scholarly journals 121 HEAT SHOCK TO PIG OOCYTES DOES NOT INDUCE APOPTOSIS BUT REDUCES EMBRYO DEVELOPMENT

2005 ◽  
Vol 17 (2) ◽  
pp. 211
Author(s):  
J.-K. Tseng ◽  
P.-C. Tang ◽  
J.-C. Ju

Oocytes are susceptible to heat shock (HS) during the maturation process. It has been demonstrated that HS induces apoptosis and/or the expression of HS protein 70 (hsp 70) in in vitro-produced oocytes and embryos. The objectives of this study were to analyze the effects of HS on the development and apoptosis of pig oocytes and embryos. Porcine ovaries were collected from a local slaughterhouse and the cumulus-oocyte complexes (COCs) were aspirated from follicles 3–6 mm in diameter and subjected to standard in vitro maturation procedures at 39°C for 42 h. The in vitro matured oocytes were then randomly allocated to different HS treatments at 41.5°C for 0 (control, C0h), 1 (HS1h), 2 (HS2h), or 4 h (HS4h). An additional control group of oocytes was cultured for 4 h without HS (C4h). Data were analyzed by chi-square test. In Experiment 1, anti-hsp 70 (SPA-810AP, Stressgen, San Diego, CA, USA) and Western blotting were used to examine the expression of hsp 70. Results indicated that no significant difference of hsp 70 expression in metaphase II porcine oocytes occurred between controls and HS groups (P > 0.05, 7 replicates). In Experiment 2, apoptosis of metaphase II oocytes after HS was identified by annexin V-FITC (Sigma, St. Louis, MO, USA) staining and TUNEL (Roche, Indianapolis, IN, USA). No significant apoptotic signal was detected in the HS groups compared to the controls. The intensity of annexin V staining was not affected by HS, but it increased with the time of culture (P < 0.05, n = 24–37). In Experiment 3, the apoptotic rate and developmental competence of the HS-oocytes were evaluated by TUNEL assay (n = 123–137, 4 replicates). Parthenogenetic activation (n = 123–137) was performed by an electric pulse (2.2 kV cm−1) combined with 6-dimethyaminopurine treatment (6-DMAP, 2.5 μM, 4 h, Sigma). The cleavage rates in HS2h (43 ± 29%) and HS4h (35 ± 28%) decreased (P < 0.05) compared to those in C0h (62 ± 12%) and C4h (66 ± 8%). In addition, the blastocyst formation rates and total cell numbers reduced (P < 0.05) after 2 h (11 ± 10%, 20 ± 16) and 4 h (11 ± 8%, 19 ± 8) of HS treatments compared to those in C0h (23 ± 14%, 32 ± 22) and C4h (21 ± 11%, 27 ± 17), all respectively. The numbers of blastocysts with TUNEL-positive signals were not significantly different between the HS and control groups, but the signals increased (P < 0.05) before the 8-cell stage in HS groups (22–24%) compared to the C0h and C4h controls (16 and 11%), respectively. These results indicate that reduction in developmental competence of in vitro-matured pig oocytes after heat shock is not closely correlated to the expression of hsp 70 in the oocytes and to the apoptotic cell numbers in the blastocyst. Whether detection of apoptosis by TUNEL or annexin V-FITC in oocytes is a good indicator requires further investigation.

