Heat exposure impairs porcine oocyte quality with suppressed actin expression in cumulus cells and disrupted F-actin formation in transzonal projections  

作　　者：Chao Yin Jie Liu Zhanglin Chang Bin He Yang Yang Ruqian Zhao 

机构地区：[1]MOE Joint International Research Laboratory of Animal Health&Food Safety,Nanjing Agricultural University,Nanjing,Jiangsu,China [2]Key Laboratory of Animal Physiology and Biochemistry,Ministry of Agriculture,Nanjing Agricultural University,No.1 Weigang Road,Nanjing 210095,China [3]College of Animal Science and Technology,Jiangxi Agricultural University,Nanchang,Jiangxi,China

出　　处：《Journal of Animal Science and Biotechnology》2020年第3期703-714,共12页畜牧与生物技术杂志（英文版）

基　　金：This work was supported by the National Key Research and Development Program of China(Grant number 2016YFD0500502);the National Basic Research Program of China(Grant number 2014CB138502);the Priority Academic Program Development of Jiangsu Higher Education Institutions;and the Jiangsu Collaborative Innovation Center of Meat Production and Processing,Quality and Safety Control.

摘　　要：Background:Transzonal projections(TZPs)constitute a structural basis for the communication between the oocyte and its surrounding cumulus cells(CCs),which play critical roles in promoting the oocyte maturation.Previously we found that heat stress(HS)causes loss of TZPs in porcine cumulus-oocyte complexes(COCs)with decreased density of filamentous actin(F-actin).However,the time-course responses of F-actin and its monomeric actins(β-actin andγ-actin)during the in vitro maturation of oocytes remain unclear.Results:In this study,excised porcine ovaries were exposed to HS at 41.5°C for 1 h before COCs were isolated and matured in vitro for 44 h.HS significantly reduced oocyte quality,characterized by impaired cumulus expansion,delayed meiotic resumption and lower survival rate and polar body extrusion rate,as well as decreased expression of mitochondrial DNA-encoded genes and elevated mitochondrial reactive oxygen species concentration.Expression ofβ-actin andγ-actin in CCs increased gradually with oocytes maturation,which was significantly reduced in HS group,especially at 24 h and/or 44 h of in vitro maturation.By contrast,the number of TZPs and the fluorescence intensity of F-actin in zona pellucida decreased gradually during oocytes maturation,which were significantly reduced by HS at 24 h of in vitro maturation.Moreover,colocalization analyses revealed bothβ-actin andγ-actin contribute to the F-actin formation in porcine TZPs,and the colocalization of F-actin with GJ protein connexin 45 was significantly reduced in heat-exposed COCs.Conclusions:The results indicate that the suppression of actin expressions in CCs,which may lead to the F-actin unstabilization in TZPs,will subsequently contribute to the compromised quality of oocytes under HS.

关 键 词：ACTIN Cumulus cell GILT Heat stress OOCYTE 

分 类 号：S852.2[农业科学—基础兽医学]