早期高脂膳食对幼鼠胰岛细胞结构和胰岛素敏感性的影响

Effect of early high fat diet on pancreatic β cellularity and insulin sensibility in young rats

目的研究幼年期高脂饮食对糖代谢、胰岛素敏感性和胰岛β细胞结构的影响。方法 60只雄性幼年SD大鼠随机分为高脂组和对照组,分别采用高脂和普通饲料喂养。在喂养3、6、9周末,测体重、身高,取内脏脂肪称重;测定空腹血糖和空腹血清胰岛素;电镜观察胰腺超微结构变化。结果自4周末高脂组体重显著高于对照组(P<0.05),其内脏脂肪重量自3周末显著高于对照组(P<0.05),均随时间延长其差异更显著(P<0.01);两组空腹血糖于第3、6、9周末比较差异均无统计学意义;高脂组空腹胰岛素水平和HOMA-IR指数均显著高于对照组(P<0.01);高脂饲养6周时,幼鼠胰岛β细胞粗面内质网扩张,线粒体轻度肿胀。结论生命早期高脂膳食可诱导幼鼠胰岛素敏感性下降、胰岛素抵抗;β细胞内质网扩张,可能是肥胖损伤β细胞的早期信号。

Objective To study the effects of early high fat diet on sugar metaboliam,insulin sensibility and pancreatic β cellularity in young rats.Methods Sixty male weaned young rats were randomly fed with high fat diet （high fat group） and normal diet （control group）.The body weight,viscus fattiness and fasting plasma glucose （FPG） were measured after 3,6 and 9 weeks.Serum insulin level was measured with radioimmunoassay.The ultrastructure of pancreas was observed under an electricmicroscope.Results The high fat group had significantly higher body weight and visceral fat weight than the control group after 3 weeks.There were no significant differences in the FPG level between the two groups at all time points.The levels of fasting insulin and HOMA-IR in the high fat group were significantly higher than those in the control group after 3,6 and 9 weeks （P〈0.01）.Dilation of rough endoplasmic reticulum and mild swelling of mitochondria of islet β-cells were observed in the high fat group after 6 weeks.Conclusions Early high fat diet may induce a reduction in insulin sensitivity and produce insulin resistance in young rats.Endoplasmic reticulum expansion in β-cells may be an early sign of β-cell damage due to obesity.