2011 ◽  
Vol 23 (7) ◽  
pp. 876 ◽  
Author(s):  
Dorit Kalo ◽  
Zvi Roth

Programmed cell death via the sphingomyelin pathway has been suggested to underlie heat-shock disturbance of oocyte developmental competence. A series of experiments were performed to characterise the role of the sphingolipid ceramide in heat-shock-induced apoptosis, and to determine whether ceramide formation can be regulated. Bovine cumulus–oocyte complexes (COCs) were aspirated from ovaries collected in the cold season (November–April), in vitro-matured, fertilised and cultured for 8 days. Exposure of COCs to heat shock (41°C) during maturation reduced cleavage rate and blastocyst formation relative to the control group (38.5°C). Annexin-V binding (V-FITC assay), which is associated with the early apoptotic event of membrane phosphatidylserine turnover, was higher in oocytes exposed to short-term versus long-term heat shock, suggesting that heat-shock-induced apoptosis involves membrane alterations. Similar to heat exposure, oocyte maturation with C2-ceramide had a dose-dependent deleterious effect on the first cleavages and subsequent embryonic development in association with increased annexin-V binding. Blocking endogenous ceramide generation with fumonisin B1, a specific inhibitor of dihydroceramide synthase (i.e. de novo formation), moderated, to some extent, the effects of heat shock on oocyte developmental competence, suggesting that ceramide plays an important role in heat-shock-induced apoptosis.


2018 ◽  
Vol 30 (1) ◽  
pp. 175
Author(s):  
G. A. Kim ◽  
J.-X. Jin ◽  
S. Lee ◽  
A. Taweechaipaisankul ◽  
B. C. Lee

Melatonin and its metabolites are powerful antioxidants and free radical scavengers. Because porcine embryos are vulnerable to oxidative stress in vitro, the addition of various protective chemicals to the culture medium, including melatonin, has been explored. The aim of this study was to investigate the effect of melatonin on in vitro developmental competence of porcine parthenogenetically activated (PA) embryos. Immature cumulus–oocyte complexes (COC) were collected and cultured in medium comprising TCM-199 supplemented with 10 ng mL−1 epidermal growth factor, 0.57 mM cysteine, 0.91 mM sodium pyruvate, 5 μL mL−1 insulin, transferrin selenium solution 100×, 10% porcine follicular fluid, 10 IU mL−1 eCG, and 10 IU mL−1 hCG for 44 h. Then, COC were denuded and PA with electrical stimulation, and PA embryos were cultured in porcine zygote medium 5 (PZM-5) supplemented with melatonin at increased concentrations (10−9, 10−7, 10−5 M) at 39°C in a humidified atmosphere of 5% O2, 5% CO2, and 90% N2 for 7 days. Subsequent embryo development, including cleavage rate, blastocyst rate, and blastocyst cell numbers, was compared between groups (mean no. of embryos; control, 27.14; 10−9 M, 28.86; 10−7 M, 27.71; 10−5 M, 26.43). The experiments were repeated 7 times for each treatment group. Statistical analyses of all data were performed using one-way ANOVA with Dunn’s multiple comparison test. Results are expressed as the mean ± SEM and all differences were considered significant at P < 0.05. No apparent effect on cleavage rate of melatonin treatment of various concentrations was noted. Blastocyst cell number did not show any significant difference between groups. However, the potential of PA oocytes to develop into blastocysts was significantly higher in the group supplemented with 10−9 M melatonin compared with the control group (35.44 ± 3.84 v. 24.71 ± 1.59) and other melatonin treated groups (10−5 M, 21.35 ± 2.82; 10−7 M, 24.01 ± 2.31; P < 0.05). These indicated that treatment with 10−9 M melatonin in embryo culture might reduce the oxidative stress properly compared with other concentrations, which results in improvement of blastocyst rate formation. In conclusion, treatment with 10−9 M melatonin positively promoted the blastocyst formation rate of porcine PA embryos with no beneficial effects on their blastocyst cell numbers or cleavage rate. This study was supported by the National Research Foundation (#2015R1C1A2A01054373; 2016M3A9B6903410), Research Institute for Veterinary Science and the BK21 PLUS Program.


