Chlorpyrifos and endosulfan affect buffalo oocyte maturation, fertilization, and embryo development in vitro directly and through cumulus cells

2011 ◽  
Vol 26 (1) ◽  
pp. 57-67 ◽  
Author(s):  
S. Nandi ◽  
P.S.P. Gupta ◽  
S.C. Roy ◽  
S. Selvaraju ◽  
J.P. Ravindra
Reproduction ◽  
1994 ◽  
Vol 100 (1) ◽  
pp. 131-136 ◽  
Author(s):  
L. A. Johnston ◽  
J. J. Parrish ◽  
R. Monson ◽  
L. Leibfried-Rutledge ◽  
J. L. Susko-Parrish ◽  
...  

2004 ◽  
Vol 16 (2) ◽  
pp. 167
Author(s):  
P. Comizzoli ◽  
D.E. Wildt ◽  
B.S. Pukazhenthi

A thorough characterization of cryoprotectant (CPA) sensitivity is required to formulate a successful cryopreservation protocol for any biomaterial. The aim of this study was to characterize the toxic impact of various CPA types, concentrations, and exposure temperatures on the immature domestic cat oocyte. In Experiment 1, grade I immature oocytes (n=561) were exposed (30min; 25°C or 0°C) to 0M, 0.75M, 1.5M, or 3M of propylene glycol (PrOH) or ethylene glycol (EG) in PBS+20% fetal calf serum (v/v). After exposure, CPA was removed step-wise by subjecting oocytes to decreased CPA concentrations. Oocytes were cultured (30h; 38.5°C, 5% CO2) in IVM medium as reported previously (Wolfe and Wildt 1996 J. Reprod. Fertil. 106, 135–141). Oocytes were then fixed and stained to examine nuclear status (Hoechst 33342) and spindle integrity (FITC-labeled anti-α-tubulin antibodies; Sigma Chemical Co., St. Louis, MO). Experiment 2 was designed on the basis of Experiment 1 results to assess the impact of the spindle abnormalities on subsequent embryo development. Oocytes (n=776) were exposed to CPA conditions yielding optimal nuclear maturation with either high (0.75M or 3.0M PrOH or 1.5M EG at 25°C) or low (1.5M PrOH at 25°C) proportions of abnormal spindle. After IVM, oocytes were inseminated with thawed semen (5×105 motile sperm mL−1 ) in Ham’s F-10 (Irvine Scientific, St-Anna, CA). At 16h post-insemination, oocytes were fixed and stained (Hoechst 33342) to assess IVF success (pronuclear formation) or cultured in vitro for 7 days to assess embryo development. Data were analyzed by ANOVA and Tukey’s multiple comparison test. In Experiment 1, CPA treatment had no effect (NS) on meiotic progression to metaphase I. However, percentage of oocytes reaching metaphase II (MII) was reduced (P<0.05) in 3.0M PrOH at 0°C (29.3±8.3%; mean±SD), 3.0M EG at 25°C (33.7±8.9%), and 0°C (29.4±11.0%) compared to all other conditions examined (range, 52.0% to 62.0%). All CPA treatments also increased (P<0.05) spindle abnormalities at MII (range, 40.3% to 75.9%) compared to control (13.8±8.6%), except 1.5M PrOH at 25°C (20.7±10.1%). None of the CPA treatments in Experiment 2 influenced IVF success (range, 55% to 63%; NS). However, percentage of cleaved embryos was reduced (P<0.05) in 0.75M PrOH (32.1±4.1%), 1.5M EG (33.4±4.0%), and 3.0M PrOH (29.3±3.8%) compared to control (50.1±4.0%) or 1.5M PrOH (50.6±4.9%). Developmental competence (number of blastocysts relative to number of cleaved embryos) also was impaired (P<0.05) in 1.5M EG (16.5±7.4%) and 3.0M PrOH (14.9±7.8%) compared to the other conditions (range, 32.5% to 38.5%), including 1.5 PrOH at 25°C (32.5±7.8%). In conclusion, exposure of immature oocytes to 1.5M PrOH at 25°C does not adversely impact oocyte maturation, MII spindle, fertilization, or embryo development in vitro in the domestic cat.


