Nottola Stefania A, Makabe Sayoko, Stallone Tiziana, Familiari Giuseppe, Correr Silvia, Macchiarelli Guido
Department of Human Anatomy, University of Rome La Sapienza, Rome, Italy.
Arch Histol Cytol. 2005 Jun;68(2):133-41. doi: 10.1679/aohc.68.133.
Human zona pellucida (ZP) is maintained up to the blastocyst stage prior to hatching. In in vitro fertilized (IVF) embryos, it eventually acts as a morphodynamic interface between the cultured embryo and its microenvironment. Ultrastructural data on the ZP of IVF blastocysts are scarce in humans. We employed correlated phase contrast microscopy (PCM) and scanning electron microscopy (SEM) to study retrospectively the ultrastructural morphology of the ZP outer surface of 20 IVF human blastocysts from 16 Japanese patients (28-44 years of age, average 36.7+/-4.2) with a history of infertility. Blastocysts were derived from conventional in vitro fertilization (cIVF) (n = 10) and from intracytoplasmic sperm injection (ICSI) (n = 10). Both cIVF and ICSI groups included "clear blastocysts" (n = 5) and "dark blastocysts" (n = 5). By PCM, the clear blastocysts exhibited a regular, round-shaped contour and consisted of clear and voluminous cells. By SEM, they displayed a spongy ZP with numerous fenestrations formed by networked filaments. By PCM, dark blastocysts appeared irregularly shaped and often collapsed, and comprised dark cells and debris. By SEM, their ZP were smooth with remnants of compact fenestrations. In conclusion, viable blastocysts presented a normal ZP outer surface ultrastructure, whereas unhealthy blastocysts showed an altered ZP outer surface, comparable to that of immature/atretic oocytes. Such alterations could reflect sub-optimal culture conditions and/or could be related to blastocyst degenerative processes. The blastocyst ZP surface ultrastructure was unaffected by the fertilization technique (cIVF or ICSI). These data suggest that blastocyst survival in vitro is related to ZP ultrastructure maintenance.
人类透明带（ZP）在孵化前一直维持到囊胚阶段。在体外受精（IVF）胚胎中，它最终成为培养胚胎与其微环境之间的形态动力学界面。关于人类IVF囊胚透明带的超微结构数据很少。我们采用相关相差显微镜（PCM）和扫描电子显微镜（SEM），对16名日本患者（年龄28 - 44岁，平均36.7±4.2岁）有不孕史的20个IVF人类囊胚的透明带外表面超微结构形态进行回顾性研究。囊胚来自常规体外受精（cIVF）（n = 10）和卵胞浆内单精子注射（ICSI）（n = 10）。cIVF组和ICSI组均包括“清亮囊胚”（n = 5）和“灰暗囊胚”（n = 5）。通过PCM观察，清亮囊胚呈现规则的圆形轮廓，由清亮且体积较大的细胞组成。通过SEM观察，它们的透明带呈海绵状，有许多由网络状细丝形成的小孔。通过PCM观察，灰暗囊胚形状不规则且常塌陷，由深色细胞和碎片组成。通过SEM观察，它们的透明带光滑，有紧密小孔的残余。总之，有活力的囊胚呈现正常的透明带外表面超微结构，而不健康的囊胚显示透明带外表面改变，类似于未成熟/闭锁卵母细胞的情况。这种改变可能反映了次优的培养条件和/或可能与囊胚退化过程有关。囊胚透明带表面超微结构不受受精技术（cIVF或ICSI）的影响。这些数据表明体外囊胚存活与透明带超微结构维持有关。