2006 ◽  
Vol 18 (2) ◽  
pp. 159
Author(s):  
K. Loganathasamy ◽  
R. Rajhans ◽  
G. SaiKumar ◽  
G. T. Sharma

Cryopreservation of unfertilized oocytes at very low temperature (-196�C) is carried out to ensure their continuous availability during different assisted reproductive techniques. However, various problems associated with the freezing of oocytes influence their developmental competence, resulting in suboptimal embryo production. The present study was planned to assess the developmental competence of buffalo oocytes vitrified at different meiotic stages of maturation. Expression profile of developmentally important genes, viz, heat shock protein 70 (HSP 70) and glucose transporter 1 (Glut1), was verified in these vitrified warmed oocytes. Buffalo cumulus-oocyte complexes were collected from slaughterhouse ovaries and divided into six groups: control (no vitrification); 0 h group (vitrified before maturation), and 6-, 12-, 18-, and 24-h groups [vitrified respectively at 6, 12, 18, and 24 h post-in vitro maturation (IVM)]. Vitrification solution consisted of propylene glycol (40% w/v), and trehalose (0.25 mol/L) in PBS + BSA (4% w/v) and vitrification was carried out by directly plunging 0.25-mL French mini-straws into liquid nitrogen. After a minimum storage period of 7 days, the straws were thawed at 37�C for 30 sec. In all groups, the oocytes completed 24-h of maturation. After 24 h maturation, a few oocytes from each of the six groups were stained with ethidium bromide to reveal their nuclear status. The remaining oocytes were co-incubated with frozen thawed buffalo semen in fertilization TALP with 6 mg/mL fatty acid free BSA and 10 �g/mL heparin sodium salt for 18 h. Presumptive zygotes were cultured in mSOF for 8 days. Vitrified warmed oocytes were subjected to total RNA isolation and RT-PCR for detection of mRNA transcripts of HSP 70 and Glut1 genes. Data were analyzed by one-way ANOVA and F-test analysis. Differences of P < 0.05 were considered significant. The percentage of oocytes recovered from all five vitrification groups varied from 89 to 92 out of which 84-91% of oocytes were morphologically normal. A higher proportion of nonvitrified control oocytes (72.8%; 40/55) reached the metaphase II stage than for the oocytes vitrified at 24 (60%; 36/60), 18 (54.4%; 31/57), 12 (42.3%; 22/52), 6 (33.3%; 20/60), and 0 (31.7%; 19/60) h of IVM. The cleavage rate of nonvitrified control oocytes was higher (36.8%) than that of oocytes vitrified at 0 (1.6%), 6 (2.0%), 12 (3.2%), 18 (5.3%), and 24 (5.2%) h of IVM. With regard to subsequent development, 0- and 6-h oocytes were blocked at 8 cells, whereas in other groups development reached the late morula (4.8%) and blastocyst (3.5%) stages, confirming that the stage of maturation at which oocytes are vitrified influenced the nuclear maturation and developmental competence. Total RNA content was 2.24 � 0.40 ng/oocyte in the control group and 2.11 � 0.22 ng/oocyte in the group vitrified after 24 h of IVM. The expression pattern of HSP 70 and Glut1 was identical in control and vitrified groups, indicating that the vitrification protocol did not alter the expression pattern of these genes.


2007 ◽  
Vol 19 (1) ◽  
pp. 294
Author(s):  
J.-K. Tseng ◽  
P.-C. Tang ◽  
J.-C. Ju

