胰岛素抵抗及子宫内膜增殖大鼠模型中脂肪因子和PI3K/AKT信号通路相关蛋白的表达

Insulin Resistance and Endometrial Hyperplasia Alter the Adiponectin System and PI3K/AKT Signaling in Rats

目的:观察有胰岛素抵抗及子宫内膜增殖大鼠模型中血浆脂联素(Adipo)等脂肪因子的水平,检测Adipo和脂联素受体(AdipoR)在大鼠子宫组织中的表达,并探讨其分子生物学机制。方法:选取8周龄Sprague-Dawley(SD)大鼠45只(每组9只),分别给予普通饮食(StD组)和高脂饮食(HFD组)40周。将StD组分为对照C组(普通饮食+假去势手术+对照溶剂)、NO组(普通饮食+去势手术+对照溶剂)、NE组(普通饮食+去势手术+17β-雌二醇灌胃),HFD组分为FO组(高脂饮食+去势手术+对照溶剂)和FE组(高脂饮食+去势手术+17β-雌二醇灌胃)。应用酶联免疫吸附(ELISA)检测小鼠血浆中脂肪因子水平,实时荧光定量PCR、Western Blotting和免疫组化检测子宫内膜中脂肪因子的水平,免疫组化检测子宫内膜中PTEN、AMPK和PI3K/AKT信号通路相关蛋白的表达。结果:①与NE组大鼠相比,FE组大鼠子宫腔上皮细胞和腺上皮细胞的高度、肌层的厚度显著增加(P<0.05)。②与对照C组相比,子宫内膜增生组(NE组和FE组)大鼠血浆Adipo水平显著降低(P<0.05),FO组大鼠血浆Adipo显著升高(P<0.05)。③在雌激素的作用下(NE组和FE组)子宫组织中Adipo mRNA的表达增多:与NO组大鼠相比,NE组大鼠子宫组织中Adipo mRNA水平显著升高(P<0.05);与FO组大鼠相比,FE组大鼠Adipo mRNA水平也显著升高(P<0.05)。大鼠子宫中AdipoR1 mRNA和AdipoR2 mRNA水平在各组之间差异无统计学意义(P>0.05)。与对照C组相比,FE组大鼠子宫组织中Adipo蛋白的表达明显降低(P<0.05)。④FE组子宫PTEN和p-AMPK蛋白的表达显著低于对照C组(P<0.05),PI3Kp85α、p-AKT蛋白表达显著高于对照C组(P<0.05)。结论:长期高脂饮食诱导大鼠的胰岛素抵抗可协同17β-雌二醇刺激子宫内膜增殖;胰岛素抵抗和雌激素影响血浆Adipo的水平;胰岛素抵抗和雌激素的协同作用使大鼠子宫内膜PTEN的表达降低、AMPK通路可能被抑制、PI3K/AKT信号通路可能被激活。

Objective:To examine the molecule expression and mechanism of adiponectin and it's receptors in rat model with insulin resistance(IR)and endometrial hyperplasia(EH).Methods:45 female Sprague-Dawley rats(8 weeks)were chosen.27 rats were fed with standard diet(StD),and 18 rats were fed with high-fat diet(HFD).After 40 weeks,rats were assigned to 5 groups:C[control,standard diet(StD)+sham-ovariectomized(OVX)+vehicle],NO(StD+OVX+vehicle),NE[StD+OVX+17β-estradiol(E2)],FO(HFD+OVX+vehicle),and FE(HFD+OVX+E2).Circulating adiponectin was determined by ELISA.protein expression was determined by Western Blotting and immunostaining.mRNA level was determined by qRT-PCR.Results:①In rat with IR and EH(group FE),the height of endometrial and glandular epithelium and myometrium were higher than rat only with EH(group NE).②Compared to C group,plasma adiponectin was lower in NE and FE groups(P<0.05),and was higher in FO group(P<0.05).③E2 increased the expression of adiponectin mRNA:adiponectin mRNA level in group NE was higher than group NO,and the level in FE rats was also higher than that in FO rats(P<0.05).There was no significant difference in the mRNA levels for adiponectin receptors in any of the groups(P>0.05).Compared to group C,the protein expression of adiponectin was significantly lower in group FE(P<0.05).④Immunohistochemistry analysis showed that the expression of PTEN and p-AMPK in FE group were significantly lower than group C,whereas the expression of PI3Kp85αand p-AKT in group FE were significantly higher than group C(P<0.05).Conclusions:The combined action of insulin resistance and estradiol may regulate the level of plasma adiponectin,as well as lead to the reduction of endometrial PTEN expression,the inhibition of AMPK pathways and the activation of PI3K/AKT signaling pathways.