164 EFFECTS OF CUMULUS CELLS AND PITUITARY HORMONES ON AGE-ASSOCIATED CELLULAR CHANGES DURING THE PROLONGED CULTURE OF BOVINE OOCYTES

2014 ◽  
Vol 26 (1) ◽  
pp. 196
Author(s):  
I. Lebedeva ◽  
G. Singina ◽  
A. Lopukhov ◽  
N. Zinovieva
Keyword(s):  
Fetal Calf Serum ◽  
Calf Serum ◽  
Cumulus Cells ◽  
Pituitary Hormones ◽  
Meiotic Arrest ◽  
Parthenogenetic Activation ◽  
Cellular Changes ◽  
Prolonged Culture ◽  
Bovine Oocytes

In vivo and in vitro aging of mature mammalian oocytes heavily reduces their quality and developmental capacity. Therefore, the knowledge of physiological factors modulating the speed of oocyte aging is of great importance for successful reproduction. The goal of the present research was to study effects of cumulus cells (CC) and two related pituitary hormones, prolactin (PRL) and growth hormone (GH), on the dynamics of age-associated cellular changes during the prolonged culture of bovine oocytes in vitro. Bovine cumulus–oocyte complexes (COC) were cultured for 20 h in the following maturation medium: TCM 199 containing 10% fetal calf serum, 10 μg mL–1 porcine FSH, and 5 μg mL–1 ovine LH. After IVM, COC were transferred to the aging medium consisting of TCM-199 supplemented with 10% fetal calf serum and cultured for 0, 12, 24, or 36 h in the absence (Control) or presence of 50 ng mL–1 bovine PRL (Research Center for Endocrinology, Moscow, Russia) or 10 ng mL–1 recombinant bovine GH (Monsanto, St. Louis, MO, USA). A portion of in vitro-matured oocytes were denuded of their CC and cultured in the control aging medium. At the end of culture, the state of the nuclear material in oocytes and embryos was evaluated by Tarkowski's cytogenetic method. The number of oocytes undergoing spontaneous parthenogenetic activation in the respective groups was determined by summarising the numbers of embryos cleaved and oocytes reaching anaphase-II to telophase-II stages or containing a pronucleus. Destructive changes in CC were assessed using the morphological signs of apoptosis. The data from 3 to 5 replicates were analysed by ANOVA. In the control group of COC, a rise in the rate of metaphase-II (M-II) oocytes with abnormal chromosome configurations occurred by 12 h of aging [31.8 ± 4.6% (12 h) v. 17.5 ± 2.6% (0 h); P < 0.05] and persisted up to 36 h (70.4 ± 2.0%; P < 0.001). At the same time, the frequency of oocyte parthenogenetic activation markedly increased only between 0 and 36 h of aging (from 0% to 20.7 ± 3.4%; P < 0.001). The addition of PRL or GH to the aging medium or removal of CCs resulted in a decline in the rate of M-II oocytes with degenerative changes of chromosomes throughout the culture period (at least P < 0.05). Furthermore, PRL and GH reduced the frequency of the oocyte activation at 36 h of the prolonged culture (up to 5.4 ± 2.5 and 1.7 ± 1.7%, respectively; P < 0.01), although CC did not influence meiotic arrest at M-II. Meanwhile, the rate of degenerated CC steadily increased as the culture time increased from 0 h (10.3 ± 1.1%) to 36 h (22.7 ± 2.2%; P < 0.001) and was unaffected by both hormones. The data suggest that, in bovine COC, CC accelerate abnormal changes in the chromosomal structure of aging M-II oocytes, whereas PRL and GH may decelerate these changes and support meiotic arrest during the prolonged culture of in vitro-matured oocytes. This research was partially supported by RFBR (project no. 13-04-01888).