Elevated ambient temperature has been known to be deleterious to the developmental competence of mammalian oocytes and embryos, although the mechanism is still unclear. The objective of this study was to determine the effect of heat shock (HS) on the alteration of intracellular calcium concentrations ([Ca2+]i) of matured pig oocytes by two different calcium releasing agents. Porcine cumulus–oocyte complexes were aspirated from the follicles (3–6 mm) and subjected to standard in vitro maturation procedure for 42 h. Matured oocytes were then randomly allocated to different heat treatments at 41.5°C for 0 (Control, C0h), 1 (HS1h), 2 (HS2h), or 4 h (HS4h). An additional control group was cultured for 4 h without heat shock (C4h). Oocytes were incubated with 2 µM fura-2 acetoxymethyl ester (AM) and 0.02% pluronic F-127 in Ca2+-free PBS (40 min) following heat shock, and then washed with Ca2+-free PBS (30 min) for detection of [Ca2+]i. Fluorescent images were captured with alternative excitation wavelengths at 340/380 nm by a rotating chopper disk equipped with an Axon imaging system. Data from both experiments were analyzed by ANOVA using the General Linear Model (GLM) of the SAS (SAS Institute, Inc., Cary, NC, USA). In Experiment 1, matured oocytes were activated by 200 mM thimerosal (10 min) following heat treatment. The maximal [Ca2+]i in the HS2h group was the highest among all treatment groups. The lowest maximal peak of [Ca2+]i was observed in the HS4h group, but it was still higher than that in the C4h group (P < 0.05). The total amount of Ca2+ release represented by the total area of the peaks in C4h was lower than in any other groups except HS4h (P < 0.05). In Experiment 2, each matured oocyte was injected with approximately 10 pL of inositol 1,4,5-triphosphate (IP3, 0.5 mM); the Ca2+ transient was recorded as described in the previous experiment. The maximal value of [Ca2+]i in the C4h group was still the lowest among the heat-shocked and C0h groups (P < 0.05). The total Ca2+ release in the HS2h group was the highest among all treatment groups, but only significantly higher than the HS1h and C4h groups (P < 0.05). A similar pattern of Ca2+ release in HS-oocytes was induced by thimerosal and IP3 stimulations. These results indicate that Ca2+ releasing capacity of matured pig oocytes is enhanced by a shorter duration of heat shock, but declines after prolonged exposure of heat shock and/or in vitro culture. The differential Ca2+ releasing capacity of heat-shocked oocytes prior to fertilization revealed physiological changes of pig oocytes after heat shock. This finding provides further insight for the low fertilization and developmental competence that occurs in farm species during hot seasons.


2016 ◽  
Vol 28 (2) ◽  
pp. 229
Author(s):  
S. M. B. Ulloa ◽  
J. Heinzmann ◽  
D. Herrmann ◽  
U. Baulain ◽  
K.-G. Hadeler ◽  
...  

High cyclic adenosine monophosphate (cAMP) concentrations are critical for maintaining oocyte meiotic arrest in vivo. For in vitro maturation (IVM), the oocyte is released mechanically from the follicle, which induces a significant drop in intra-oocyte cAMP levels, triggering non-physiological meiotic resumption. It has been proposed that modulation of cAMP before IVM can increase bovine blastocyst rates in vitro. Caffeine is a nonspecific competitive phosphodiesterases (PDE) inhibitor and can inhibit meiotic resumption of oocytes due to maintenance of cAMP levels. It has been reported that gamete treatment with caffeine can increase developmental potential. The current study evaluated the effects of pre-in vitro maturation culture with different concentrations of caffeine on meiotic progress, developmental rates and blastocyst cell numbers. Bovine ovaries were collected from a local abattoir. A total of 6648 cumulus-oocyte complexes were obtained by slicing. Caffeine was used in 5 different concentrations (1, 5, 10, 20, and 30 mM) during slicing, searching, and 2 h pre-IVM culture. A control group, with 2 h pre-IVM without caffeine (0 mM) and a standard control were also included. Oocytes were washed either after standard or pre-IVM treatments and cultured for 24 h in vitro without caffeine. After IVM, oocytes were fertilised in vitro for 19 h, and zygotes were cultured in vitro for 8 days until the blastocyst stage. Subsets of oocytes were fixed in 2% glutaraldehyde at 9, 20, and 24 h after IVM. Hoechst staining was performed to evaluate nuclear status of matured oocytes. Cleavage and blastocyst formation rates were evaluated at Days 3 and 8 after IVF. Expanded blastocysts from all treatments were submitted to differential staining. One-way ANOVA from R software was applied to evaluate differences in cleavage and blastocysts rates and blastocyst cell numbers. Fisher’s exact test complemented by Bonferroni correction was used to determine meiotic progress. Caffeine maintained oocytes in meiotic arrest after 9 h of IVM in a concentration-dependent manner (germinal vesicle: 79.0%, 92.2%, 66.7%, 55.1%, 56.9%, 43.9%, 30.2%, respectively, for 30, 20, 10, 5, 1, 0 mM and standard; P < 0.016). Cleavage rates were similar in all treatments; however 30 mM caffeine decreased blastocyst rates (Table 1; P < 0.05). The number of cells did not differ significantly among in vitro treatments (Table 1; P > 0.05). Developmental competence was not affected by 2 h pre-IVM culture. Caffeine supplementation before IVM delayed resumption of meiosis and affected embryo development. Table 1.In vitro developmental competence of oocytes treated with different caffeine concentrations before IVM


