174 Follicular fluid extracellular vesicles obtained from Holstein cows kept under thermoneutral or heat stress conditions modify gene expression of in vitro-matured oocytes

2019 ◽  
Vol 31 (1) ◽  
pp. 211
Author(s):  
F. M. Dalanezi ◽  
R. A. Ferrazza ◽  
J. C. Ochoa ◽  
H. D. Mogllón ◽  
F. C. Destro ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heat Stress ◽  
Follicular Fluid ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Holstein Cows ◽  
Dna Integrity ◽  
Meiotic Progression ◽  
Expression Of Genes

Heat stress (HS) has a massive impact on bovine reproduction. In cows, some of these deleterious effects involve follicular development and oocyte quality. Extracellular vesicles (EV) secreted by granulosa cells play a critical role in the intrafollicular environment by directly influencing cumulus cells and oocyte functions. The objective of this study was to investigate the effect of follicular fluid EV obtained from Holstein cows kept under thermoneutral (TN) or HS conditions, on in vitro bovine oocyte maturation. Non-lactating Holstein cows were synchronized with the Ovsynch protocol and also received an intravaginal progesterone device. From ovulation day (Day 1), cows were randomly assigned to TN (26°C, 73% humidity; n=12) or HS (36°C, 70% humidity; n=12) environments. On Day 9, 2 follicles (F1 and F2) were individually aspirated and all remained follicles were ablated. Then, on Day 14, newly formed F1 and F2 were also aspirated. Follicular fluid from all follicles from each treatment was pooled and EV were obtained according to Silveira et al. (2017 PLoS One 12, 1-25) and diluted in PBS (100μL of PBS per mL of follicular fluid centrifuged). Pools of 20 cumulus-oocyte complexes (COC) grade 1 or 2 (Stojkovic et al. Biol Reprod 200164, 904-992], predominantly from Bos indicus, were submitted to the following treatment groups: Control (n=4): matured in 90μL of TCM-199 with Eagles’ salts, glutamine, NaHCO3, pyruvate, amikacin, and FSH (base medium); TN (n=4): matured in 81μL of base medium+9μL of TN EV suspension; and HS (n=4): matured in 81μL+9μL of HS EV suspension. All treatments were carried out at 38.5°C for 24h in a humid atmosphere with 5% CO2. After 24h of maturation, COC were evaluated for meiotic progression (Hoechst 33342 stain), DNA integrity (TUNEL stain), and expression of genes related to oocyte quality (TaqMan assay, Applied Biosystems/Thermo Fisher Scientific, Waltham, MA, USA). Results were analysed using ANOVA followed by Tukey post hoc test (P<0.05). When the experimental groups were compared with the control group, there was no treatment effect on meiotic progression, DNA integrity, or gene expression of cumulus cells. In the oocytes of the TN group, the genes HSF1, IGFBP2, BMP15, GDF9, CDCA8, HAS2, RPL15, STAT3,and PFKP were less expressed. We concluded that oocytes matured in the presence of EV from follicular fluid of cows kept under TN conditions had lesser expression of genes related to oocyte quality. This study was supported by FAPESP (Grant #2012/18297-7) and CAPES Foundation of Brazil.

183 GENE EXPRESSION OF IN VITRO-MATURATED OOCYTES CAN BE MODULATED BY FOLLICLE EXOSOMES FROM COWS KEPT UNDER THERMONEUTRAL OR HEAT STRESS CONDITIONS

2017 ◽  
Vol 29 (1) ◽  
pp. 200 ◽  
Author(s):  
F. M. Dalanezi ◽  
F. C. Destro ◽  
R. A. Ferrazza ◽  
H. D. Mogollon García ◽  
F. F. Franchi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heat Stress ◽  
Cell Viability ◽  
Oocyte Maturation ◽  
Follicular Fluid ◽  
Stress Conditions ◽  
Standard Medium ◽  
Humidity Index ◽  
Lower Expression

