Irving-Rodgers Helen F, Krupa Malgorzata, Rodgers Raymond J
Reproductive Medicine Unit, Department of Obstetrics and Gynaecology, University of Adelaide, Adelaide, South Australia 5005, Australia.
Biol Reprod. 2003 Dec;69(6):2022-8. doi: 10.1095/biolreprod.103.017442. Epub 2003 Aug 20.
Bovine ovarian antral follicles exhibit either one or the other of two patterns of granulosa cell death in atresia. Death can commence either from the antrum and progress toward the basal lamina (antral atresia) or the converse (basal atresia). In basal atresia, the remaining live antrally situated cells appeared to continue maturing. Beyond that, little is known about these distinct patterns of atresia. Healthy (nonatretic) follicles also exhibit either one or the other of two patterns of granulosa cell shape, follicular basal lamina ultrastructure or location of younger cells within the membrana granulosa. To examine these different phenotypes, the expression of the steroidogenic enzymes cholesterol side-chain cleavage cytochrome P450 (SCC) and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in granulosa cells and concentrations of steroid hormones in follicular fluid were measured in individual histologically classified bovine antral follicles. Healthy follicles first expressed SCC and 3beta-HSD in granulosa cells only when the follicles reached an approximate threshold of 10 mm in diameter. The pattern of expression in antral atretic follicles was the same as healthy follicles. Basal atretic follicles were all <5 mm. In these, the surviving antral granulosa cells expressed SCC and 3beta-HSD. In examining follicles of 3-5 mm, basal atretic follicles were found to have substantially elevated progesterone (P < 0.001) and decreased androstenedione and testosterone compared to healthy and antral atretic follicles. Estradiol was highest in the large healthy follicles, lower in the small healthy follicles, lower still in the antral atretic follicles, and lowest in the basal atretic follicles. Our findings have two major implications. First, the traditional method of identifying atretic follicles by measurement of steroid hormone concentrations may be less valid with small bovine follicles. Second, features of the two forms of follicular atresia are so different as to imply different mechanisms of initiation and regulation.
牛卵巢窦状卵泡闭锁时，颗粒细胞死亡呈现两种模式中的一种。细胞死亡可从卵泡腔开始并向基膜发展（卵泡腔闭锁），或者相反（基底闭锁）。在基底闭锁中，剩余存活的位于卵泡腔的细胞似乎继续成熟。除此之外，对于这些不同的闭锁模式知之甚少。健康（非闭锁）卵泡在颗粒细胞形状、卵泡基膜超微结构或颗粒膜内较年轻细胞的位置方面也呈现两种模式中的一种。为了研究这些不同的表型，在组织学分类的单个牛窦状卵泡中，测量了颗粒细胞中类固醇生成酶胆固醇侧链裂解细胞色素P450（SCC）和3β-羟基类固醇脱氢酶（3β-HSD）的表达以及卵泡液中类固醇激素的浓度。健康卵泡仅在直径达到约10毫米的近似阈值时，颗粒细胞才首次表达SCC和3β-HSD。卵泡腔闭锁卵泡中的表达模式与健康卵泡相同。基底闭锁卵泡均小于5毫米。在这些卵泡中，存活的卵泡腔颗粒细胞表达SCC和3β-HSD。在检查3 - 5毫米的卵泡时，发现基底闭锁卵泡与健康卵泡和卵泡腔闭锁卵泡相比，孕酮显著升高（P < 0.001），雄烯二酮和睾酮降低。雌二醇在大的健康卵泡中最高，在小的健康卵泡中较低，在卵泡腔闭锁卵泡中更低，在基底闭锁卵泡中最低。我们的发现有两个主要意义。第一，通过测量类固醇激素浓度来识别闭锁卵泡的传统方法对于小牛卵泡可能不太有效。第二，两种卵泡闭锁形式的特征差异很大，这意味着起始和调节机制不同。
