Hexachlorobenzene toxicity in the rat ovary: II. Ultrastructure induced by medium (10 mg/kg) dose exposure

Amreek Singh; Warren G. Foster; Anna Dykeman; David C. Villeneuve

doi:10.1017/s042482010012374x

Hexachlorobenzene toxicity in the rat ovary: II. Ultrastructure induced by medium (10 mg/kg) dose exposure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012374x ◽

1992 ◽

Vol 50 (1) ◽

pp. 668-669

Author(s):

Amreek Singh ◽

Warren G. Foster ◽

Anna Dykeman ◽

David C. Villeneuve

Keyword(s):

Germ Cells ◽

Primordial Germ Cells ◽

Surface Epithelium ◽

Morphological Parameters ◽

Comprehensive Investigation ◽

Ovary Surface Epithelium ◽

Rat Ovary ◽

High Doses

Hexachlorobenzene (HCB) is a known toxicant that is found in the environment as a by-product during manufacture of certain pesticides. This chlorinated chemical has been isolated from many tissues including ovary. When administered in high doses, HCB causes degeneration of primordial germ cells and ovary surface epithelium in sub-human primates. A purpose of this experiment was to determine a no-effect dose of the chemical on the rat ovary. The study is part of a comprehensive investigation on the effects of the compound on the biochemical, hematological, and morphological parameters in the monkey and rat.

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46 Morphologic and functional characterization of the early fetal equine gonads

Reproduction Fertility and Development ◽

10.1071/rdv31n1ab46 ◽

2019 ◽

Vol 31 (1) ◽

pp. 149

Author(s):

D. Scarlet ◽

I. Walter ◽

S. Handschuh ◽

R. Ellerbrock ◽

I. Canisso ◽

...

Keyword(s):

Germ Cells ◽

Primordial Germ Cells ◽

Functional Characterization ◽

Basal Membrane ◽

Interstitial Cells ◽

Germinal Epithelium ◽

Surface Epithelium ◽

Seminiferous Tubules ◽

Stem Cell Markers ◽

And Function

In the equine embryo, putative primordial germ cells appear between 20 and 30 days and the gonadal primordium can first be identified at Day 30 after ovulation, respectively. Subsequently, sexual differentiation of the gonad occurs and completes by Day 45 of pregnancy. The objectives of this work were to describe the morphology and function of the fetal equine ovary and testis at the beginning of the fetal stage of pregnancy. For this purpose, 12 equine fetuses (6 males and 6 females) were collected at 45 days (n=1, female), 50 days (n=1, male), and 60 days (n=10, 5 males and 5 females) after ovulation, respectively. A high attention was given to Day 60 because it is the representative time for fetal sex determination in horses by transrectal ultrasonography. Conceptuses were collected transcervically by uterine lavage and fixed in 4% formaldehyde before being prepared for morphology analysis and immunohistochemistry assay. Gonads were identified and immunostained for anti-Müllerian hormone (AMH), Ki67, CD117, LIN28, vimentin, cytokeratin, and laminin. In all fetuses, gonads were situated in a sublumbar localisation and connected with the mesonephros. In females, primordial germ cells were localised close to the surface germinal epithelium, whereas in males the primordial germ cells were organised in cord-like clusters-the future seminiferous tubules. At this stage, interstitial cells predominate in the testes. The AMH staining was strongly expressed in the fetal testis, but was completely absent from the fetal ovary. Protein expression of mitosis marker Ki67 was localised in primordial germ cells of both sexes. Moreover, stem cell markers LIN28 and CD117 were also present in the gonads. In females, these proteins were not only localised in some of the primordial germ cells, but also in the surface germinal epithelium, whereas in males LIN28 and CD117 were immunolocalized in the seminiferous tubules, distant from the surface epithelium. Vimentin was strongly expressed in the interstitial cells of the gonads of both sexes. Using laminin staining, basal membrane of the seminiferous tubules in males and of primordial germ cells in females could be visualised. In females, the basal membrane of primordial germ cells also stained positive for cytokeratin, whereas in males no cytokeratin staining was seen around seminiferous tubules. Moreover, the surface germinal epithelium of both sexes stained positive for cytokeratin. This study widely extends existing knowledge about morphology, development, and function of the early fetal equine gonad. Presence of stem cells could be clearly demonstrated in the gonads of both sexes, whereas AMH staining clearly distinguished between males and females, confirming the important role of this hormone for gonadal and reproductive tract differentiation.

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Novel Action of FSH on Stem Cells in Adult Mammalian Ovary Induces Postnatal Oogenesis and Primordial Follicle Assembly

Stem Cells International ◽

10.1155/2016/5096596 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 9

Author(s):

Deepa Bhartiya ◽

Seema Parte ◽

Hiren Patel ◽

Kalpana Sriraman ◽

Kusum Zaveri ◽

...

Keyword(s):

Stem Cells ◽

Primordial Germ Cells ◽

Primordial Follicle ◽

Reproductive Period ◽

Surface Epithelium ◽

Alternative Source ◽

Self Renewal ◽

Premature Failure ◽

Ovary Surface Epithelium

Adult mammalian ovary has been under the scanner for more than a decade now since it was proposed to harbor stem cells that undergo postnatal oogenesis during reproductive period like spermatogenesis in testis. Stem cells are located in the ovary surface epithelium and exist in adult and menopausal ovary as well as in ovary with premature failure. Stem cells comprise two distinct populations including spherical, very small embryonic-like stem cells (VSELs which express nuclear OCT-4 and other pluripotent and primordial germ cells specific markers) and slightly bigger ovarian germ stem cells (OGSCs with cytoplasmic OCT-4 which are equivalent to spermatogonial stem cells in the testes). These stem cells have the ability to spontaneously differentiate into oocyte-like structuresin vitroand on exposure to a younger healthy niche. Bone marrow may be an alternative source of these stem cells. The stem cells express FSHR and respond to FSH by undergoing self-renewal, clonal expansion, and initiating neo-oogenesis and primordial follicle assembly. VSELs are relatively quiescent and were recently reported to survive chemotherapy and initiate oogenesis in mice when exposed to FSH. This emerging understanding and further research in the field will help evolving novel strategies to manage ovarian pathologies and also towards oncofertility.

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