Funahashi H, Day B N
Faculty of Agriculture, Okayama University, Japan.
J Reprod Fertil Suppl. 1997;52:271-83.
A series of integrated, effective techniques is required to produce pig embryos from follicular oocytes in vitro. The failure to form a male pronucleus and polyspermy have been serious problems in efforts to produce embryos efficiently in vitro from pig oocytes. The former problem is now considered to be due to oxidative stress and the latter has been partially solved by reducing the number of capacitated spermatozoa reaching the oocytes. By the use of new technology for in vitro production of embryos, an acceptable rate of blastocyst formation and the birth of live piglets has been achieved. However, even with the use of these improved in vitro maturation (IVM) and fertilization (IVF) conditions, the efficiency of production of in vitro blastocysts and offspring still remains relatively low. More recently the developmental competence of embryos matured and fertilized in vitro has been investigated through modification of culture conditions of oocytes during the germinal vesicle stage. Oocyte competence for early embryonic development appears to be achieved by active communication between the oocyte and follicular cells. Since the ovarian oocytes available for IVM are primarily those present in mid-size antral follicles of prepubertal gilts, more research is needed to gain an improved understanding of the culture conditions required to induce developmental competence in oocytes from both preantral and antral follicles as well as additional modifications in IVF systems to overcome the problem of polyspermic penetration.
要从卵泡卵母细胞体外生产猪胚胎，需要一系列综合有效的技术。在从猪卵母细胞高效体外生产胚胎的过程中，雄性原核未形成和多精受精一直是严重问题。前一个问题现在被认为是由于氧化应激，而后一个问题通过减少到达卵母细胞的获能精子数量已得到部分解决。通过使用胚胎体外生产的新技术，已实现了可接受的囊胚形成率和活仔猪的出生。然而，即使使用这些改进的体外成熟（IVM）和受精（IVF）条件，体外囊胚和后代的生产效率仍然相对较低。最近，通过改变生发泡期卵母细胞的培养条件，对体外成熟和受精胚胎的发育能力进行了研究。卵母细胞早期胚胎发育的能力似乎是通过卵母细胞与卵泡细胞之间的活跃通讯来实现的。由于可用于IVM的卵巢卵母细胞主要是青春期前后备母猪中等大小窦状卵泡中的卵母细胞，因此需要更多研究来更好地了解诱导来自窦前卵泡和窦状卵泡的卵母细胞发育能力所需的培养条件，以及IVF系统中的其他改进措施，以克服多精穿透问题。