There are several intrafollicular agents that have the ability to interfere with the metabolism and development of the oocyte, among these we highlight the exosomes (EXO). Thus, the aim of this study was to evaluate the capacity of EXO extracted from the follicular fluid of cows kept under thermoneutral or heat stress conditions to modulate oocyte maturation in vitro. Twenty-four Holstein cows were subjected to the following treatments for 14 days: heat stress (HS; n = 12), 38°C, 60% RH, temperature-humidity index = 88; and thermo-neutral (TN; n = 12), 24°C, 60% RH, temperature-humidity index = 71. Cows had their follicles aspirated when their diameter reached 9 to 12 mm; all follicles with this diameter were aspirated. All follicular fluid aspirated from cows subjected to HS or TN was pooled forming the groups (HS and TN). The EXO were obtained by ultracentrifugation of follicular fluid (120,000 × g for 70 min at 4°C, twice) and had their presence confirmed by transmission electron microscopy. Bos indicus cumulus-oocyte complexes (COC) collected from ovaries obtained in commercial slaughterhouse, were pooled in groups of 20 COC and randomly subjected to 1 of the following treatments: Control, matured in standard medium (TCM 199, supplemented with Earle’s salts, glutamine, NaHCO3, pyruvate, FSH, and amikacin); HS-EXO, matured in standard medium added with 10 µL of a solution of follicular EXO from HS cows; and TN-EXO, matured in standard medium added with 10 µL of a solution of follicular EXO from TN cows. The procedures were repeated 4 times, always with 20 COC per treatment in each replica. After 22 h of maturation, COC were recovered and the expression of genes related to apoptosis protection (BCL2), cell viability (STAT3), cell maintenance (RPL15), oocyte competence (BMP15), oxidative stress (CPT1B), cumulus cell expansion (HAS2), cell cycle (CDCA8), and heat stress protection (HSF1) were assessed. Oocyte genes were differentially expressed according to the source of EXO. Groups were statistically analysed using ANOVA and Tukey tests. All genes, except CPT1B, showed lower expression in TN-EXO oocytes when compared with control and HS-EXO (P < 0.05). CPT1B showed a higher expression in HS-EXO oocytes (P < 0.05). The results showed that the addition of EXO from exogenous follicles can modulate the expression of oocytes genes related to cell viability and survival. The lower expression of these genes in TN-EXO suggested that the EXO obtained in TN conditions attenuate several genes related to the oocytes maturation and viability. Surprisingly, the control oocytes showed a similar gene expression pattern of the HS-EXO. In conclusion, EXO derived from follicular fluid of cows submitted to TN or HS conditions can modulate the gene expression of oocytes matured in vitro. These results open new perspectives for the use of theses EXO as a tool to increase the efficiency of in vitro oocyte maturation. Financial support from FAPESP #12/18297–7.

339. THE RELATIONSHIP BETWEEN DNA FRAGMENTATION IN MOUSE OOCYTES AND GENITAL TRACT MICROORGANISMS

2010 ◽  
Vol 22 (9) ◽  
pp. 139
Author(s):  
J. E. Harris ◽  
E. S. Pelzer ◽  
J. A. Allan ◽  
E. Whiteside ◽  
L. De Boer ◽  
...  
Keyword(s):  
Dna Fragmentation ◽  
Virulence Factors ◽  
Follicular Fluid ◽  
Genital Tract ◽  
Oocyte Quality ◽  
Dna Integrity ◽  
Sperm Dna Fragmentation ◽  
Mouse Oocytes ◽  
Tract Infections

Colonising bacteria detected within the follicular fluid of women undergoing assisted reproductive technology cycles has been associated with decreased embryo transfer rates and decreased pregnancy rates. The bacteria isolated from the follicular fluid of these women, at the time of trans-vaginal oocyte retrieval include Gram-positive anaerobic rods, Gram-negative anaerobic rods, streptococci, staphylococci, and lactobacilli. Some of these bacteria are opportunistic pathogens in the female genital tract. The expression of virulence factors including hyaluronidase and DNase, could affect the structural integrity of the oocyte and induce DNA fragmentation and apoptosis. Hyaluronin is a major carbohydrate component of the cumulus oocyte complex that could be a target for bacterial hyaluronidase. Other virulence factors associated with bacteria detected in cases of genital tract infections include the hydrolytic enzymes sialidase, β-galactosidase and β-N-acetylhexosaminidase (Howe 1999). Production of reactive oxygen species as a result of the presence of bacteria and bacterial heat shock proteins have been suggested as mechanisms responsible for increased DNA fragmentation and apoptotic progression of male gametes in colonised semen. Previous studies have not confirmed a direct relationship between sperm morphology and the level of sperm DNA fragmentation. DNA fragmentation in oocytes in relation to the presence of bacteria remains to be investigated. Oocyte quality is only determined by the assessment of cumulus cell morphology prior to in-vitro fertilisation. In-vitro testing of oocyte DNA integrity under various conditions may further the understanding of oocyte quality. In this study, mouse oocytes were used to investigate the structural and DNA integrity of oocytes after in vitro exposure to Lactobacillus spp., Streptococcus spp., and Staphylococcus spp. and determine whether the morphological appearance of the oocyte was predictive of the level of DNA fragmentation and whether DNA fragmentation can be attributed to certain bacterial species found colonising follicular fluid. (1) Howe L (1999). Mucinase and sialidase activity of the vaginal microflora: implications for the pathogenesis of preterm labour. International Journal of STD and AIDS 10(7), 442–446.