2009 ◽  
Vol 21 (1) ◽  
pp. 166
Author(s):  
Y. H. Zhang ◽  
H. T. Xi ◽  
Y. Liu ◽  
J. Li ◽  
A. Pederson ◽  
...  

The present study was designed to examine if frozen storage of porcine zygote medium (PZM3) plus 3 mg mL–1 BSA (Yoshioka et al. 2002 Bio. Reprod. 66, 112–119) is feasible to culture pig embryos produced by parthenogenetic activation and somatic nuclear transfer. Slaughterhouse-derived sow cumulus–oocyte complexes (COCs) were matured in TCM199 supplemented with 10% porcine follicle fluid, 5% cattle serum, 10 IU mL–1 eCG, 5 IU mL–1 hCG, 0.8 mm L-glutamine and 0.05 mg mL–1 gentamicin at 38.5°C, 100% humidity and 5% CO2 in air. For activation, cumulus cells were removed after 42 to 44 h of maturation, and the denuded oocytes with 1st polar body were activated with a double 160 V mm–1, 100 μs direct pulse followed by culture in PZM3. Each experiment was replicated at least three times. Data were expressed as mean ± SEM and analyzed by using chi-square module in SPSS 11.0, with P < 0.05 denoting significant difference. In Experiment 1, after preparation, liquid PZM3 was aliquoted to 50 mL falcon centrifuge tubes. Randomly, half of the tubes with PZM3 were put into –80°C freezers, and the rest were placed into 4°C refrigerator. Within one week after storage, a tube of frozen PZM3, while that stored at 4°C served as control, was warmed at 38.5°C in CO2 incubator, and more than three 4-well culture dishes were then made with 400 μL PZM3 in each well and balanced for at least 4 h in the incubator before experiment. The results showed that both cleavage (78/93, 83.9 ± 1.2% v. 87/103, 84.5 ± 1.8%, P > 0.05) and blastocyst (60/93, 65.2 ± 2.1% v. 65/103, 63.1 ± 3.8%, P > 0.05) rates were similar between frozen-warmed PZM3 and control, as was total cell numbers per blastocyst (50 ± 7 v. 47 ± 5, P > 0.05) between groups. In Experiment 2, we used somatic cloned embryos to investigate the effect of frozen-warmed PZM3 on pre-implantation development of such embryos. Our results indicated that no significant difference in rates of cleavage (68/95, 71.5 ± 5.1% v. 78/100, 78.1 ± 1.9%, P > 0.05), blastocyst formation (33/95, 34.6 ± 7.6% v. 78/100, 38.2 ± 3.5%, P > 0.05) and total cell numbers per blastocyst (40 ± 11 v. 48 ± 9, P > 0.05) was found between the test and control groups, designed the same as in Experiment 1. In Experiment 3, we tested whether PZM3 in frozen storage for 5 months was able to support in vitro development of parthenotes comparable to freshly-made ones. PZM3 after frozen storage for 5 months was warmed using the same method as Experiment 1, and the newly made PZM3 within 1 week of storage at 4°C acted as control. The results showed that although the cleavage (135/138, 97.8 ± 2.7% v. 117/129, 90.7 ± 3.1%, P > 0.05) and blastocyst (104/138, 75.4 ± 1.6% v. 84/129, 65.1 ± 2.3, P > 0.05) rates in control group were both slightly higher than that in the test group, no statistical differences was observed. We also found no significant difference in total cell numbers per blastocyst (48 ± 7 v. 46 ± 6, P > 0.05) between groups. Taken together, our results imply that frozen storage of PZM3 is feasible, and of practical value for culture pig embryos.


