Lee Bo Myeong, Chun Ju Lan, Lee Ji Hye, Kim Eun Young, Park Kang-Sun, Lee Jin-Hee, Daigneault Bradford W, Smith George W, Kim Keun Jung, Chang Kyu-Tae, Lee Sang-Rae, Kim Sun-Uk, Choi Seon-A, Lee Kyung-Bon, Kim Min Kyu
1 Department of Animal Science and Biotechnology, College of Agriculture and Life Science, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea.
2 Laboratory of Mammalian Reproductive Biology and Genomics, Michigan State University, East Lansing, MI, USA.
Reprod Sci. 2018 May;25(5):759-772. doi: 10.1177/1933719117725829. Epub 2017 Aug 28.
Mammalian oocytes resume maturation when removed from follicles and cultured in vitro. During folliculogenesis, oocytes are bathed in follicular fluid (FF), which provides an important and specialized microenvironment for oocyte competence. Follistatin (FST) is one component of FF that may play a role in oocyte maturation and embryo development. This study was conducted to examine possible effects of FST on porcine oocyte competence and embryo development. Exogenous FST in oocyte maturation medium for 22 or 44 hours did not improve nuclear maturation and had no effect on good quality cumulus-oocyte complexes (COCs). However, FST improved blastocyst rates in embryos derived from oocytes with less than 2 layers of cumulus. Follistatin treatment of the poor quality COC group increased transcript levels for genes indicative of oocyte quality. Transcript levels were also altered for cumulus expansion-related genes in response to FST when measured during the germinal vesicle breakdown stage. Interestingly, high-quality oocytes remained at germinal vesicle stage much longer than low-quality oocytes, FST treatment induced temporary blockage of spontaneous meiotic resumption when added during culture of both good and poor quality COCs, and levels of cyclic guanosine monophosphate (cGMP) were higher in FST-treated versus untreated groups for both good and poor quality oocytes. In conclusion, FST treatment of porcine oocytes during in vitro maturation can rescue competency of poor quality oocytes to develop to blastocyst stage following in vitro fertilization. Beneficial effects of addition of FST to culture medium may be mediated by inhibiting degradation of cGMP and temporarily delaying nuclear maturation.
哺乳动物卵母细胞从卵泡中取出并在体外培养时会恢复成熟。在卵泡发生过程中，卵母细胞浸泡在卵泡液（FF）中，卵泡液为卵母细胞的发育能力提供了重要且特殊的微环境。卵泡抑素（FST）是卵泡液的一种成分，可能在卵母细胞成熟和胚胎发育中发挥作用。本研究旨在探讨FST对猪卵母细胞发育能力和胚胎发育的可能影响。在卵母细胞成熟培养基中添加外源性FST 22或44小时，并未改善核成熟情况，对优质卵丘 - 卵母细胞复合体（COC）也没有影响。然而，FST提高了来自卵丘层数少于2层的卵母细胞所发育胚胎的囊胚率。对质量较差COC组进行Follistatin处理可增加指示卵母细胞质量的基因的转录水平。在生发泡破裂阶段进行检测时，卵丘扩展相关基因的转录水平也因FST而发生改变。有趣的是，高质量卵母细胞在生发泡阶段停留的时间比低质量卵母细胞长得多，在对优质和劣质COC进行培养时添加FST会诱导自发减数分裂恢复的暂时阻滞，并且优质和劣质卵母细胞的FST处理组中环状鸟苷单磷酸（cGMP）水平均高于未处理组。总之，在体外成熟过程中对猪卵母细胞进行FST处理可以挽救劣质卵母细胞在体外受精后发育至囊胚阶段的能力。向培养基中添加FST的有益作用可能是通过抑制cGMP的降解和暂时延迟核成熟来介导的。