165 FETAL CALF SERUM INFLUENCES CYCLIC GMP PATHWAY, WHICH IN TURN AFFECTS THE LIPID CONTENT IN IN VITRO-MATURED BOVINE OOCYTES

2014 ◽  
Vol 26 (1) ◽  
pp. 196
Author(s):  
K. R. L. Schwarz ◽  
R. C. Botigelli ◽  
F. C. Castro ◽  
M. R. Chiaratti ◽  
C. L. V. Leal
Keyword(s):  
Lipid Content ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Cumulus Cells ◽  
Control Group ◽  
Maturation Medium ◽  
Cgmp Pathway ◽  
Bovine Oocytes ◽  
Synthesis And Degradation

The sensitivity of IVP embryos to cryopreservation is often associated with lipid accumulation in the cytoplasm induced by the presence of fetal calf serum (FCS) during culture. Intracellular levels of cyclic (c)AMP and cGMP are involved in the regulation of lipolysis in adipocytes; high levels stimulate lipolysis whereas low levels lead to lipogenesis. Both nucleotides are present in bovine oocytes, together with the enzymes for their synthesis and degradation. The aim of this study was to analysis the effect of FCS on the cGMP pathway and the influence of cGMP on cytoplasmic lipids in bovine oocytes. In experiments 1 and 2, cumulus–oocyte complexes (COC) were cultured for 24 h in maturation medium with different proportions of FCS (2 and 10%) and a control group was matured with 0.4% BSA. After this period, transcripts for cGMP pathway were assessed by real-time PCR (GUCY1B3 and PDE5, cGMP synthesis and degradation enzymes, respectively; experiment 1) in oocytes and cumulus cells, and cGMP levels were measured in COC using commercial enzyme immunoassay kits (EIA; experiment 2). In experiments 3 and 4, COC were matured for 24 h with 0.4% BSA and different concentrations of the phosphodiesterase (PDE)5 inhibitor (0, 10–7, and 10–5 M sildenafil) to inhibit cGMP degradation and a control group was matured with 0.4% BSA. The nucleotide levels were measured in COC (experiment 3) and the oocytes were stained with Nile Red (1 μg mL–1) for evaluation of lipid content (experiment 4). Statistical analyses were performed by ANOVA followed by Tukey post hoc test using SAS software (SAS Institute Inc., Cary, NC, USA). Data for gene expression from 5 replicates and for cGMP measurements and lipid content from 3 replicates were log10-transformed into before analyses. The level of significance was 5%. The presence of FCS reduced GUCY1B3 expression in both cells and increased PDE5A in cumulus cells (P < 0.05). In experiment 2, the groups treated with 2 (0.64 fmol/COC) and 10% FCS (1.04 fmol/COC) showed decreased cGMP levels compared with control (9.46 fmol/COC; P < 0.05). In experiment 3, inhibition of PDE5A increased cGMP levels in the treated groups (36 and 56 fmol/COC for 10–7 and 10–5 M sildenafil, respectively) compared with control (9.5 fmol/COC; P < 0.05). Therefore, sildenafil showed inverse effects compared with FCS (experiment 2). In experiment 4, oocytes treated with 10–7 and 10–5 M sildenafil showed a reduced lipid content compared with controls (11.6 ± 9.4 v. 13.9 μm2 fluorescence intensity, respectively; P < 0.05). The results suggest that FCS in maturation medium affects the cGMP pathway, interfering with the transcription of genes that control its levels, which in turn results in nucleotide reduction. Inhibition of PDE5 increases cGMP levels and reduces the lipid content of oocytes, indicating that changes in this pathway caused by FCS may affect lipid metabolism of oocytes. More studies are underway to better understand this mechanism. The authors acknowledge FAPESP 2012/00170-0 for financial support.