2014 ◽  
Vol 26 (1) ◽  
pp. 180 ◽  
Author(s):  
K. Syoji ◽  
K. Imai ◽  
H. Koyama ◽  
O. Dochi

The objective of this study was to investigate whether progesterone (P4) supplementation to in vitro maturation (IVM) medium could affect the competence of bovine oocyte to develop into blastocysts in vitro. Cumulus–oocyte complexes (COC) were collected by aspiration of ovarian follicles (2 to 6 mm in diameter) obtained from a local abattoir. The COC were matured for 20 h in TCM-199 supplemented with 5% calf serum and 0.02 AU mL–1 FSH at 38.5° in an atmosphere of 5% CO2 in air. After 18 h of gamete co-culture (5 × 106 sperms mL–1), presumptive zygotes were cultured in CRlaa containing 5% calf serum at 38.5°C in an atmosphere of 5% CO2, 5% O2, and 90% N2 for 9 days (fertilization = Day 0). Progesterone was added to the IVM medium 10 h after the start of the culture (1 μg group = 1 μg mL–1 of P4; 5 μg group = 5 μg mL–1 of P4; control group = no P4). The maturation (MII) rates were investigated after 20 h of starting the IVM culture. After maturation, the COC were denuded mechanically, and a part of the oocytes were mounted on slides, fixed with aceto-alcohol (1 : 3) solution for 48 h, stained with aceto-orcein, and observed under a phase-contrast microscope to determine their nuclear status (1 μg group: n = 32; 5 μg group: n = 28; control group: n = 31). The remaining COC were used for IVF. The cleavage rates were investigated on day 2, and the blastocyst formation rates were investigated on Days 7 to 9, respectively (1 μg group: n = 264; 5 μg group: n = 274; control group: n = 277). The blastocysts from Day 7 were used for differential staining of the inner cell mass (ICM) and trophectoderm cells (TE). The total cell numbers, ICM, and TE in the blastocysts were counted (1 μg group: n = 28; 5 μg group: n = 24; control group: n = 24). The rates of MII, cleavage, and blastocyst formation were expressed and analysed by the chi-squared test. Each set of cell numbers (mean ± standard error) was analysed by the unpaired t-test. The MII rate in the control group (76.7%) was significantly lower (P < 0.05) than that in the 1 μg group (93.8%). The cleavage rate in the 1 μg group (85.6%) was significantly higher (P < 0.05) than those in the control group (74.7%) and 5 μg group (77.4%). Further, the blastocyst formation rate in the 1 μg group (47.7%) and 5 μg group (43.4%) were significantly higher (P < 0.05) than that in the control group (35.0%). The ICM numbers (mean ± s.e.) were 39.5 ± 13.8 to 36.2 ± 8.9, the TE numbers were 74.4 ± 22.4 to 66.2 ± 12.9, the total cell numbers of blastocysts were 110.6 ± 28.2 to 103.0 ± 13.8. There was no significant difference in cell numbers among the groups. These results indicate that the cleavage and blastocyst formation rates can be improved by the addition of 1 μg mL–1 of P4 to the maturation medium.


