Structural changes in bovine oocytes during final maturation in vivo

Kruip, Th.A.M.; Cran, D. G.; Beneden, Th.H. van; Dieleman, S.J.

doi:10.1002/mrd.1120080105

Cited by 236 publications

(148 citation statements)

References 42 publications

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“…In addition, bovine oocytes showed large aggregates of SER surrounded by mitochondria after 48 h of culture (Hyttel et al, 1986). Kruip et al (1983) suggesting the existence of metabolic units in which vesicles and mitochondria are combined via the SER. Thus, the clustering of organelles appears to indicate a decrease in oocyte metabolism during culture (Hyttel et al, 1986).…”

Section: Discussionmentioning

confidence: 99%

Morphological and ultrastructural changes occurring during degeneration of goat preantral follicles preserved in vitro

Silva

Báo

Lucci

et al. 2001

Animal Reproduction Science

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The present work has investigated the morphological and ultrastructural changes occurring during degeneration of goat preantral follicles preserved in vitro and showed quantitative data about the distribution of follicular degeneration types in the control and after preservation in coconut water solution or Braun-Collins solution at different temperatures (4, 20 or 39°C) and incubation times (4, 12 or 24 h). At the slaughterhouse, the pair of ovaries of each animal was divided into 19 fragments. One ovarian fragment was immediately fixed (control: Time 0). The other 18 fragments were randomly distributed in tubes containing 2 ml of coconut water or Braun-Collins solution at 4, 20 or 39°C and stored for 4, 12 or 24 h. Normal preantral follicles exhibited a healthy oocyte surrounded by one or more well-organized layers of granulosa cells. The ooplasm contained numerous rounded or elongated mitochondria with continuous mitochondrial membranes. Golgi complexes were rare. Both smooth and rough endoplasmic reticulum were observed, either as isolated aggregations or complex associations with mitochondria and vesicles. Degenerated preantral follicles in the control tissue exhibited pycnotic nuclei of the oocyte, vacuolated ooplasm and normal granulosa cells. This kind of degeneration also predominated significantly (P<0.05) after preservation at 4°C. In contrast, after preservation at 20 or 39°C a significant predominance (P<0.05) of preantral follicles showing a retracted oocyte and swollen granulosa cells was observed. These follicles showed large irregularity of the oocyte and nuclear outlines. The ooplasm exhibited moderate proliferation of the endoplasmic reticulum and mitochondria showed disappearance of most of the cristae and damage to the mitochondrial membrane. Some follicles had numerous vacuoles in the ooplasm. Granulosa cells were spread and a low density of organelles was observed. The alterations in follicular structure progressed with an increase of temperature from 20 to 39°C as well as with an increase of the incubation time from 4 to 12, or 24 h. In conclusion, the present study shows for the first time that initial proliferation of the endoplasmic reticulum and damage to mitochondria are the first signs of degeneration in goat preantral follicles during storage in vitro.

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Section: Discussionmentioning

confidence: 99%

Morphological and ultrastructural changes occurring during degeneration of goat preantral follicles preserved in vitro

Silva

Báo

Lucci

et al. 2001

Animal Reproduction Science

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“…Cortical granules are distributed throughout the entire inner surface of the sphere of the oocyte during final maturation [10,17]. Exocytosis of cortical granules is the most common mechanism for the prevention of polyspermy.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Fertilization and Cortical Granule Distribution of Bovine Oocytes Having Heterogeneous Ooplasm with Dark Clusters.

