Silva J R, Báo S N, Lucci C M, Carvalho F C, Andrade E R, Ferreira M A, Figueiredo J R
Laboratory of Manipulation of Oocytes Enclosed in Preantral Follicles - LAMOFOPA, Faculty of Veterinary, University of Ceará, CE, Fortaleza, Brazil.
Anim Reprod Sci. 2001 May 31;66(3-4):209-23. doi: 10.1016/s0378-4320(01)00102-6.
The present work has investigated the morphological and ultrastructural changes occurring during degeneration of goat preantral follicles preserved in vitro and showed quantitative data about the distribution of follicular degeneration types in the control and after preservation in coconut water solution or Braun-Collins solution at different temperatures (4, 20 or 39 degrees C) and incubation times (4, 12 or 24h). At the slaughterhouse, the pair of ovaries of each animal was divided into 19 fragments. One ovarian fragment was immediately fixed (control: Time 0). The other 18 fragments were randomly distributed in tubes containing 2ml of coconut water or Braun-Collins solution at 4, 20 or 39 degrees C and stored for 4, 12 or 24h. Normal preantral follicles exhibited a healthy oocyte surrounded by one or more well-organized layers of granulosa cells. The ooplasm contained numerous rounded or elongated mitochondria with continuous mitochondrial membranes. Golgi complexes were rare. Both smooth and rough endoplasmic reticulum were observed, either as isolated aggregations or complex associations with mitochondria and vesicles. Degenerated preantral follicles in the control tissue exhibited pycnotic nuclei of the oocyte, vacuolated ooplasm and normal granulosa cells. This kind of degeneration also predominated significantly (P<0.05) after preservation at 4 degrees C. In contrast, after preservation at 20 or 39 degrees C a significant predominance (P<0.05) of preantral follicles showing a retracted oocyte and swollen granulosa cells was observed. These follicles showed large irregularity of the oocyte and nuclear outlines. The ooplasm exhibited moderate proliferation of the endoplasmic reticulum and mitochondria showed disappearance of most of the cristae and damage to the mitochondrial membrane. Some follicles had numerous vacuoles in the ooplasm. Granulosa cells were spread and a low density of organelles was observed. The alterations in follicular structure progressed with an increase of temperature from 20 to 39 degrees C as well as with an increase of the incubation time from 4 to 12, or 24h. In conclusion, the present study shows for the first time that initial proliferation of the endoplasmic reticulum and damage to mitochondria are the first signs of degeneration in goat preantral follicles during storage in vitro.
本研究调查了体外保存的山羊腔前卵泡在退化过程中发生的形态学和超微结构变化，并给出了对照以及在不同温度（4、20或39摄氏度）和孵育时间（4、12或24小时）下保存在椰子水溶液或布劳恩 - 柯林斯溶液中的卵泡退化类型分布的定量数据。在屠宰场，将每只动物的一对卵巢分成19个片段。一个卵巢片段立即固定（对照：时间0）。其他18个片段随机分布在含有2毫升椰子水或布劳恩 - 柯林斯溶液的试管中，在4、20或39摄氏度下保存4、12或24小时。正常的腔前卵泡表现为健康的卵母细胞被一层或多层组织良好的颗粒细胞包围。卵质中含有许多圆形或细长的线粒体，线粒体膜连续。高尔基体复合体很少见。观察到光滑内质网和粗面内质网，它们要么作为孤立的聚集体，要么与线粒体和囊泡形成复杂的关联。对照组织中退化的腔前卵泡表现为卵母细胞核固缩、卵质空泡化和颗粒细胞正常。在4摄氏度保存后，这种退化类型也占显著优势（P<0.05）。相反，在20或39摄氏度保存后，观察到腔前卵泡出现显著优势（P<0.05），表现为卵母细胞收缩和颗粒细胞肿胀。这些卵泡的卵母细胞和核轮廓表现出很大的不规则性。卵质中内质网中度增殖，线粒体的嵴大部分消失，线粒体膜受损。一些卵泡的卵质中有许多空泡。颗粒细胞散开，细胞器密度较低。随着温度从20摄氏度升高到39摄氏度以及孵育时间从4小时增加到12或24小时，卵泡结构的改变逐渐加重。总之，本研究首次表明内质网的初始增殖和线粒体损伤是山羊腔前卵泡体外保存期间退化的最初迹象。