230 ROLE OF PITUITARY HORMONES AND CUMULUS CELLS IN MODULATING THE DEVELOPMENTAL CAPACITY OF AGING BOVINE OOCYTES

2015 ◽  
Vol 27 (1) ◽  
pp. 204
Author(s):  
G. Singina ◽  
I. Lebedeva ◽  
T. Taradajnic ◽  
N. Zinovieva
Keyword(s):  
Embryonic Development ◽  
Tyrosine Kinases ◽  
Cumulus Cells ◽  
Pituitary Hormones ◽  
Developmental Competence ◽  
Developmental Potential ◽  
Prolonged Culture ◽  
Bovine Oocytes

The competence for embryonic development acquired during the oocyte maturation attenuates during the subsequent oocyte aging both in vivo and in vitro. Thus, the successful control of the female fertility requires information regarding factors responsible for the oocyte protection from early aging. The aim of the present research was to study the pattern and pathways of actions of two closely related pituitary hormones, prolactin (PRL), and growth hormone (GH), on the developmental potential of bovine oocytes during their aging in vitro. Therefore, we analysed (1) effects of PRL and GH during the prolonged culture of bovine oocytes on their subsequent development up to the blastocyst stage and (2) the role of cumulus cells (CC) and tyrosine kinases, the well-known mediators of PRL and GH signalling, in these effects. Bovine cumulus-enclosed oocytes (CEO) were cultured for 22 h in the following maturation medium: TCM 199 containing 10% fetal calf serum (FCS), 10 μg mL–1 of porcine FSH, and 10 μg mL–1 of ovine LH. After IVM, CEO or denuded oocytes (DO) were transferred to the aging medium consisting of TCM 199 supplemented with 10% FCS and cultured for 10 h in the absence (Control) or presence of 50 ng mL–1 bovine PRL or 10 ng mL–1 recombinant bovine GH and/or 10 μg mL–1 genistein (a non-selective inhibitor of tyrosine kinases). Genistein was not applied in the case of aging DO, since their developmental potential was not affected by both hormones. Following the prolonged culture, oocytes underwent IVF and IVC. Embryos were cultured in CR1aa medium until Day 5 post-insemination and then transferred to the same medium supplemented with 5% FCS and cultured up to Day 8. The embryo development was evaluated at Days 2 and 8 for cleavage and blastocyst formation. The data from 5 to 6 replicates using 135–184 oocytes per treatment were analysed by ANOVA. Aging of oocytes in the control medium had no effect on the cleavage rate, but caused the blastocyst yield to decline (P < 0.001) from 31.1 ± 2.3% (CEO fertilized immediately after maturation) to 10.5 ± 2.4% (aged CEO) and 7.9 ± 1.9% (aged DO). Cleavage rates of aging CEO and DO were unaffected by both PRL and GH. In the case of CEO, the addition of PRL (but not GH) to the aging medium raised the blastocyst yield from 8.2 ± 0.9% to 15.2 ± 2.1% (P < 0.05), whereas the removal of CC abolished this effect, reducing the yield up to 9.1 ± 2.7% (P < 0.05). At the same time, genistein did not influence the blastocyst yield in the PRL-treated group. The findings demonstrate that PRL can inhibit the attenuation of the developmental competence of bovine oocytes aging in vitro, with this effect being achieved via cumulus cells. Tyrosine kinases are unlikely to mediate the beneficial action of PRL on the CEO capacity for embryonic development. Meanwhile, closely related GH does not affect the developmental competence of aging bovine oocytes.This research was supported by RFBR (project No. 13-04-01888).

201 ROLE OF THE NITRIC OXIDE SYSTEM IN EFFECTS OF PROLACTIN AND GROWTH HORMONE ON METAPHASE-II CHROMOSOMES IN BOVINE OOCYTES AGING IN VITRO

2016 ◽  
Vol 28 (2) ◽  
pp. 231
Author(s):  
I. Lebedeva ◽  
G. Singina ◽  
E. Shedova ◽  
A. Lopukhov ◽  
N. Zinovieva
Keyword(s):  
Nitric Oxide ◽  
Growth Hormone ◽  
Cumulus Cells ◽  
Total Activity ◽  
Inhibitory Effect ◽  
Pituitary Hormones ◽  
Oxide System ◽  
Nos Inhibitors ◽  
Bovine Oocytes

