Familiari Giuseppe, Heyn Rosemarie, Relucenti Michela, Nottola Stefania A, Sathananthan A Henry
Laboratory of Electron Microscopy, Pietro M. Motta Department of Anatomy, University of Rome, La Sapienza, 00161 Rome, Italy.
Int Rev Cytol. 2006;249:53-141. doi: 10.1016/S0074-7696(06)49002-1.
This study describes the updated, fine structure of human gametes, the human fertilization process, and human embryos, mainly derived from assisted reproductive technology (ART). As clearly shown, the ultrastructure of human reproduction is a peculiar multistep process, which differs in part from that of other mammalian models, having some unique features. Particular attention has been devoted to the (1) sperm ultrastructure, likely "Tygerberg (Kruger) strict morphology criteria"; (2) mature oocyte, in which the MII spindle is barrel shaped, anastral, and lacking centrioles; (3) three-dimensional microarchitecture of the zona pellucida with its unique supramolecular filamentous organization; (4) sperm-egg interactions with the peculiarity of the sperm centrosome that activates the egg and organizes the sperm aster and mitotic spindles of the embryo; and (5) presence of viable cumulus cells whose metabolic activity is closely related to egg and embryo behavior in in vitro as well as in vivo conditions, in a sort of extraovarian "microfollicular unit." Even if the ultrastructural morphodynamic features of human fertilization are well understood, our knowledge about in vivo fertilization is still very limited and the complex sequence of in vivo biological steps involved in human reproduction is only partially reproduced in current ART procedures.
本研究描述了主要源自辅助生殖技术（ART）的人类配子、人类受精过程及人类胚胎的最新精细结构。如图所示，人类生殖的超微结构是一个独特的多步骤过程，部分不同于其他哺乳动物模型，具有一些独特特征。特别关注了以下方面：（1）精子超微结构，可能符合“泰格堡（克鲁格）严格形态学标准”；（2）成熟卵母细胞，其中减数第二次分裂纺锤体呈桶状、无星状体且缺乏中心粒；（3）透明带的三维微结构及其独特的超分子丝状组织；（4）精卵相互作用，其特点是精子中心体激活卵子并组织胚胎的精子星体和有丝分裂纺锤体；（5）存在有活力的卵丘细胞，其代谢活性在体外及体内条件下均与卵子和胚胎行为密切相关，形成一种卵巢外的“微卵泡单位”。即使人类受精的超微结构形态动力学特征已得到充分理解，但我们对体内受精的了解仍然非常有限，当前ART程序仅部分再现了人类生殖中涉及的体内生物学步骤的复杂序列。