2015 ◽  
Vol 27 (1) ◽  
pp. 203
Author(s):  
I. Lindgren ◽  
P. Humblot ◽  
D. Laskowski ◽  
Y. Sjunnesson

Dairy cow fertility has decreased during the last decades, and much evidence indicates that metabolic disorders are an important part of this decline. Insulin is a key factor in the metabolic challenge during the transition period that coincides with the oocyte maturation and may therefore have an impact on the early embryo development. The aim of this study was to test the effect of insulin during oocyte maturation on early embryo development by adding insulin during the oocyte maturation in vitro. In this study, abattoir-derived bovine ovaries were used and cumulus-oocyte complexes (n = 991) were in vitro matured for 22 h according to standard protocols. Insulin was added during maturation in vitro as follows: H (10 µg mL–1 of insulin), L (0.1 µg mL–1 of insulin), or Z (0 µg mL–1 of insulin). After maturation, oocytes were removed and fixed in paraformaldehyde before staining. Click-it TUNEL assay (Invitrogen, Stockholm, Sweden) was used for apoptotic staining and DRAQ5 (BioNordika, Stockholm, Sweden) for nuclear staining (n = 132). Cumulus-oocyte complexes were evaluated using laser scanning confocal microscope (Zeiss LSM 510, Zeiss, Oberkochen, Germany). Five levels of scans were used to assess oocyte maturation (MII stage) and apoptosis. Because of incomplete penetration of the TUNEL stain (3–5 layers of cumulus cells), only the outer 2 layers of the cumulus complex were investigated regarding apoptosis. Apoptotic index was calculated as apoptotic cells/total cells visualised. Remaining oocytes were fertilized and cultured in vitro until Day 8. Day 7 and Day 8 blastocyst formation was assessed as well as blastocyst stage and grade. Effect of insulin treatment on variables was analysed by ANOVA following arc sin √p transformation. Post-ANOVA comparisons between H+L group v. Z were performed by using the contrast option under GLM (Scheffé test). Results are presented as least squares means ± s.e. P-values ≤ 0.05 were considered as statistically significant. Insulin treatment during oocyte maturation in vitro had no significant effect on oocyte nuclear maturation or apoptotic index of the cumulus cells (Z: 0.052 ± 0.025, L: 0.039 ± 0.016, H: 0.077 ± 0.044, P > 0.05). No effect was seen on cleavage rates (Z: 0.85 ± 0.02, L: 0.85 ± 0.02, H: 0.89 ± 0.03, P > 0.05), but insulin treatment significantly decreased Day 7 rates from fertilized oocytes (Z: 0.19 ± 0.02, L: 0.14 ± 0.02, H: 0.12 ± 0.02, P < 0.05). This study also showed a significantly retarded developmental stage and decreased grade of blastocysts in insulin-treated groups taken together when compared with the control group (P < 0.05). In this study, no effect of insulin supplementation during in vitro maturation was seen on bovine oocyte maturation and apoptosis of cumulus cells, but blastocyst formation and development were negatively affected. Further studies are needed for understanding the relationship between the addition of insulin during maturation in vitro and impaired blastocyst formation. Insulin is a common supplement in the first phase of the first in vitro maturation medium for pig oocytes and is believed to have a beneficial effect on this species.Funding was received from Stiftelsen Nils Lagerlöfs Fond H12–0051-NLA.


2011 ◽  
Vol 23 (1) ◽  
pp. 236 ◽  
Author(s):  
K. Zhang ◽  
P. J. Hansen ◽  
A. D. Ealy