Aging of mammalian oocytes is the time-dependent process of cytological and molecular transformations leading to a decline in the ovum quality and developmental capacity. We have previously shown that 2 related pituitary hormones, prolactin (PRL) and growth hormone (GH), may decelerate abnormal changes in the morphology of metaphase II (MII) chromosomes in bovine cumulus-enclosed oocytes (CEO) aging in vitro. The goal of the present research was to examine the involvement of different isoforms of nitric oxide synthase (NOS) in the actions of PRL and GH on MII chromosomes in aging bovine oocytes. Bovine CEO were matured for 20 h in TCM 199 containing 10% FCS, 10 μg mL–1 porcine FSH, and 10 μg mL–1 ovine LH. After IVM, CEO or denuded oocytes (DO) were cultured for 24 h in the aging medium of TCM 199 supplemented with 10% FCS (control). In experimental groups, the medium contained either 50 ng mL–1 bovine PRL or 10 ng mL–1 bovine GH and/or NOS inhibitors. The following inhibitors were applied: (1) N-propyl-l-arginine (NPLA; an inhibitor of neuronal NOS (nNOS), 5 μM) and (2) L-NAME (an effective inhibitor of both endothelial NOS (eNOS) and nNOS, 20 μM). Destructive changes of MII chromosomes in oocytes were assessed by the following morphological signs: decondensation, partial adherence, chromosome clumping into a single mass, and fragmentation. The total activity of NOS in oocytes was determined by NADPH-diaphorase staining. The data from 4–5 replicates were analysed by ANOVA. During CEO aging in the control medium, the rate of MII oocytes with destructive changes of chromosomes rose from 16.8 ± 2.1% to 58.5 ± 1.4% (P < 0.001), whereas both PRL and GH reduced this rate up to 42.0 ± 1.3% and 46.5 ± 1.6%, respectively (P < 0.001). The nNOS inhibitor NPLA abolished (P < 0.001) the inhibitory effect of PRL on abnormal modifications of chromosomes in CEO but did not affect the frequency of these modifications in the control or GH-treated groups. In the absence of the hormones, L-NAME (the eNOS+nNOS inhibitor) decreased the rate of aging CEOs with chromosome abnormalities from 58.5 ± 1.4% to 41.2 ± 2.5% (P < 0.001), acting unidirectionally with PRL and GH. Meanwhile, L-NAME enhanced (P < 0.05) the suppressing effect of PRL on destructive changes of MII chromosomes but did not influence the similar effect of GH. At the same time the chromosome morphology in senescent DOs was unaffected by the hormones or NOS inhibitors. Furthermore, the total activity of NOS in oocytes separated of cumulus after 24 h of aging was similar in the control and experimental groups. Thus, the inhibitory effect of GH on abnormal modifications of MII chromosomes in aging bovine oocytes may be related to a reduction of the eNOS activity in cumulus cells, whereas the respective effect of PRL is likely to be achieved by both inactivation of eNOS and activation of nNOS. This research was supported by RFBR (No. 13–04–01888).

scholarly journals 99MACROMOLECULES FOR VITRIFYING BOVINE OOCYTES

2004 ◽  
Vol 16 (2) ◽  
pp. 171
Author(s):  
G. Horvath ◽  
G.E. Seidel
Keyword(s):  
Fetal Calf Serum ◽  
Calf Serum ◽  
Cumulus Cells ◽  
Defined Medium ◽  
Standard Procedures ◽  
Zona Hardening ◽  
Maturation Medium ◽  
Experimental Treatments ◽  
Bovine Oocytes