Effect of butafosfan supplementation during oocyte maturation on bovine embryo development

Zygote ◽  
2019 ◽  
Vol 27 (05) ◽  
pp. 321-328
Author(s):  
Lucas Teixeira Hax ◽  
Joao Alveiro Alvarado Rincón ◽  
Augusto Schneider ◽  
Lígia Margareth Cantarelli Pegoraro ◽  
Letícia Franco Collares ◽  
...  
Keyword(s):  
Gene Expression ◽  
Embryo Development ◽  
Oocyte Maturation ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Bovine Embryo ◽  
Cleavage Rate ◽  
Nuclear Maturation

SummaryAround 60–80% of oocytes maturated in vivo reached competence, while the proportion of maturation in vitro is rarely higher than 40%. In this sense, butafosfan has been used in vivo to improve metabolic condition of postpartum cows, and can represent an alternative to increase reproductive efficiency in cows. The aim of this study was to evaluate the addition of increasing doses of butafosfan during oocyte maturation in vitro on the initial embryo development in cattle. In total, 1400 cumulus–oocyte complexes (COCs) were distributed in four groups and maturated according to supplementation with increasing concentrations of butafosfan (0 mg/ml, 0.05 mg/ml, 0.1 mg/ml and 0.2 mg/ml). Then, 20 oocytes per group were collected to evaluate nuclear maturation and gene expression on cumulus cells and oocytes and the remaining oocytes were inseminated and cultured until day 7, when blastocysts were collected for gene expression analysis. A dose-dependent effect of butafosfan was observed, with decrease of cleavage rate and embryo development with higher doses. No difference between groups was observed in maturation rate and expression of genes related to oocyte quality. Our results suggest that butafosfan is prejudicial for oocytes, compromising cleavage and embryo development.

scholarly journals Extensive effects of in vitro oocyte maturation on rhesus monkey cumulus cell transcriptome

2011 ◽  
Vol 301 (1) ◽  
pp. E196-E209 ◽  
Author(s):  
Young S. Lee ◽  
Catherine A. VandeVoort ◽  
John P. Gaughan ◽  
Uros Midic ◽  
Zoran Obradovic ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rhesus Monkey ◽  
Oocyte Maturation ◽  
Gene Array ◽  
Cumulus Cell ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Cell Phenotype ◽  
Marker Genes

The elaboration of a quality oocyte is integrally linked to the correct developmental progression of cumulus cell phenotype. In humans and nonhuman primates, oocyte quality is diminished with in vitro maturation. To determine the changes in gene expression in rhesus monkey cumulus cells (CC) that occur during the final day prior to oocyte maturation and how these changes differ between in vitro (IVM) and in vivo maturation (VVM), we completed a detailed comparison of transcriptomes using the Affymetrix gene array. We observed a large number of genes differing in expression when comparing IVM-CC and VVM-CC directly but a much larger number of differences when comparing the transitions from the prematuration to the post-IVM and post-VVM states. We observed a truncation or delay in the normal pattern of gene regulation but also remarkable compensatory changes in gene expression during IVM. Among the genes affected by IVM are those that contribute to productive cell-cell interactions between cumulus cell and oocyte and between cumulus cells. Numerous genes involved in lipid metabolism are incorrectly regulated during IVM, and the synthesis of sex hormones appears not to be suppressed during IVM. We identified a panel of 24 marker genes, the expression of which should provide the foundation for understanding how IVM can be improved for monitoring IVM conditions and for diagnosing oocyte quality.

