Shepard T H, Muffley L A, Smith L T
School of Medicine, Department of Pediatrics, University of Washington, Seattle 98195-6320, USA.
Anat Rec. 1998 Nov;252(3):383-92. doi: 10.1002/(SICI)1097-0185(199811)252:3<383::AID-AR6>3.0.CO;2-Z.
Information on the morphology of mitochondria during embryogenesis is scattered in the literature but there appears to be a developmental pattern characterized by vesiculation of the mitochondrial cristae. During early organogenesis, the embryo is in a relative state of hypoxia and this is associated with decrease of terminal electron transport system activity and a marked increase in glycolysis. Ultrastructural studies of a 14 somite monkey embryo, and day 10 and 12 rat embryos, along with a review of the literature led us to determine that this hypoxic stage is characterized by vesiculation of the mitochondrial cristae. Starting in the late morula stage and continuing during early postimplantation embryogenesis the cristae increase and appear tubular or vesicular. After the end of neurulation, and with onset of vascular perfusion, the cristae gradually become lamellated and by the limb bud stage appear more mature. We suggest that new cristae form from blebs of the inner mitochondrial membrane and that subsequently with maturation these blebs collapse giving them a lamelliform appearance. The delamellated state of the cristae may protect the embryo from toxic respiratory end-products of oxidative respiration which could accumulate in an embryo lacking vascular perfusion. In the heart of monkey and rat embryos, the mitochondria had diameters which were approximately twice those found in skin and neural tube.
关于胚胎发生过程中线粒体形态的信息在文献中较为零散，但似乎存在一种以线粒体嵴形成小泡为特征的发育模式。在器官发生早期，胚胎处于相对缺氧状态，这与末端电子传递系统活性降低以及糖酵解显著增加有关。对一个14体节猴胚胎、第10天和第12天大鼠胚胎的超微结构研究，以及对文献的回顾，使我们确定这个缺氧阶段的特征是线粒体嵴形成小泡。从桑葚胚晚期开始并在植入后早期胚胎发生过程中持续，嵴增多并呈现管状或泡状。在神经胚形成结束后，随着血管灌注开始，嵴逐渐变为板层状，到肢芽期时显得更加成熟。我们认为新的嵴由线粒体内膜的小泡形成，随后随着成熟这些小泡塌陷，使其呈现板层状外观。嵴的板层状状态可能保护胚胎免受氧化呼吸产生的有毒呼吸终产物的影响，这些产物可能在缺乏血管灌注的胚胎中积累。在猴和大鼠胚胎的心脏中，线粒体的直径约为皮肤和神经管中线粒体直径的两倍。