Vitrification of oocytes would make them available for research and clinical purposes wherever and whenever needed. However, development rates and quality of blastocysts arising from vitrified oocytes have been low. Zona hardening following exposure to vitrification solutions and cooling could contribute to low fertilization rates. Addition of fetal calf serum (FCS) to handling media and vitrification solutions can prevent zona hardening, but FCS may be detrimental to resulting embryos and spread viral diseases, and its composition varies among batches. Fetuin is the component responsible for the protective effect of FCS (Landim-Alvarenga FC et al., 2002 Anim. Reprod. Sci. 71, 181–191). Our objective was to determine whether fetuin is a suitable substitute for FCS during vitrification. Oocytes derived from slaughterhouse ovaries were matured in a chemically defined medium with hormones and with or without 1mgmL−1 fetuin at 39°C in 5% CO2 in air. At 22h after the start of maturation, oocytes were transferred to one of the following handling media: 2% BSA, 2% BSA+1mgmL−1 fetuin, or 20% FCS in TCM-199+HEPES (HTCM-199). In the same media plus 100IUmL−1 hyaluronidase, cumulus cells were partly removed by gentle pipetting. Oocytes with approximately 3 layers of cumulus were chosen for two-step vitrification. First, they were exposed to VS1 (10% ethylene glycol (EG), 10% DMSO, 6% PVP in HTCM-199) for 30s, then to VS2 (20% EG, 20% DMSO, 6% PVP, 0.48M galactose in HTCM-199) for 25s, loaded into cryoloops in groups of five, and plunged into liquid nitrogen. Rapidly warmed oocytes were moved stepwise in 0.5, 0.25, 0.125, and 0M galactose in HTCM-199+20% FCS, 3 min each. All procedures were conducted at 39°C. Warmed oocytes were placed in maturation medium for an additional hour, and then fertilized and cultured according to standard procedures (Olson SE and Seidel GE Jr 2000 J. Anim. Sci. 78, 152–157). About 2000 oocytes were used in 11 replicates with semen of 4 bulls. The experimental treatments and controls were: A: maturation BSA, handling BSA; B: maturation BSA, handling FCS; C: maturation BSA, handling BSA+fetuin; D: maturation BSA+fetuin, handling BSA+fetuin; E: non-vitrified control, maturation BSA; F: non-vitrified control, maturation BSA+fetuin (Table 1). Controls did not differ (P&gt;0.1) from each other, nor were there differences among vitrification treatments. Controls resulted in greater cleavage and more 8-cell embryos and blastocysts than vitrified treatments, and also tended to have higher cell numbers. In summary, fetuin can replace FCS during handling without decreasing the success of vitrification. Table 1 Development of vitrified oocytes and controls

Influence of day-0 and day-7 superovulated cow serum during development of bovine oocytes in vitro

1994 ◽  
Vol 6 (2) ◽  
pp. 261 ◽  
Author(s):  
A Boediono ◽  
M Takagi ◽  
S Saha ◽  
T Suzuki
Keyword(s):  
Culture Medium ◽  
Fetal Calf Serum ◽  
Culture Media ◽  
Calf Serum ◽  
Blastocyst Development ◽  
Cleavage Rate ◽  
Low Concentrations ◽  
Maturation Medium ◽  
Bovine Oocytes

Oocytes were matured in medium supplemented with 5% serum collected from superovulated cows at oestrus (Day-0 SCS) or at the time of embryo collection (Day-7 SCS), or in medium supplemented with fetal calf serum (FCS). After insemination using frozen-thawed sperm, oocytes were cultured in vitro with medium supplemented with 5% Day-0 SCS or 5% Day-7 SCS or 5% FCS. The proportions of embryos that cleaved were not significantly different among treatments, whereas development of the embryo to a blastocyst was significantly higher in the presence of SCS than FCS. When the four possible combinations of Day-0 SCS and Day-7 SCS were used in the maturation and culture media, there were no differences among treatments, except that the cleavage rate was significantly higher (P < 0.05) with Day-0 SCS in the maturation medium and Day-7 SCS in the culture medium than with Day-7 SCS in the maturation medium and Day-0 SCS in the culture medium. The proportions of embryos that cleaved and developed to blastocysts were not related with the level of progesterone and luteinizing hormone in the serum added to the maturation and culture media. However, the use of serum with low concentrations of glucose, fatty acids and cholesterol in the maturation medium and the culture medium tended to be associated with a higher rate of cleavage and blastocyst development.

