呈正相关。结论高脂喂养可诱导幼年大鼠高胰岛素血症,HOMA-IR增加,胰岛素敏感性下降,其机制与TNF-α、抵抗素分泌增高及INSR表达降低密切相关。

Objective To investigate the effect of high fat diet on the levels of tumor necrosis factor（TNF-α） and resistin and expression of insulin receptor（INSR） in young rats.Methods Sixty male SD young rats were randomly divided into a high fat group and a control group,respectively,and were separately fed with the high fat diet and the normal diet.The body weight,height and fasting plasma glucose（FPG） in the rats were measured after 3 weeks,6 weeks and 9 weeks of feeding.Serum insulin（INS） and TNF-α were measured by radioim-munoassay.Resistin was measured by enzyme-linked immunosorbent assay.INSR was determined with immunohistochemistry.Results INS levels in high fat group were（16.35±1.77） mIU·L-1,（22.42±2.46） mIU·L-1,and（34.25±3.32） mIU·L-1,in 3 weeks,6 weeks and 9 weeks,respectively and INS levels in the controls were（10.28±1.49） mIU·L-1,（9.76±1.23） mIU·L-1 and（9.87±1.11） mIU·L-1 in 3 weeks,6 weeks and 9 weeks,respectively.Homeostasis model of the assessment of insulin resistance index（HOMA-IR） in high-fat group were 3.57±1.03,4.94±1.86 and 7.81±1.01 in 3 weeks,6 weeks and 9 weeks,respectively and HOMA-IR in the controls were 2.19±0.13,2.12±0.22 and 2.20±0.19 in 3 weeks,6 weeks and 9 weeks,respectively.INS and HOMA-IR were signi-ficantly higher in high fat group than those in control group（Pa0.01）.Expression of INSR in liver cells was significantly lower in high fat group（P0.05）,but its expression in the muscles was not significantly different between two groups.The levels of TNF-α and resistin were higher in high fat group than in control group,and had a positive correlation with HOMA-IR.Conclusions High fat diet in young rats may induce hyperinsulinemia,insulin resistance and decrease of insulin sensitivity.This effect is related to high excretion of TNF-α and resistin and low expression of INSR.