A Quantitative Electron Microscopic Analysis of the Membrana granulosa of Rat Preovulatory Follicles

Zoller, Lawrence C.

doi:10.1159/000145848

Cited by 10 publications

(4 citation statements)

References 14 publications

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“…Peripheral and perinuclear 10 μm regions were identified and demarcated on respective electron micrographs considering that a 1 cm distance on the electron micrograph represented a 1 μm distance within the oocyte (calculated from magnification achieved at printing the electron micrographs). The surface area density (surface area of organelle per unit volume of cytoplasm; μm 2 /μm 3 ), volume density (volume of organelle per unit volume of cytoplasm; μm 3 /μm 3 ) and numerical density (number of organelle per unit volume of cytoplasm; number/μm 3 ) were calculated for each organelle [ 17 , 18 ]. For simplicity, the volume density and numerical density of organelles is presented as percent and number/1000 μm 3 of oocyte volume.…”

Section: Methodsmentioning

confidence: 99%

Organelle reorganization in bovine oocytes during dominant follicle growth and regression

Dadarwal

Adams

Hyttel

et al. 2015

Reprod Biol Endocrinol

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BackgroundWe tested the hypothesis that organelles in bovine oocytes undergo changes in number and spatial distribution in a manner specific for phase of follicle development.MethodsCumulus-oocyte-complexes were collected from Hereford heifers by ultrasound-guided follicle aspiration from dominant follicles in the growing phase (n = 5; Day 0 = ovulation), static phase (n = 5), regressing phase (n = 7) of Wave 1 and from preovulatory follicles (n = 5). Oocytes were processed and transmission electron micrographs of ooplasm representing peripheral, perinuclear and central regions were evaluated using standard stereological methods.ResultsThe number of mitochondria and volume occupied by lipid droplets was higher (P < 0.03) in oocytes from regressing follicles (193.0 ± 10.4/1000 μm3 and 3.5 ± 0.7 %) than growing and preovulatory stages (118.7 ± 14.4/1000 μm3 and 1.1 ± 0.3 %; 150.5 ± 28.7/1000 μm3 and 1.6 ± 0.2 %, respectively). Oocytes from growing, static and preovulatory follicles had >70 % mitochondria in the peripheral regions whereas oocytes from regressing follicles had an even distribution. Oocytes from growing follicles had more lipid droplets in peripheral region than in central region (86.9 vs. 13.1 %). Percent surface area of mitochondria in contact with lipid droplets increased from growing (2.3 %) to static, regressing or preovulatory follicle stage (8.9, 6.1 and 6.2 %). The amount, size and distribution of other organelles did not differ among phases (P > 0.11).ConclusionsOur hypothesis was supported in that mitochondrial number increased and translocation occurred from a peripheral to an even distribution as follicles entered the regressing phase. In addition, lipid droplets underwent spatial reorganization from a peripheral to an even distribution during the growing phase and mitochondria-lipid contact area increased with follicle maturation.

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Section: Methodsmentioning

confidence: 99%

Organelle reorganization in bovine oocytes during dominant follicle growth and regression

Dadarwal

Adams

Hyttel

et al. 2015

Reprod Biol Endocrinol

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“…The distance between each adjacent cross-points on the grid provided an area of 0.25 μm 2 . The surface area density (surface area of organelle per unit volume of cytoplasm; μm 2 /μm 3 ), volume density (volume of organelle per unit volume of cytoplasm; μm 3 /μm 3 ) and/or numerical density (number of organelle per unit volume of cytoplasm; number/μm 3 ) were calculated for selected organelles [23,24]. For simplicity, the numerical density of organelles is presented as number/1000 μm 3 of oocyte volume.…”

Section: Analyses Of Cytoplasmic Organelle Parametersmentioning

confidence: 99%

Simulated physiological oocyte maturation has side effects on bovine oocytes and embryos

Razza

Pedersen

Stroebech³

et al. 2018

J Assist Reprod Genet

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Purpose Oocyte maturation is a complex process involving nuclear and cytoplasmic modulations, during which oocytes acquire their ability to become fertilized and support embryonic development. The oocyte is apparently Bprimed^for maturation during its development in the dominant follicle. As bovine oocytes immediately resume meiosis when cultured, it was hypothesized that delaying resumption of meiosis with cyclic nucleotide modulators before in vitro maturation (IVM) would allow the oocytes to acquire improved developmental competence. Methods We tested the Simulated Physiological Oocyte Maturation (SPOM) system that uses forskolin and 3-isobutyl-1methylxanthine for 2 h prior to IVM against two different systems of conventional IVM (Con-IVM). We evaluated the ultrastructure of matured oocytes and blastocysts and also assessed the expression of 96 genes related to embryo quality in the blastocysts. Results In summary, the SPOM system resulted in lower blastocyst rates than both Con-IVM systems (30 ± 9.1 vs. 35 ± 8.7; 29 ± 2.6 vs. 38 ± 2.8). Mature SPOM oocytes had significantly increased volume and number of vesicles, reduced volume and surface density of large smooth endoplasmic reticulum clusters, and lower number of mitochondria than Con-IVM oocytes. SPOM blastocysts showed only subtle differences with parallel undulations of adjacent trophectoderm plasma membranes and peripherally localized ribosomes in cells of the inner cell mass compared with Con-IVM blastocysts. SPOM blastocysts, however, displayed significant downregulation of genes related to embryonic developmental potential when compared to Con-IVM blastocysts. Conclusions Our results show that the use of the current version of the SPOM system may have adverse effects on oocytes and blastocysts calling for optimized protocols for improving oocyte competence.

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“…1982. 1983 and ultrastructure [Zoller. 1984b] the membrana granulosa of preovulatory follicles can be separated into three distinct regions: the peripheral region (the area adjacent to the basement membrane), the antral region and the corona radiata.…”

Section: Introductionmentioning

confidence: 99%

“…It is the cells of the peri pheral region which are most actively involved in follicular steroidogenesis [Richards. 1980], Compared to cells in the other regions those in the peripheral region contain more mitochondria, smooth endoplasmic reticulum and lipid droplets [Zoller, 1984b].…”

Section: Introductionmentioning

confidence: 99%

Effects of Daily Administration of Tetrahydrocannabinol on Rat Preovulatory Follicles

Zoller

Carr²

1988

Cells Tissues Organs

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Using morphometric techniques, we analyzed the effects of Δ⁹-tetrahydrocannabinol (THC) on the ultrastructure of rat preovulatory follicles. Rats were injected intraperitonally once daily with vehicle alone, or with vehicle plus THC on diestrus (D), metestrus (M) and diestrus (D), or on estrus (E), M and D. All animals were killed on proestrus. Nuclear, mitochondrial, lipid droplet and lysosomal volume density in the membrana granulosa were analyzed. There was no change in nuclear volume, but there were significantTHC-induced decreases in mitochondrial and lipid droplet volumes in the peripheral region of the granulosa. There were increases in dense-body volume in all regions of the granulosa from rats given THC either on D alone, or M and D. Dense-body volume returned to control levels in rats injected on E, M and D. It appears that THC can affect follicular ultrastructure and the effects change with the number of injections.

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A Quantitative Electron Microscopic Analysis of the Membrana granulosa of Rat Preovulatory Follicles

Cited by 10 publications

References 14 publications

Organelle reorganization in bovine oocytes during dominant follicle growth and regression

Organelle reorganization in bovine oocytes during dominant follicle growth and regression

Simulated physiological oocyte maturation has side effects on bovine oocytes and embryos

Effects of Daily Administration of Tetrahydrocannabinol on Rat Preovulatory Follicles

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