161 Cumulus Cell Luteinization is Enhanced During Aging of Bovine Oocytes Matured In Vitro

2018 ◽  
Vol 30 (1) ◽  
pp. 220
Author(s):  
I. Y. Lebedeva ◽  
G. N. Singina ◽  
S. V. Uzbekova ◽  
P. Papillier ◽  
E. N. Shedova ◽  
...  
Keyword(s):  
Regulatory Protein ◽  
Calf Serum ◽  
Cumulus Cell ◽  
Transcript Level ◽  
Cumulus Cells ◽  
Control Group ◽  
Expression Of Genes ◽  
Bovine Oocytes

Maturing mammalian oocytes can prevent luteinization of cumulus cells (CC) both in vivo and in vitro by regulating CC steroidogenesis (Gilchrist et al. 2004 Anim. Reprod. Sci. 82-83, 431-446; Ramirez et al. 2016 Anim. Reprod. 14, 280). However, when the oocyte attains the metaphase II stage, aging processes are accelerated and may impair protective abilities of CC. The aim of the present research was to study the luteinization of CC surrounding aging bovine oocytes and its susceptibility to prolactin (PRL), which performs a luteotropic function in mammals. We analysed (1) the steroidogenic activity of CC during the prolonged culture of cumulus–oocyte complexes (COC), and (2) the expression of genes related to luteinization in CC. Bovine COC were matured in TCM-199 containing 10% fetal calf serum (FCS), 10 μg mL−1 porcine FSH, and 10 μg mL−1 ovine LH. After 22 h of IVM, COC were transferred to the aging medium consisting of TCM-199 supplemented with 10% FCS and cultured for 0, 12, or 24 h in the absence (Control) or presence of 50 ng mL−1 bovine PRL. Progesterone (P4) and oestradiol-17β (E2) levels in spent media were determined by ELISA. The expression of luteinization-related genes STAR (steroidogenic acute regulatory protein), HSD3B1 (3β-hydroxysteroid dehydrogenase type 1), PGR (genomic P4 receptor), and PGRMC1 and PGRMC2 (P4 receptor membrane components 1 and 2) was analysed by real-time RT-PCR. The data from 6 to 8 replicates (at least 170 oocytes for each condition) were analysed by ANOVA following by Tukey’s (steroidogenesis) or Dunn’s (gene expression) tests. In the control group, the level of P4 production exhibited by COC during 24-h aging was 5.5-fold higher than the level observed during in vitro maturation (1.50 ± 0.15 ng v. 0.27 ± 0.02 ng of P4/COC; P < 0.001). Conversely, E2 production by aging COC was 2.7 times lower than that by maturing COC (0.39 ± 0.05 pg v. 1.04 ± 0.05 pg of E2/COC; P < 0.001). The CC expression of genes responsible for P4 synthesis, STAR and HSD3B1, increased progressively by 24 h of aging (7.1- and 34.6-fold, respectively; P < 0.001). Meanwhile, the steroid secretion and expression of STAR and HSD3B1 genes were unaffected by PRL. The relative mRNA abundance of PGRMC1 increased 2.3-fold (P < 0.05) in the control (at 24 h) and PRL groups (at 12 h), while that of PGRMC2 did not change significantly in both groups. In addition, PGR transcript level decreased (P < 0.01) 9.9-fold at 12 h and 18.3-fold at 24 h aging of PRL-treated COC, whereas this decrease was only 5-fold (P < 0.05) at 24 h in Control. The findings indicate that aging of bovine oocytes matured in vitro enhances luteinization of surrounding CC. Prolactin does not affect steroidogenesis but may modulate the expression of P4 receptors in cumulus cells. This research was supported partly by FASO Russia and INRA (France).

Effects of fetal calf serum in culture medium on development of bovine oocytes matured and fertilized in vitro

1994 ◽  
Vol 41 (5) ◽  
pp. 1091-1098 ◽  
Author(s):  
J.M. Lim ◽  
O. Okitsu ◽  
K. Okuda ◽  
K. Niwa
Keyword(s):  
Culture Medium ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Bovine Oocytes
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