Oral propylene glycol modifies follicular fluid and gene expression profiles in cumulus–oocyte complexes and embryos in feed-restricted heifers

2018 ◽  
Vol 30 (3) ◽  
pp. 417 ◽  
Author(s):  
G. Gamarra ◽  
C. Ponsart ◽  
S. Lacaze ◽  
F. Nuttinck ◽  
A. Cordova ◽  
...  
Keyword(s):  
Gene Expression ◽  
Propylene Glycol ◽  
Follicular Fluid ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Cumulus Cells ◽  
Blastocyst Stage ◽  
Control Group ◽  
In Vitro Production

Dietary supplementation with propylene glycol (PG) increases in vitro production of high-quality embryos in feed-restricted heifers. The aim of the present study was to evaluate the effects of PG in feed-restricted heifers on follicular fluid insulin and insulin-like growth factor (IGF) 1 concentrations, expression of IGF system genes in oocytes and cumulus cells and the expression of selected genes in blastocysts. Feed-restricted (R) heifers were drenched with water or PG during induced oestrous cycles (400 mL of PG or water/drench, daily drenching at 1600 hours for the first 9 days of the oestrous cycle). Ovum pick-up (OPU) was performed after superovulation to produce in vitro embryos and without superovulation to recover oocytes, cumulus cells and follicular fluid. OPU was also performed in a control group (not feed restricted and no drenching). Follicular fluid IGF1 concentrations were reduced by R, and PG restored IGF1 concentrations to those seen in the control group. In cumulus cells, expression of IGF1, IGF1 receptor (IGF1R) and IGF binding protein 4 (IGFBP4) was decreased in the R group, and fully (IGF1 and IGF1R) or partially (IGFBP4) restored to control levels by PG. Blastocyst perilipin 2 (PLIN2; also known as adipophilin), Bcl-2-associated X protein (BAX), SCL2A1 (facilitated glucose/fructose transporter GLUT1), aquaporin 3 (AQP3), DNA (cytosine-5)-methyltransferase 3A (DNMT3A) and heat shock 70-kDa protein 9 (HSPA9B) expression were decreased in R heifers; PG restored the expression of the last four genes to control levels. In conclusion, these results suggest that, during follicular growth, PG exerts epigenetic regulatory effects on gene expression in blastocyst stage embryos.

scholarly journals 170 FOLLICULAR FLUID CONCENTRATION AND OOCYTE QUALITY FROM TOGGENBURG GOATS FED WITH UREA

2009 ◽  
Vol 21 (1) ◽  
pp. 184
Author(s):  
E. A. M. Amorim ◽  
L. S. Amorim ◽  
C. A. A. Torres ◽  
J. D. Guimãres ◽  
J. F. Fonseca ◽  
...  
Keyword(s):  
Follicular Fluid ◽  
Follicular Development ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Urea Concentration ◽  
Follicular Aspiration ◽  
Randomized Design ◽  
Fluid Concentration

