Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan.
Livestock Research Institute, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Oita, Japan.
Anim Sci J. 2020 Jan-Dec;91(1):e13493. doi: 10.1111/asj.13493.
Although successful fertilization is completed by only 150 sperm in the pig oviduct, more than 50,000 sperms are required to achieve a fertilization rate of more than 70% by pig in vitro fertilization (IVF). In this study, to improve the efficiency of pig IVF, the effects of hypoxic conditions and treatment with creatine and methyl-beta cyclodextrin (MβCD) on the glycolytic pathway were investigated. Under low O conditions, zig-zag motility was strongly induced within 30 min; however, the induction disappeared at 60 min. Although caffeine suppressed zig-zag motility under low O conditions, creatine induced and sustained zig-zag motility until 120 min. Additionally, pretreatment with MβCD for 15 min greatly enhanced zig-zag motility via ATP production in sperm incubated with creatine under low O conditions. Sperm pretreated with MβCD were used for IVF in medium containing creatine under low O conditions. A fertilization rate of approximately 70% was achieved with only 1.0 x 10 sperms/mL, and there were few polyspermic embryos. Therefore, our novel method was beneficial for efficient production of pig embryos in vitro. Moreover, the zig-zag motility may be a novel movement which boar capacitated sperm exhibit in the culture medium.
虽然在猪输卵管中只有 150 个精子就能完成受精，但猪体外受精（IVF）要达到 70%以上的受精率则需要超过 50000 个精子。在这项研究中，为了提高猪 IVF 的效率，研究了缺氧条件以及肌酸和甲基-β环糊精（MβCD）处理对糖酵解途径的影响。在低氧条件下，Zig-zag 运动在 30 分钟内被强烈诱导；然而，这种诱导在 60 分钟时消失。虽然咖啡因能抑制低氧条件下的 Zig-zag 运动，但肌酸能诱导并维持 Zig-zag 运动，直到 120 分钟。此外，MβCD 预处理 15 分钟能极大地增强在低氧条件下用肌酸孵育的精子中的 Zig-zag 运动，通过产生 ATP。用 MβCD 预处理的精子在低氧条件下的含有肌酸的培养基中进行 IVF。仅用 1.0 x 10 个精子/ml 就可达到约 70%的受精率，且多精受精胚胎较少。因此，我们的新方法有利于高效生产猪胚胎。此外，Zig-zag 运动可能是公猪精子在培养介质中表现出的一种新的运动。
