藻蓝蛋白改善自然衰老雌性小鼠生殖力的机理研究

The adjustment of one child policy in China is significance to families planning on delivering second baby. However, lots of mothers that compliance the policy are older than 35 years. Data has shown that women over 35 years have higher rates of infertility, largely due to deterioration of oocyte quality. Accumulation of reactive oxygen species (ROS) inside cells could be prevented by the administration of anti-oxidant medicine. This could in turn maintain oocyte quality. C-phycocyanin (PC) is a biliprotein enriched in Spirulina platensis that is known to possess antioxidant properties. In our previous study, we observe a significant increase in litter size after PC administration to D-galactose-induced aging mice. Further, data obtained with in vivo approach showed that PC can improve oocyte quality, inhibit ROS production, normalize mitochondria distribution, and prevent oocyte apoptosis. However, it is still not known if PC has similar function in natural aging mice, neither was known about the detailed mechanism of PC’s rescue function. By employing the model of natural aging mice, we will investigate PC’s function in litter size, ovary and oocyte quality, as well as offspring development. Moreover, the mechanisms of PC in improving fertility will be illustrated by testing ROS level, telomere length, anti-oxidant genes expression, mitochondrial function, cell apoptosis, transcriptome and proteome. This study will provide fundamental data for the application of PC in cure of aging associated degenerative reproduction.

国家计划生育政策的调整对希望孕育第二个孩子的家庭来说意义重大。但许多符合政策的妈妈年龄已超35岁。数据表明女性年龄超过35岁后生育能力显著下降，主要原因是卵子质量明显下降。有证据表明通过食用某些抗氧化药物来减少细胞内活性氧物质的积累，可以阻止卵子质量降低。藻蓝蛋白（PC）是钝顶螺旋藻中一种具抗氧化功能的藻胆蛋白。我们的前期数据表明，在半乳糖诱导的致衰小鼠模型中，PC可以显著提高致衰雌鼠的产仔数量。体内实验进一步证明，PC可以显著改善卵子成熟质量、降低ROS水平、改善线粒体分布、抑制细胞凋亡。但PC对自然衰老小鼠是否具有同样作用及其作用机理还不明确。本项目拟用自然衰老雌鼠为模型，进一步研究PC对其产子能力、卵巢卵子质量及幼仔发育的影响，并通过对ROS、端粒、抗氧化基因、线粒体功能、细胞凋亡、转录组及蛋白组的检测，明确PC改善生殖能力的作用机理，为PC在治疗衰老相关生殖缺陷的临床应用提供依据。

女性年龄超过35岁后生育能力显著下降，主要原因是由于卵母细胞质量明显降低。藻蓝蛋白（C-Phycocyanin, PC）是钝顶螺旋藻中一种具有抗氧化、抗炎和清除氧自由基功能的藻胆蛋白。本课题组前期研究结果表明，在半乳糖诱导的致衰小鼠模型中，PC可以显著提高致衰雌鼠的产仔数量。但PC对自然衰老小鼠是否具有同样作用及其作用机理还不明确。. 本项目发现PC可以改善由自然衰老引起的卵巢重量和器官系数的降低，恢复血清中AMH水平，增加卵巢超氧化物歧化酶活性，降低丙二醛含量以及阻止端粒缩短，但并不影响卵巢储备及血清中E2、FSH含量。同时，PC可以显著促进GV期卵母细胞生发泡破裂及第一极体排放，降低DNA双链断裂数目，恢复H3K4me2和H3K9me3水平，并且可以增加MII期卵母细胞数目，提高卵母细胞受精率。此外，PC可以恢复由个体自然衰老引起的纺锤体-染色体复合体形态异常。PC还可以改善卵母细胞线粒体分布，提高卵母细胞ATP水平，抑制ROS水平，减少细胞凋亡，进而提高小鼠生殖能力。为了深入了解PC改善衰老小鼠生育力下降的分子机制，我们对年轻、衰老及衰老后灌喂PC这三组小鼠的卵巢进行转录组分析。结果表明，PC可以在卵巢的转录组水平延缓生殖衰老，主要通过影响相关信号通路，从而延缓自然衰老雌性小鼠生殖力下降。这些结果为PC在治疗衰老相关生殖缺陷的临床应用提供了依据。