Wang Jing, Zhang Yue-hui, Wu Xiao-ke, Hu Min, Hou Li-hui
Department of Obstetrics and Gynecology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin 150040, China.
Zhonghua Yi Xue Za Zhi. 2009 Oct 13;89(37):2611-5.
To search for the role of impaired insulin signaling in the ovary reproductive failure and abnormal metabolic profiles in the AKT2- mouse.
Adult, female 129/C57BL/6 (AKT2-) mice were used in these studies. Littermate wide types C57BL/6J (AKT2+), as well as mutant genotypes (AKT2-). The ovaries were abstained from 6 AKT2+ type mice as wall as 6 mutant genotypes, which was used for insulin stimulated glucose uptake study. By ovary transplantation on the day of 12 weeks, three genotypic mice were constructed with body AKT2+ and ovary AKT2+ in Group A, body AKT2+ and ovary AKT2- in Group B, body AKT2- and ovary AKT2+ in Group C. The vaginal smear was done to evaluate the recovery and cyclicity of transplanted ovaries with mutant or intact AKT2. Before execution, every group was randomly separated into basal and stimulated groups in which the mice were injected recombination FSH (0.75 IU/g), and then AKT2, GSK3beta, ERK-1, CYP17 and CYP19 were determined by RT-PCR in the ovaries, and the serum were reserved for the assay of HDL-C, CHO, TG, 17-OHP progesterone, E(2), T, and LH. The weight of each mouse, their ovary and their fat pads and the estrus cycle, were also recorded.
(1) The weight of fat pads beside ovaries and fold inguen in C group were significant higher than the other groups. (2) The level of 17-OHP progesterone in B group was higher than A or C group both in basal and FSH-stimulated groups. (3) In the basal group the expression of ERK-1 and CYP17 were enhanced. Moreover in FSH-d stimulated group, the expression of ERK-1, CYP17, CYP19 and GSK3B in B group were higher as compared with the other groups.
(1) IR existed in the ovary of AKT2- type, and the mice with AKT2-type ovary had delayed cycle, PCO and high level of 17-OHP, which were similar with PCOS. (2) Metabolic dysfunction in the AKT2- mice has close relationship with whole body condition, but not defective insulin signal within ovaries. (3) Defects of insulin activity in the metabolic pathway could induce the increased expression of ERK-1 and mitogenic potential indicating the cross-talk between two pathways of insulin signaling within ovarian cells. Consequently, ovarian hyperovarianism was induced in the defective ovaries, which contribute to the enhanced response to gonadotropin and synthesis of steroid hormone.
探究胰岛素信号受损在AKT2基因敲除小鼠卵巢生殖功能衰竭及代谢异常中的作用。
本研究使用成年雌性129/C57BL/6（AKT2基因敲除）小鼠。同窝野生型C57BL/6J（AKT2基因正常）以及突变基因型（AKT2基因敲除）小鼠。取6只AKT2基因正常型小鼠以及6只突变基因型小鼠的卵巢用于胰岛素刺激的葡萄糖摄取研究。在12周龄时进行卵巢移植，构建三组基因类型小鼠：A组为身体AKT2基因正常且卵巢AKT2基因正常；B组为身体AKT2基因正常但卵巢AKT2基因敲除；C组为身体AKT2基因敲除但卵巢AKT2基因正常。通过阴道涂片评估移植的含突变型或完整AKT2基因卵巢的恢复情况及周期性。处死前，每组随机分为基础组和刺激组，给小鼠注射重组促卵泡激素（0.75 IU/g），然后通过RT-PCR检测卵巢中AKT2、糖原合成酶激酶3β（GSK3β）、细胞外调节蛋白激酶1（ERK-1）、细胞色素P450 17α羟化酶（CYP17）和细胞色素P450 19芳香化酶（CYP19）的表达，留取血清检测高密度脂蛋白胆固醇（HDL-C）、总胆固醇（CHO）、甘油三酯（TG）、17-羟孕酮（17-OHP）、雌二醇（E₂）、睾酮（T）和促黄体生成素（LH）。记录每只小鼠的体重、卵巢重量、脂肪垫重量以及发情周期。
（1）C组卵巢旁脂肪垫重量及腹股沟褶皱明显高于其他组。（2）基础组和促卵泡激素刺激组中，B组的17-OHP水平均高于A组和C组。（3）基础组中ERK-1和CYP17的表达增强。此外，在促卵泡激素刺激组中，B组ERK-1、CYP17、CYP19和GSK3β的表达高于其他组。
（1）AKT2基因敲除型小鼠卵巢存在胰岛素抵抗，AKT2基因敲除型卵巢小鼠周期延迟、多囊卵巢且17-OHP水平升高，与多囊卵巢综合征相似。（2）AKT2基因敲除小鼠的代谢功能障碍与全身状况密切相关，而非卵巢内胰岛素信号缺陷。（3）代谢途径中胰岛素活性缺陷可诱导ERK-1表达增加及有丝分裂潜能增强，提示卵巢细胞内胰岛素信号两条途径之间存在相互作用。因此，缺陷卵巢中诱导了卵巢功能亢进，这有助于增强对促性腺激素的反应及类固醇激素的合成。
