Restraint Stress on Female Mice Diminishes the Developmental Potential of Oocytes. Issue 6 (June 2015)

• Record Type: Journal Article
• Authors: Wu, Xiu-Fen; Yuan, Hong-Jie; Li, Hong; Gong, Shuai; Lin, Juan; Miao, Yi-Long; Wang, Tian-Yang; Tan, Jing-He
• Is Part Of: Obstetrical & gynecological survey. Volume 70:Issue 6(2015)
• Publication Date: 2015-06
• Subjects: Obstetrics -- Periodicals; Gynecology -- Periodicals; Generative organs, Female -- Surgery -- Periodicals; 618
• DOI: 10.1097/01.ogx.0000467231.03943.2d
• Languages: English
• ISSNs: 0029-7828

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>ABSTRACT</title> <p>Female mice and rats exposed to psychological restraint stress during pregnancy show impaired embryo development and reduced pregnancy rates and litter sizes. Restraint stress in female mice causes chromosome abnormalities and impairs the developmental potential of oocytes. The mechanisms underlying these effects appear to be related to changes in chromatin configuration during maturation and/or epigenetic histone modifications. Two classes of chromatin configuration occur in fully grown germinal vesicle stage oocytes: the nonsurrounded nucleolus (NSN) and the surrounded nucleolus (SN) oocytes. Histone acetylation leads to relaxation of chromatin structure and correlates with gene activation, whereas histone deacetylation leads to condensation of chromatin structure and correlates with gene repression. The relationship between oocyte growth and increased histone acetylation and methylation or that between oocyte growth and chromatin configuration and competence is unclear and can only be determined using a system where the SN configuration can be dissociated from histone modification.</p> <p>The aim of this study was to examine the effects of restraint stress on early stages of oocyte development and to specifically investigate the role of the NSN-to-SN transition and the acquisition of certain histone modifications on the developmental potential of oocytes. Female mice were subjected to restraint stress for 24 or 48 hours or for 23 days before being examined for oocyte chromatin configuration, histone modification, and development both in vitro and in vivo.</p> <p>Restraint stress for 48 hours or 23 days impaired NSN-to-SN transition, histone acetylation, and methylation in SN oocytes and was associated with impaired oocyte developmental potential. Although the percentage of stressed SN oocytes returned to normal following a 48-hour postrestraint recovery, neither histone acetylation/methylation in SN oocytes nor oocyte competence to sustain early embryonic development recovered following postrestraint recovery with equine chorionic gonadotropin injection. Oocyte histone modification was expedited to early completion after priming unstressed mice with equine chorionic gonadotropin. Unlike levels of acetylated and methylated histones, which decreased in the stressed SN oocytes, the level of phosphorylated H3S10 increased significantly following exposure of the oocytes to stress.</p> <p>These data indicate that restraint stress in female mice impaired oocyte development potential through disturbance of histone modifications and suggest that SN configuration was uncoupled from increased histone acetylation/methylation in the stressed oocytes. Epigenetic histone modifications in the SN oocytes are more closely correlated with increased oocyte developmental potential than are changes in chromatin configuration.</p> </sec> </abstract>