Protein and urea concentrations impair oocyte and embryo development in vivo and in vitro through an unclear mechanism. A possible way to understand this process is to determine the concentration of hormones and metabolites in follicular fluid associated with normal development. The objective of this study was to determine the effect of dietary urea levels on follicular fluid concentration of hormones and metabolites and oocyte quality. A trial was conducted with 9 nonpregnant and nonlactating Saanen goats, which had been distributed in a randomized design and fed with diets with 0 (n = 4) and 2.4% of urea in the total dry matter (DM) of the diet (n = 5). Before follicle aspiration by laparotomy, the goats were synchronized by inserting intravaginal sponges containing 60 mg of acetate medroxyprogesterone (Progespon®, Sintex) for 10 days followed by 125 μg of cloprostenol (Ciosin® Coopers) 48 h before the removal of the sponge. The sponge was removed immediately before the follicular aspiration. The follicular development was stimulated with 70 mg of NIH-FSH-P1 (Folltropin V® Vetrepharm) i.m., and 300 IU of eCG i.m., (Novormon® Sintex) given 36 h before the follicular aspiration. Fluid from the 2 lartest follicles of each ovary were analyzed to determine the concentration of estradiol, progesterone, and testosterone by quimioluminesence, and glucose and urea concentrations were measured by enzymatic kit. The other follicles in each ovary were aspired with new needles and syringes and the oocyte quality was recorded. Oocytes were classified according to cytoplasma aspect and number of granulosa cells: Class A (dark cytoplasm and uniform aspect) with 3 (AMG) and <3 layers of cumulus cells (AmG); class B (cytoplasm with color alterations, desuniform aspect and vacuoles) with 3 (BMG) and <3 layers of cumulus cells (BmG); number of partially denuded oocytes (PD) and number of denuded oocytes (DO). Data were analyzed by ANOVA and treatment difference separated by SNK test. Follicular fluid estradiol concentration was lower in goats fed with urea (4.02 ± 0.16; 4.97 ± 0.18 ng mL–1; P < 0.05), progesterone concentration did not differ between treatments (2.48 ± 0.58; 3.37 ± 0.52 ng mL–1; P > 0.05), testosterone concentration was lower in the control animals (1.17 ± 0.48; 3.20 ± 0.43 ng mL–1; P < 0.05). The glucose (91.44 ± 3.60; 84.78 ± 5.58 mg dL–1) and urea concentration (23.04 ± 1.06; 18.00 ± 2.35) were greater in the animals treated with 2.4% compared with 0% of urea (P < 0.05), respectively. The number of oocytes in the different categories was not affected by treatment (P > 0.05): AMG 1.20 ± 1.09 v. 0.50 ± 0.57, AmG 4.20 ± 2.16 v. 3.50 ± 3.10, BMG 0.40 ± 0.54 v. 0.25 ± 0.50, BmG 1.40 ± 0.54 v. 1.75 ± 1.25, DO 10.20 ± 3.76 v. 11.50 ± 5.44, in the 0 and 2.4% of urea groups respectively. Only the number of PD (1.60 ± 0.54 v. 3.50 ± 1.91) recovered from animals treated with 2.4% was greater than in controls (P < 0.05). The hormone and metabolites concentration in follicular fluid as well as the oocyte quality was affected by the urea concentration of the diet. Supported by grant from: CNPq, FAPEMIG, Shering Plough®, Tecnopec®, Carbogel®.

182 EFFECTS OF IGF-1 OR IGF-1-LongR3 ON CELLULAR AND MOLECULAR ASPECTS OF CUMULUS-OOCYTE COMPLEXES DURING IN VITRO OOCYTE MATURATION IN CATTLE

2016 ◽  
Vol 28 (2) ◽  
pp. 222
Author(s):  
M. S. Araujo ◽  
M. D. Guastali ◽  
A. C. S. Castilho ◽  
F. Landim-Alvarenga
Keyword(s):  
Gene Expression ◽  
Oocyte Maturation ◽  
Cumulus Cell ◽  
Cumulus Cells ◽  
Synthetic Analogue ◽  
Nuclear Maturation ◽  
Meiotic Progression ◽  
Metaphase Stage ◽  
Bovine Oocytes

The insulin-like growth factor-1 recombinant -3 (IGF-1-LongR3), a synthetic analogue of IGF-1 with increased bioavailability has not yet been used in vitro maturation (IVM) medium of bovine oocytes. Therefore, the aim of this study was to evaluate and compare the addition effects of IGF-1-LongR3 or IGF-1 in IVM bovine oocytes on meiotic progression, apoptosis, and profile of oocytes genes (GDF9, BMP15, BAX, BCL2, OOSP1, IGFBP2, IGFBP4 and IGFBP5) and genes in cumulus cells (AREG, EGFR, FSHR, COX2, BAX, BCL2, IGFBP2, IGFBP4 and IGFBP5). Bovine ovaries were collected in slaughterhouses, and 739 oocytes with grades 1 or 2 were selected after aspiration of 2- to 8-mm follicles. IVM was carried out in TCM199 with FSH, LH, and antibiotics (BM) supplemented with 100 ng mL–1 IGF-1 or 100 ng mL–1 LongR3-IGF-1. Control oocytes were matured in BM supplemented with 0.1% polyvinyl alcohol (PVA) or 10% FCS. For all groups, maturation was performed during 22–24 h in an incubator at 38.5°C and 5% CO2 in air. Subsequently oocytes were denuded and analysed for apoptosis, nuclear maturation, and gene expression by TUNEL assay, staining Hoechst 33342, and RT-qPCR, respectively. Statistical analysis was performed using a linear mixed effects model, which correlated the change in metaphase stage 1 to 2 and the absence of apoptosis among the experimental groups. ANOVA and Tukey tests were used to analyse the results obtained by RT-qPCR. After 10 replicates of IVM, 339 oocytes were evaluated for meiotic progression and apoptosis and 400 oocytes for gene expression. There was no statistical difference between the experimental groups with respect to meiotic progression and apoptosis. BCL2 and IGFBP4 gene were less expressed in oocytes matured with IGF-1 and LongR3-IGF-1 compared with control groups. GFBP4 was also less expressed in cumulus cell of oocytes from the experimental groups. Moreover COX2 expression was statistically elevated in cumulus cells matured in the presence of IGF-1 and LongR3-IGF-1 It was possible to perform IVM of bovine oocytes in the presence of LongR3-IGF-1, allowing its use in replacement of IGF-1 and FCS. The results of this study will provide more information on the interaction of IGF with the IGFBP and its importance for oocyte maturation.

