Role of roscovitine and IBMX on kinetics of nuclear and cytoplasmic maturation of bovine oocytes in vitro

The 3-isobutyl-1-methylxanthine (IBMX) is able to prevent resumption of meiosis by maintaining elevated cyclic AMP (cAMP) concentrations in the oocyte, and roscovitine, a purine known to specifically inhibit MPF kinase activity, maintains bovine oocytes at the germinal vesicle (GV) stage. The present study was conducted to analyze whether cytoplasmic maturation (examined by the pattern of cortical granule (CG) distribution) of bovine oocytes is improved during meiotic arrest with IBMX and roscovitine. Oocytes were matured in vitro in a 10% Knockout(SR) supplemented TCM-199 medium (Control) with either 0.5 mM IBMX or 25 mu M roscovitine (ROSC). Oocytes were stained with fluorescein isothiocyanate conjugated Lens culinaris agglutinin (FITC-LCA) for CG evaluation and with Hoechst 33342 for nuclear stage assessment. At 16 h of culture, the percentage of oocytes remaining in the GV stage was higher (P < 0.05) in the ROSC group (32.41%) compared with the Control and IBMX groups (8.61% and 9.73%, respectively). At 24h of culture, progression of meiosis to M II stage was retarded (P < 0.05) in the ROSC group (24.05%) compared to the Control (60.20%), whereas the IBMX group (33.88%) showed no significant difference to the other two groups. At 16h of maturation, the proportion of oocytes with CG in clusters (immature cytoplasm) was similar between the groups, as was the percentage of peripheral CG (mature) at 24h of maturation. The results of the present study demonstrated that the meiotic inhibitors IBMX and roscovitine delay the progression of nuclear maturation without affecting cytoplasmic maturation, assessed by the analysis of CG repositioning. (c) 2006 Elsevier B.V. All rights reserved.

Protein diets promote the maturation of oocytes and spawning of Piaractus mesopotamicus kept in cages

The objective of this study was to evaluate the effects of balanced diets on the maturation of oocytes and the reproductive performance of P. mesopotamicus in cages. A completely random design with 224 fish in 16 cages measuring 5 m(3) was employed for this purpose. The treatments consisted of diets containing 18, 24, 30, and 36% crude protein (CP) provided ad libitum. The external and internal morphological characteristics of the specimens were examined, as well as: the position of the germinal vesicle, the distribution of oocyte diameters, the fertilization and hatching rates, the number of oocytes released, the total number of oocytes, the remaining weight and total weight of the ovaries, the gonadosomatic index, the condition factor (K), and the histology of the oocytes and ovaries post-spawning and during ovarian regression. The diameters of the oocytes collected before the first hormonal application displayed a unimodal distribution for the lowest protein content and a polymodal distribution for the other treatments. A similar situation was seen during spawning. The lowest fertilization and hatching rates were found as a consequence of the treatment with 30% CP (P < 0.05). The greatest hatching rate occurred in the females fed 18% CP. The greatest total oocyte weight was found in the specimens that received between 30 and 36% CP. The lowest K index was found in the females fed 36% CP. In conclusion, a diet containing 18% CP satisfies the reproductive requirements of females adapted to this system.

Vitrification of immature feline oocytes with a commercial kit for bovine embryo vitrification

The aim of this study was to evaluate the suitability of a commercial kit for bovine embryo vitrification for cryopreserving cat oocytes and to evaluate comparatively the effects of its use with slow freezing procedure on cryotolerance in terms of morphology and oocyte resumption of meiosis. Germinal vesicle stage oocytes isolated from cat ovaries were either vitrified (n=72) using a vitrification kit for bovine embryo or slow frozen (n=69) by exposing oocyte to ethylene glycol solution before being transferred to a programmable embryo freezer. After thawing and warming, oocytes were cultured for 48h and then were examined for meiosis resumption using bisbenzimide fluorescent staining (Hoechst 33342). Fresh immature oocytes (n=92) were used as the control group. The proportion of oocytes recovered in a morphologically normal state after thawing/warming was significantly higher in frozen oocytes (94.5%) than in the vitrified ones (75%, p<0.01). Morphological integrity after culture was similar in vitrified (73.6%) and slow frozen oocytes (76.8%); however, only 37.5% of the morphologically normal oocytes resumed meiosis after vitrification compared to 60.9% of those submitted to slow freezing procedure (p<0.01). Fresh oocytes showed higher morphological integrity (91.3%) and meiosis resumption rates (82.6%, p<0.002) than cryopreserved oocytes, irrespective of the procedure used. These results suggest that immature cat oocytes vitrified with a kit for bovine embryos retain their capacity to resume meiosis after warming and culture, albeit at lower rates than slow frozen oocytes. Vitrification and slow freezing methods show similar proportions of oocytes with normal morphology after culture, which demonstrate that thawed and warmed oocytes that resist to cryodamage have the same chances to maintain their integrity after 48h of culture. © 2012 Blackwell Verlag GmbH.