Nagano

Takahashi

Katagiri

1999

The Journal of Veterinary Medical Science

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ABSTRACT. In vitro maturation, fertilization and subsequent development of oocytes with homogeneous (category 1), or heterogeneous ooplasm (category 2) were investigated. No significant differences were observed in the nuclear maturation and total fertilization rates between the two categories. However, category 2 oocytes showed a higher normal fertilization rate due to their lower incidence of polyspermy as compared to category 1 oocytes. Electron microscopic study revealed that all category 2 oocytes had cortical granules lined up next to the plasma membrane, and that some category 1 oocytes still had small clusters of cortical granules after maturation. Although the proportion of cleaved zygotes was higher in category 2, the percentages of cleaved zygotes that developed to the blastocyst stage did not differ between the two categories. These results demonstrate that oocytes with heterogeneous ooplasm have a higher capacity for normal fertilization due to the reduction in polyspermy. This can be attributed to the normal distribution of cortical granules in category 2 oocytes after maturation. -KEY WORDS: bovine, cortical granule, fertilization, morphology.J. Vet. Med. Sci. 61(5): 531-535, 1999 Sigma Chemical Co., St. Louis, U.S.A.), 0.2 mM sodium pyruvate (Sigma) and 50 µg/ml gentamicin sulfate (Sigma). During the washing procedure, oocytes were examined, selected and classified under a stereomicroscope by the following criteria. Category 1 represented oocytes with homogeneous ooplasm and multilayered cumulus investment. Category 2 represented oocytes having heterogeneous ooplasm with dark clusters, and multilayered cumulus investment.In vitro maturation, fertilization and culture: In vitro maturation, fertilization and culture were carried out using the procedure described previously [15]. Briefly, the COCs were washed once in the maturation medium; 25 mM Hepesbuffered TCM 199 supplemented with 10% fetal calf serum (Gibco Laboratories, Grand Island, NY, U.S.A.), 0.02 units/ ml follicle-stimulating hormone (Sigma), 1 µg/ml estradiol-17β (Sigma) and 0.2 mM sodium pyruvate and 50 µg/ml gentamicin sulfate. The oocytes in each category were cultured separately for 22 hr in a 50 µl droplet of maturation medium (10 or 11 oocytes per droplet) covered with paraffin oil at 39°C in a humidified atmosphere of 5% CO 2 in air. Frozen bovine semen collected from a Holstein bull was used for in vitro fertilization. After thawing the semen in a 37°C water bath for 30 sec, the motile sperm were separated using a discontinuous gradient with 45 and 90% Percoll (Pharmacia BioProcess, Uppsala, Sweden) by centrifugation at 700 × g for 20 min. The sperm were subsequently washed with a modified Brackett and Oliphant (mBO) medium [3] by centrifugation at 500 × g for 5 min. The mature oocytes were co-incubated with the sperm at the concentration of 5 × 10 6 sperm/ml in a 100 µl droplet of mBO medium containing 3 mg/ml fatty-acid-free BSA (Sigma) and 2.5 mM theophylline (Sigma) covered with paraffin oil for 20 hr at 39°C in a humidif...

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“…This may also be inferred from the marked reduction of the number of embryos and corpora lutea when anti-PMSG serum is administered before oestrus (Bouters et al, 1983). PMSG may therefore cause disorders during final follicular and oocyte maturation which is known to proceed according to a chronologically fixed hormonal sequence in normally cyclic cows (Dieleman et al, 1983a, b;Kruip et al, 1983;Dieleman & Blankenstein, 1984.…”

Section: Introductionmentioning

confidence: 99%

Effects of monoclonal antibody against PMSG administered shortly after the preovulatory LH surge on time and number of ovulations in PMSG/PG-treated cows

Dieleman¹,

Bevers²

1987

Reproduction

Self Cite

137

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Summary. Normally cyclic heifers received 2500 i.u. PMSG i.m. at Day 10 of the oestrous cycle and 15 mg prostaglandin (PG) i.m. 48 h later. From 30 h after PG the LH concentration in the peripheral blood was estimated every hour using a rapid RIA method which allowed the LH concentration to be known within 4 h. Monoclonal antibody against PMSG was injected in the jugular vein of 29 heifers at 4\m=.\8h after the maximum of the preovulatory LH peak; 28 heifers were not treated with anti-PMSG (controls). Peripheral blood concentrations of PMSG, LH, progesterone and oestradiol were compared. Ovaries were collected by ovariectomy at fixed times, 22\p=n-\30h after the LH peak, and numbers were counted of small (2\p=n-\10mm), large ( > 10 mm) and ovulated follicles, and of follicles with a stigma.In anti-PMSG-treated cows, the PMSG concentration fell sharply to non-detectable levels within 2 h of the treatment, indicating that PMSG was neutralized in these cows at the onset of final follicular maturation. In all cows, the concentration of oestradiol showed a significant decrease at about 8 h after the LH peak. After anti-PMSG treatment ovulations took place from 24 until 30 h after the LH peak, whereas in control cows follicles had already ovulated at or before 22 h and ovulations continued until 30 h. At 30 h 90% of the follicles had ovulated in anti-PMSG-treated cows vs 72% in the controls, resulting in 15 and 8 ovulations per cow respectively (P < 0\m=.\05).Also, administration of monoclonal antibody against PMSG synchronized final follicular maturation and shortened the period of multiple ovulations.In conclusion, neutralization of PMSG shortly after the preovulatory LH peak suppresses adverse effects of PMSG on final follicular maturation, leading to an almost 2-fold increase of the ovulation rate.

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Structural changes in bovine oocytes during final maturation in vivo

Cited by 236 publications

References 42 publications

Morphological and ultrastructural changes occurring during degeneration of goat preantral follicles preserved in vitro

Morphological and ultrastructural changes occurring during degeneration of goat preantral follicles preserved in vitro

In Vitro Fertilization and Cortical Granule Distribution of Bovine Oocytes Having Heterogeneous Ooplasm with Dark Clusters.

Effects of monoclonal antibody against PMSG administered shortly after the preovulatory LH surge on time and number of ovulations in PMSG/PG-treated cows

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