scholarly journals The Differential Metabolomes in Cumulus and Mural Granulosa Cells from Human Preovulatory Follicles

2021 ◽  
Author(s):  
Er-Meng Gao ◽  
Bongkoch Turathum ◽  
Ling Wang ◽  
Di Zhang ◽  
Yu-Bing Liu ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Granulosa Cells ◽  
Quantitative Polymerase Chain Reaction ◽  
Cumulus Cells ◽  
Cholesterol Transport ◽  
Vitro Fertilization ◽  
Expression Of Genes ◽  
Preovulatory Follicles ◽  
Morphological Differences

AbstractThis study evaluated the differences in metabolites between cumulus cells (CCs) and mural granulosa cells (MGCs) from human preovulatory follicles to understand the mechanism of oocyte maturation involving CCs and MGCs. CCs and MGCs were collected from women who were undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. The differences in morphology were determined by immunofluorescence. The metabolomics of CCs and MGCs was measured by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) followed by quantitative polymerase chain reaction (qPCR) and western blot analysis to further confirm the genes and proteins involved in oocyte maturation. CCs and MGCs were cultured for 48 h in vitro, and the medium was collected for detection of hormone levels. There were minor morphological differences between CCs and MGCs. LC-MS/MS analysis showed that there were differences in 101 metabolites between CCs and MGCs: 7 metabolites were upregulated in CCs, and 94 metabolites were upregulated in MGCs. The metabolites related to cholesterol transport and estradiol production were enriched in CCs, while metabolites related to antiapoptosis were enriched in MGCs. The expression of genes and proteins involved in cholesterol transport (ABCA1, LDLR, and SCARB1) and estradiol production (SULT2B1 and CYP19A1) was significantly higher in CCs, and the expression of genes and proteins involved in antiapoptosis (CRLS1, LPCAT3, and PLA2G4A) was significantly higher in MGCs. The level of estrogen in CCs was significantly higher than that in MGCs, while the progesterone level showed no significant differences. There are differences between the metabolomes of CCs and MGCs. These differences may be involved in the regulation of oocyte maturation.

scholarly journals Heat Shock Protein 70 Improves In Vitro Embryo Yield and Quality from Heat Stressed Bovine Oocytes

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1794
Author(s):  
Konstantina Stamperna ◽  
Themistoklis Giannoulis ◽  
Eleni Dovolou ◽  
Maria Kalemkeridou ◽  
Ioannis Nanas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 70 ◽  
Cumulus Cells ◽  
Intramolecular Interactions ◽  
Developmental Competence ◽  
Embryo Yield ◽  
Bovine Oocytes

Heat shock protein 70 (HSP70) is a chaperon that stabilizes unfolded or partially folded proteins, preventing inappropriate inter- and intramolecular interactions. Here, we examined the developmental competence of in vitro matured oocytes exposed to heat stress with or without HSP70. Bovine oocytes were matured for 24 h at 39 °C without (group C39) or with HSP70 (group H39) and at 41 °C for the first 6 h, followed by 16 h at 39 °C with (group H41) or without HSP70 (group C41). After insemination, zygotes were cultured for 9 days at 39 °C. Cleavage and embryo yield were assessed 48 h post insemination and on days 7, 8, 9, respectively. Gene expression was assessed by RT-PCR in oocytes, cumulus cells and blastocysts. In C41, blastocysts formation rate was lower than in C39 and on day 9 it was lower than in H41. In oocytes, HSP70 enhanced the expression of three HSP genes regardless of incubation temperature. HSP70 at 39 °C led to tight coordination of gene expression in oocytes and blastocysts, but not in cumulus cells. Our results imply that HSP70, by preventing apoptosis, supporting signal transduction, and increasing antioxidant protection of the embryo, protects heat stressed maturing bovine oocyte and restores its developmental competence.

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