Zygote ◽  
2007 ◽  
Vol 15 (2) ◽  
pp. 93-102 ◽  
Author(s):  
M. Kobayashi ◽  
S. Asakuma ◽  
Y. Fukui

SummaryThe present study was carried out to establish porcine defined IVP. In Experiments 1 and 2, we investigated the efficacy of additional 0.6 mM cystine and/or 100 µM cysteamine (Cys) to a defined TCM199 maturation medium with regard to the intracellular glutathione (GSH) concentration and the developmental competence of in vitro matured porcine oocytes following intracytoplasmic sperm injection (ICSI). The control medium was a modified TCM199 containing 0.05% (w/v) polyvinyl alcohol (PVA). Cys and/or cystine were added to the control medium. The control group and immature oocytes (presumptive germinal vesicle oocytes; GV) were prepared for GSH assay. In Experiment 3, the efficacy of epidermal growth factor (EGF) addition to a modified porcine zygote medium (mPZM) for in vitro culture (IVC) medium was investigated on embryonic development and the mean cell number of blastocysts following ICSI. As a positive or negative control, 0.3% BSA (mPZM-3) or 0.3% PVA (mPZM-4), respectively, was added to the base medium. The defined IVC medium was supplemented with 5 or 10 ng/ml EGF. In Experiment 1, no significant difference was found in the rates of cleavage (31.4–64.3%) and blastocyst formation (6.5–22.9%) among the treatment and control groups. The mean cell numbers per blastocyst ranged from 30 to 48 among the groups without significant differences. However, in Experiment 2, the intracellular GSH concentrations in the oocytes cultured in the medium supplemented with 100 µM Cys (9.6 pmol/oocyte) or Cys + cystine (9.9 pmol/oocyte) were significantly (p < 0.05) higher than the control (2.5 pmol/oocyte) and 0.6 mM cystine (6.5 pmol/oocyte) groups, but not different from the GV group (9.0 pmol/oocyte). The GSH concentration in the cystine group was also significantly (p < 0.05) higher than that in the control group, but not different from the GV group. In Experiment 3, the rates of cleavage and blastocyst formation and the mean cell numbers of blastocysts were not significantly different among the groups. However, the addition of 5 ng/ml EGF into the mPZM-4 resulted in a significantly (p < 0.05) higher blastocyst rate per cleaved embryo than the other two defined groups (mPZM-4 + 5 ng/ml: 48.6%, mPZM-4 and mPZM-4 +10 ng/ml: 23.4% and 23.1%, respectively).The present results indicate that the addition of Cys to a defined medium for in vitro maturation (IVM) of porcine oocytes increases intracellular GSH concentration. Further addition of cystine into the IVM medium containing 100 µM Cys is not necessary and TCM199 plus Cys (100 µM) could be used as a defined IVM medium for porcine oocytes. The addition of 5 ng/ml EGF to a defined IVC medium has enhanced subsequent development after ICSI. This study shows that porcine blastocysts can be produced by defined media throughout the steps of IVP (IVM, ICSI and IVC).


Reproduction ◽  
2013 ◽  
Vol 146 (4) ◽  
pp. 407-417 ◽  
Author(s):  
A Z Balboula ◽  
K Yamanaka ◽  
M Sakatani ◽  
M Kawahara ◽  
A O Hegab ◽  
...  