O papel do fator de crescimento semelhante à insulina-l sobre os efeitos deletérios do choque térmico em oócitos bovinos no estádio de vesícula germinativa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Maturação nuclear de ovócitos de cadelas em estro e anestro submetidos à maturação in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da sazonalidade e da condição ovariana sobre a produção embrionária in vitro de gato doméstico (Felis catus, Linnaeus. 1758)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos de diferentes inibidores da meiose sobre a maturação in vitro de oócitos bovinos e subsequente tolerância dos embriões a vitrificação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Oogenesis in Laetacara araguaiae (Ottoni and Costa, 2009) (Labriformes: Cichlidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influencia das Fases de Anestro e Diestro sobre a Configuração da Cromatina em Vesícula Germinativa do Oócitos Caninos.

Fundação de Apoio à Pesquisa do Estado de São Paulo (FAPESP)

Efeito do fator de crescimento epidermal (EGF) na maturação in vitro de oócitos caninos

Fundação de Apoio à Pesquisa do Estado de São Paulo (FAPESP)

Heat stress induced alteration in bovine oocytes: functional and cellular aspects

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of Hormonal Supplementation on Nuclear Maturation and Cortical Granules Distribution of Canine Oocytes During Various Reproductive Stages

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles

Background: This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF) intensity and the nuclear (NM) and cytoplasmic (CM) in vitro maturation of human oocytes from stimulated cycles.Results: The ZP-BF was evaluated under an inverted microscope with a polarizing optical system and was scored as high/positive (when the ZP image presented a uniform and intense birefringence) or low/negative (when the image presented moderate and heterogeneous birefringence). CM was analyzed by evaluating the distribution of cortical granules (CGs) throughout the ooplasm by immunofluorescence staining. CM was classified as: complete, when CG was localized in the periphery; incomplete, when oocytes presented a cluster of CGs in the center; or in transition, when oocytes had both in clusters throughout cytoplasm and distributed in a layer in the cytoplasm periphery Nuclear maturation: From a total of 83 germinal vesicle (GV) stage oocytes, 58 of oocytes (69.9%) reached NM at the metaphase II stage. From these 58 oocytes matured in vitro, the high/positively scoring ZP-BF was presented in 82.7% of oocytes at the GV stage, in 75.8% of oocytes when at the metaphase I, and in 82.7% when oocytes reached MII. No relationship was observed between NM and ZP-BF positive/negative scores (P = 0.55). These variables had a low Pearson's correlation coefficient (r = 0.081). Cytoplasmic maturation: A total of 85 in vitro-matured MII oocytes were fixed for CM evaluation. Forty-nine oocytes of them (57.6%) showed the complete CM, 30 (61.2%) presented a high/positively scoring ZP-BF and 19 (38.8%) had a low/negatively scoring ZP-BF. From 36 oocytes (42.3%) with incomplete CM, 18 (50%) presented a high/positively scoring ZPBF and 18 (50%) had a low/negatively scoring ZP-BF. No relationship was observed between CM and ZP-BF positive/negative scores (P = 0.42). These variables had a low Pearson's correlation coefficient (r = 0.11).Conclusions: The current study demonstrated an absence of relationship between ZP-BF high/positive or low/negative score and nuclear and cytoplasmic in vitro maturation of oocytes from stimulation cycles.

The dynamics of RNA participation in the vitellogenesis of Rhipicephalus sanguineus ticks Latreille 1806 (Acari:Ixodidae). I. Nucleoli or Cajal bodies?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cytotoxic effects of permethrin in oocytes of Rhipicephalus sanguineus (Acari: Ixodidae) fully engorged females: I. Direct or indirect action of the acaricide in germ cells?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)