Elshafie Mona A A, Fouad Ghada M M, Shaaban Mohammed M, Helmi Amal M, Ewies Ayman A A
Faculty of Medicine, University of Alexandria, Alexandria, Egypt.
Gynecol Endocrinol. 2008 Feb;24(2):67-78. doi: 10.1080/09513590701705312.
Leptin serves as a signal to the central nervous system with information on the critical amount of adipose tissue stores that is necessary for activation of the hypothalamic-pituitary-ovarian axis.
To document the histological and ultrastructural changes that occur in the ovarian follicles of immature albino rats treated with leptin when compared with controls. Furthermore, the endometrial histological and immunohistochemical, and vaginal cytological changes suggestive of ovulation were assessed.
The study was carried out on 50 immature female albino rats aged 22 days; 24 of them were injected with 5 microg leptin daily and 26 rats were taken as controls. Vaginal smears were taken daily, three animals were sacrificed every 2-4 days from each group, ovaries and uteri were dissected and specimens were prepared for electron microscopic, histological and/or immunohistochemical assessment. The research project was approved by The Histology Department Committee of Alexandria Medical School, which is licensed for animal care and use.
Electron microscopic and histological examination confirmed the occurrence of maturational changes in various ovarian components from 26 days of age in leptin-treated rats, with ovulation occurring from the age of 30 days. The granulosa, theca and stroma cells showed signs of steroidogenesis, with increased mitosis within granulosa cells. The ooplasm showed an increased number of organelles, and annulate lamellae were demonstrated. The zona pellucida revealed microvilli, adhering junctions and gap junctions. Similarly, the endometrial histological and vaginal cytological maturational changes were detected in leptin-treated rats from 26 days of age. Furthermore, there was high expression of estrogen receptor-alpha in almost all columnar and stroma cells of the endometrium. However, the control rats ovulated around the normal age of maturation, i.e. 42 days.
We documented ultrastructural, histological, immunohistochemical and cytological evidence that leptin accelerates the onset of puberty in female albino rats. The potential role of exogenous leptin, in cases of impaired reproductive function in humans, needs to be elucidated.
瘦素作为一种向中枢神经系统传递信号的物质，携带着关于激活下丘脑 - 垂体 - 卵巢轴所需的关键脂肪组织储存量的信息。
记录与对照组相比，用瘦素处理的未成熟白化大鼠卵巢卵泡中发生的组织学和超微结构变化。此外，评估提示排卵的子宫内膜组织学、免疫组织化学以及阴道细胞学变化。
该研究对50只22日龄的未成熟雌性白化大鼠进行；其中24只每天注射5微克瘦素，26只大鼠作为对照。每天采集阴道涂片，每组每2 - 4天处死3只动物，解剖卵巢和子宫，制备标本用于电子显微镜、组织学和/或免疫组织化学评估。该研究项目获得了亚历山大医学院组织学系委员会的批准，该委员会持有动物护理和使用许可证。
电子显微镜和组织学检查证实，在瘦素处理的大鼠中，从26日龄起各种卵巢成分出现成熟变化，30日龄开始排卵。颗粒细胞、卵泡膜细胞和基质细胞显示出类固醇生成的迹象，颗粒细胞内有丝分裂增加。卵质中细胞器数量增加，并可见环层板。透明带显示有微绒毛、黏附连接和缝隙连接。同样，在26日龄的瘦素处理大鼠中检测到子宫内膜组织学和阴道细胞学成熟变化。此外，子宫内膜几乎所有柱状细胞和基质细胞中雌激素受体α表达较高。然而，对照大鼠在正常成熟年龄左右，即42日龄时排卵。
我们记录了超微结构、组织学、免疫组织化学和细胞学证据，表明瘦素可加速雌性白化大鼠青春期的开始。外源性瘦素在人类生殖功能受损情况下的潜在作用有待阐明。