Cathepsin B was found to be correlated inversely with the quality of bovine oocytes and embryos. The aims of this study were to evaluate i) the relationship between heat shock during in vitro maturation (IVM) of bovine cumulus–oocyte complexes (COCs) and cathepsin B activity in relation to apoptosis and ii) the effect of supplementation of cathepsin B inhibitor (E-64) during IVM of heat-shocked COCs on embryonic development. After IVM at 38.5 °C for 22 h (control group) or at 38.5 °C for 5 h followed by 41 °C for 17 h (heat shock group) either with or without 1 μM E-64, activities and protein expression of cathepsin B and caspase 3 were evaluated as well as TUNEL staining. After IVF, developmental rate, total cell number, and the percentage of apoptotic cells in blastocysts were evaluated on day 8 (day 0, IVF day). Heat-shocked IVM COCs showed significantly high activities and expressions of both cathepsin B, and caspase 3 accompanied by a significant increase in number of TUNEL-positive cells. Addition of E-64 significantly decreased the activities of cathepsin B and caspase 3, and TUNEL-positive cells in heat-shocked IVM COCs. Moreover, addition of 1 μM E-64 during IVM under heat shock conditions significantly improved both developmental competence and quality of the produced embryos. These results indicate that heat shock induction of cathepsin B is associated with apoptosis of COCs, and inhibition of cathepsin B activity can improve the developmental competence of heat-shocked COCs during IVM.


2015 ◽  
Vol 27 (1) ◽  
pp. 235
Author(s):  
E. D. Souza ◽  
N. C. Rabelo ◽  
T. D. Araujo ◽  
C. M. Assunção ◽  
C. C. R. Quintão ◽  
...  

The heat shock protein 90kDa (HSP90) is a chaperone involved in protein homeostasis under normal and stress conditions. Its inhibition by 17-(allylamino)-17-demethoxygeldanamycin (17AAG, Sigma, St. Louis, MO, USA) for 12 or 24 h during in vitro maturation reduces the oocyte's ability to develop after in vitro fertilization (Souza et al. 2014 Reprod. Fert. Dev. 26, 197). This study aimed to evaluate the effect of treatment with 17AAG during the heat shock on oocyte developmental competence. Immature bovine COC were randomly allocated in 4 treatments during IVM: control = no heat shock or 17AAG; HS = heat shock (41.5°C) for the first 12 h of IVM; 17AAG = 2 µM 17AAG for the first 12 h of IVM; and 17AAG + HS = 2 µM 17AAG plus heat shock for the first 12 h of IVM. In vitro maturation was performed in Nunc plate containing 400 µL of TCM199 medium (Invitrogen, Carlsbad, CA, USA) supplemented with porcine FSH (Hertape Calier, Juatuba, Brazil) and 10% oestrus cow serum under 5% CO2 in air, 95% humidity, and 38.5°C for 24 h. Semen was processed by Percoll gradient (Nutricell, Campinas, Brazil) and oocytes were in vitro fertilized for 20 h with 2 × 106 spermatozoa mL–1 under the same IVM atmospheric conditions. Presumptive zygotes were completely denuded in a PBS solution with 0.1% hyaluronidase and then cultured in wells with 500 µL of modified CR2aa medium supplemented with 2.5% fetal calf serum (Nutricell) in an incubator at 38.5°C under 5% CO2, 5% O2, 90% N2, and saturated humidity. Cleavage rate was evaluated 72 h postfertilization and blastocyst rate was evaluated at Day 7 (D7) and 8 (D8). Data from 7 replicates were submitted to analysis of variance and means were compared by Student Newman Keul's test. There was no difference (P > 0.05) on cleavage rate among treatments. Heat shock or treatment with 17AAG, both for 12 h of IVM, decreased (P < 0.05) the blastocyst rate at D7 and D8 when compared to control but no significant difference between HS and 17AAG treatments was found (Table 1). However, the lowest (P < 0.05) blastocyst rate at D7 and D8 was achieved when oocytes were submitted simultaneously to 17AAG and heat shock for 12 h of IVM (17AAG + HS treatment, Table 1). In conclusion, the treatment with 17AAG during IVM worsens the deleterious effect of heat shock on oocyte developmental competence and suggests that HSP90 may also play role on cellular protection during heat shock in bovine oocytes. Table 1.Cleavage and blastocyst (Bl) rates at D7 and D8 for control, 17AAG, Heat Shock (HS), and 17AAG plus HS treatments Financial support comes from CNPq, FAPEMIG, and FAPES.


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