7.1 POJA- L1257+ 1258+1929. Electron microscopy of oocytes and interstitial cells, ovary (gerbil)
7.1 POJA- L1257+ 1258+1929
Title: Electron microscopy of oocytes and interstitial cells, ovary (gerbil)
Description: (A, B, C) Electron microscopy.
(A): Low magnification shows abundancy of lipid-loaded interstitial cells (luteinized theca cells) (1). At (2) tangential section of multilaminar secondary follicle surrounded by flattened theca cells.
(B): A primordial follicle with two electron-light ooplasms of two oocytes (3, 3a). (→) is border between oocytes; (*) in 3 indicates Balbiani body. Ooplasm of 3a shows decondensed chromatin in the germinal vesicle close to mitochondrial accumulation (4). Ooplasmic dense granules represent round cortical granules and lysosomal structures. Electron-dense and –light elongated nuclei of follicular cells (5) and between collagen fibers cuboidal nuclei (6) of theca cells with lipid droplets. Part of large foamy interstitial cell (luteinized theca cell) at (7).
(C): Higher magnification of germinal vesicle with more condensed chromatin. (→ Nuclear membrane). At (*) another Balbiani body with Golgi complex. Close to the slender follicular cell nucleus (5), luteinized theca cells (6) present themselves as lipid-loaded interstitial cells with tubular cristae.
Background: A Balbiani body has a heterogeneous morphology and composition among different species. Generally it is located near the nuclear membrane. It is a transient structure that consists of a.o. accumulation of mitochondria, Golgi areas, endoplasmic reticulum, lipids, fibro granular material, RNAs. It is thought to function in the organization and transport of organelles and RNAs to specific regions of the ooplasm. The cortical granules from the Golgi areas migrate to the periphery of the oocyte fuse with the oolemma. After sperm-oocyte fusion the granule content (proteases) is discharged in the zona pellucida resulting in a transformation of the pellucidal structure that penetration by other capacitated spermatozoa is prevented (so-called zona reaction). It is well-know that in rabbit, guinea pig, gerbil, ferret and cat groups of lipid-containing cells form the primary interstitial tissue in the whole ovarian stroma while preantral follicles are still very small. Secondary interstitial tissue develops a few weeks later when the follicles grow and subsequently become atretic. The primary interstitial tissue then becomes less conspicuous. In numerous atretic follicles granulosa cells degenerate completely and transform into a lipid mass that is phagocytized. This phenomenon is accompanied by enlargement of epithelioid thecal cells becoming ‘luteinized’ with lipid inclusions in a glandular arrangement. They give rise to the glandular cell masses which contribute to the bulk of interstitial tissue in adult ovaries. At first there is a gradual build-up of secondary interstitial tissue from atretic follicles and degenerated granulosa cells. But after a few months of age the theca cells actively develop into lipid-containing glandular interstitial cells and the process continues throughout life as follicles become atretic.
Keywords/Mesh: female reproductive organs, Balbiani body, ovarian follicle, oocyte, interstitial cells, ovary, histology, POJA collection
Title: Electron microscopy of oocytes and interstitial cells, ovary (gerbil)
Description: (A, B, C) Electron microscopy.
(A): Low magnification shows abundancy of lipid-loaded interstitial cells (luteinized theca cells) (1). At (2) tangential section of multilaminar secondary follicle surrounded by flattened theca cells.
(B): A primordial follicle with two electron-light ooplasms of two oocytes (3, 3a). (→) is border between oocytes; (*) in 3 indicates Balbiani body. Ooplasm of 3a shows decondensed chromatin in the germinal vesicle close to mitochondrial accumulation (4). Ooplasmic dense granules represent round cortical granules and lysosomal structures. Electron-dense and –light elongated nuclei of follicular cells (5) and between collagen fibers cuboidal nuclei (6) of theca cells with lipid droplets. Part of large foamy interstitial cell (luteinized theca cell) at (7).
(C): Higher magnification of germinal vesicle with more condensed chromatin. (→ Nuclear membrane). At (*) another Balbiani body with Golgi complex. Close to the slender follicular cell nucleus (5), luteinized theca cells (6) present themselves as lipid-loaded interstitial cells with tubular cristae.
Background: A Balbiani body has a heterogeneous morphology and composition among different species. Generally it is located near the nuclear membrane. It is a transient structure that consists of a.o. accumulation of mitochondria, Golgi areas, endoplasmic reticulum, lipids, fibro granular material, RNAs. It is thought to function in the organization and transport of organelles and RNAs to specific regions of the ooplasm. The cortical granules from the Golgi areas migrate to the periphery of the oocyte fuse with the oolemma. After sperm-oocyte fusion the granule content (proteases) is discharged in the zona pellucida resulting in a transformation of the pellucidal structure that penetration by other capacitated spermatozoa is prevented (so-called zona reaction). It is well-know that in rabbit, guinea pig, gerbil, ferret and cat groups of lipid-containing cells form the primary interstitial tissue in the whole ovarian stroma while preantral follicles are still very small. Secondary interstitial tissue develops a few weeks later when the follicles grow and subsequently become atretic. The primary interstitial tissue then becomes less conspicuous. In numerous atretic follicles granulosa cells degenerate completely and transform into a lipid mass that is phagocytized. This phenomenon is accompanied by enlargement of epithelioid thecal cells becoming ‘luteinized’ with lipid inclusions in a glandular arrangement. They give rise to the glandular cell masses which contribute to the bulk of interstitial tissue in adult ovaries. At first there is a gradual build-up of secondary interstitial tissue from atretic follicles and degenerated granulosa cells. But after a few months of age the theca cells actively develop into lipid-containing glandular interstitial cells and the process continues throughout life as follicles become atretic.
Keywords/Mesh: female reproductive organs, Balbiani body, ovarian follicle, oocyte, interstitial cells, ovary, histology, POJA collection