Oocyte competency is acquired during the course of folliculogenesis and is controlled by various endocrine and paracrine signals. One of these is fibroblast growth factor 2 (FGF2). Its expression is up-regulated in theca and granulosa cells during final maturation of a bovine follicle, and its cognate receptors are expressed in cumulus cells and oocytes throughout the final stages of oocyte maturation. The overall goal of this work was to describe how supplementing FGF2 during oocyte maturation in vitro affects oocyte maturation and subsequent embryo development. Cumulus–oocyte complexes (COC) were collected from bovine ovaries obtained from a local abattoir and cultured in defined TCM-based oocyte maturation medium. Depending on the study, oocytes were examined either during (6 h) or after (21 h) maturation or were fertilized in vitro and examined throughout in vitro embryo development in modified SOFF. Data were analysed with least-squares ANOVA using GLM of SAS. Adding 0.5 to 50 ng mL–1 of FGF2 did not affect cleavage rate or the percentage of 8 to 16 cell embryos at day 3 post-IVF. However, the blastocyst rate at day 7 was greater when oocytes were exposed to 0.5 ng mL–1 of FGF2 during maturation [30.0 ± 1.9% (17/109) v. 16.0 ± 2.6% (23/77) for nontreatment control; 4 replicates; P < 0.05], whereas higher doses of FGF2 did not affect blastocyst rates when compared with controls. Total cell number per blastocyst was not affected by FGF2 addition. The effects of FGF2 on oocyte maturation and cumulus expansion were examined to better understand how FGF2 improves oocyte competency. Adding 0.5 ng mL–1 of FGF2 did not affect the percentage of oocytes containing condensed chromatin after 6 h IVM or metaphase II (MII) rate after 21 h IVM, but 0.5 ng mL–1 of FGF2 treatment increased the cumulus expansion index score after 21 h IVM (P < 0.05). Interestingly, adding 5 ng mL–1 but not 50 ng mL–1 of FGF2 increased MII rate [61.5 ± 4.3% (53/120) for 5 ng mL–1 of FGF2 v. 46.9 ± 5.9% (64/104) for nontreatment controls; 7 replicates; P < 0.05], but neither FGF2 affected rates of chromatin condensation and cumulus expansion. Changes in the relative abundance for several putative oocyte competency markers and maternal genes (CTSB, Sprouty2, EGFR, FSHR, Has2, BMP15, GDF9, JY-1, Follistatin, H2A) were examined at 6 and 21 h after treatment with 0.5 ng mL–1 of FGF2 by quantitative RT-PCR. Relative amounts of 18S RNA was used as an internal control, and 2-ΔΔCT was used to quantify relative gene expression. The relative abundance of most of the transcripts examined was not affected by FGF2, but EGFR mRNA levels were greater after 6 h but not 21 h IVM in cumulus cells isolated from FGF2-supplemented COC (P = 0.057). In summary, improvements in blastocyst development were achieved by FGF2 treatment during oocyte maturation. The reason for the enhanced oocyte competency remains unclear, but it may occur in part because of improvements in cumulus expansion and production of EGFR. This project was supported by NRICGP number 2008-35203-19106 from the USDA-NIFA.


Author(s):  
A.A. Mohammed ◽  
T. Al-Shaheen ◽  
S. Al-Suwaiegh

Oocytes are bathed in extracellular fluid of the antral follicles, which is termed follicular fluid (FF). Follicular fluid is synthesized from secretions of theca, granulosa, and cumulus cells and from a transudate of blood plasma. Oocytes persist in meiotic arrest in antral follicles until luteinizing hormone (LH) surge or removal the oocytes from the ovarian follicles. This suggests that FF before LH surge might contain meiosis inhibiting factor(s). The microvasculatory bed of the follicular wall and the composition of FF undergo changes during follicular growth and development, which is important for oocyte maturation and subsequent embryo development. Therefore, it is expected that FF composition and components might change according to timing of FF aspiration from follicles. Hence, negative or positive effects could be expected when FF supplemented during oocyte maturation in vitro. Nutrition effects on microvasculatory bed of follicles and their sizes. Thus, the nutritional status of animals is a factor affected on oocyte maturation and embryo development. The present article reviews and discusses these effects.


2016 ◽  
Vol 51 (5) ◽  
pp. 827-830 ◽  
Author(s):  
JAA Rincón ◽  
EM Madeira ◽  
FT Campos ◽  
B Mion ◽  
JF Silva ◽  
...  

1992 ◽  
Vol 37 (1) ◽  
pp. 256 ◽  
Author(s):  
P. Mermillod ◽  
C. Boccart ◽  
C. Wils ◽  
A. Massip ◽  
F. Dessy

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