Rahman Mohammad Bozlur, Schellander Karl, Luceño Núria Llamas, Van Soom Ann
Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium; Institute of Animal Science, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
Institute of Animal Science, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
Theriogenology. 2018 Jun;113:102-112. doi: 10.1016/j.theriogenology.2018.02.012. Epub 2018 Feb 12.
Currently, the world is facing the negative impact of global warming on all living beings. Adverse effects of global warming are also becoming obvious in dairy cattle breeding. In dairy bulls, low fertility has frequently been reported during summer season especially in tropical or subtropical conditions. Typically, spermatozoa at post-meiotic stages of development are more susceptible to heat stress. During this period extensive incorporation of histone modifications and hyperacetylation turns the chromatin into an unstable conformation. These unstable forms of chromatin are thought to be more vulnerable to heat stress, which may have an effect on chromatin condensation of spermatozoa. Spermatozoa with altered chromatin condensation perturb the dynamics of DNA methylation reprogramming in the paternal pronucleus resulting in disordered active DNA demethylation followed by de novo methylation patterns. In addition, there was a tendency of decreased size in both paternal and maternal pronuclei after fertilization of oocytes with heat-stressed spermatozoa, leading to lower fertilization rates. In this review, we will focus on the mechanisms of heat stress-induced sperm defects and provide more detailed insights into sperm-borne epigenetic regulations.
当前，世界正面临全球变暖对所有生物的负面影响。全球变暖的不利影响在奶牛养殖中也日益明显。在奶牛公牛中，经常有报道称在夏季尤其是热带或亚热带条件下生育力较低。通常，减数分裂后发育阶段的精子对热应激更敏感。在此期间，组蛋白修饰和超乙酰化的广泛掺入使染色质转变为不稳定构象。这些不稳定形式的染色质被认为更容易受到热应激的影响，这可能会对精子的染色质凝聚产生影响。染色质凝聚改变的精子会扰乱父本原核中DNA甲基化重编程的动态过程，导致活性DNA去甲基化紊乱，随后出现从头甲基化模式。此外，用热应激精子使卵母细胞受精后，父本和母本原核的大小都有减小的趋势，导致受精率降低。在这篇综述中，我们将重点关注热应激诱导精子缺陷的机制，并对精子携带的表观遗传调控提供更详细的见解。
