62 EXPOSURE TO ETHYLENE GLYCOL AND DIMETHYL SULFOXIDE CAUSES ACTIVATION AND SPINDLE ANOMALIES IN BUFFALO (BUBALUS BUBALIS) OOCYTES

2009 ◽  
Vol 21 (1) ◽  
pp. 131 ◽  
Author(s):  
M. De Blasi ◽  
E. Mariotti ◽  
M. Rubessa ◽  
S. Di Francesco ◽  
G. Campanile ◽  
...  

Despite the increasing interest, buffalo oocyte cryopreservation is still inefficient, especially in terms of blastocyst development after IVF. The aim of this work was to evaluate chromatin and spindle organization of buffalo in vitro-matured oocytes after vitrification/warming by cryotop and after their simple exposure to cryoprotectants (CP). An overall amount of 251 COC was selected and matured in vitro. In the vitrification group, COC were first exposed to 10% ethylene glycol (EG) + 10% DMSO for 3 min, and then to 20% EG + 20% of DMSO and 0.5 m sucrose, loaded on cryotops, and plunged into liquid nitrogen within 25 s. Oocytes were warmed into a 1.25 m sucrose solution for 1 min and then to decreasing concentrations of sucrose (0.625 m, 0.42 m, and 0.31 m) for 30s each. In order to test CP toxicity, COC were simply exposed to the vitrification and warming solutions. Two hours after warming, oocytes were fixed and immunostained for microtubules using a method previously described (Messinger SM and Albertini DF 1991 J. Cell Sci. 100, 289–298), stained for nuclei with Hoechst, and examined by fluorescence microscopy. Fresh in vitro-matured oocytes were fixed and stained as controls. Data were analyzed by chi-square test; results are shown in Table 1. The percentages of MII oocytes in the control and vitrification groups were greater than in the toxicity group, in which a greater percentage of telophase II stage oocytes were found compared with both the control and vitrification groups, indicating occurrence of activation. Of the MII oocytes, both exposure to CP and vitrification procedures gave greater percentages of oocytes with abnormal spindle and abnormal chromatin configuration compared with the control. An unexpected datum was the evidence of a significant percentage of spontaneously activated oocytes in the toxicity group. We speculate that the lack of activation in the vitrification group may be related to the slowing down of metabolic activity subsequent to thermal shock, and hence, that activation after vitrification may occur later than 2 h post-warming. In conclusion, the simple exposure to CP causes activation of the COC and damage to the cytoskeleton similar to that induced by the whole vitrification protocol. The damages to the meiotic spindle and DNA fragmentation may lead to aneuploidy incompatible with subsequent embryo development and account for the poor embryo development currently recorded in buffalo. Table 1.Chromatin and spindle organization in oocytes vitrified and exposed to cryoprotectants

2010 ◽  
Vol 22 (1) ◽  
pp. 184
Author(s):  
A. Gambini ◽  
J. Jarazo ◽  
R. Olivera ◽  
D. Salamone

The availability of viable equine oocytes is a limiting factor on in vitro embryo production; therefore, it is necessary to assess some of the variables that affect oocyte viability. The aim of our study was to evaluate one of those variables: the effect of time between the collection of the ovary and oocyte in vitro maturation. Ovaries of slaughtered mares were collected during the breeding season (Argentine, Southern hemisphere). They were separated in bags every half hour and treated separately after arriving at the laboratory. COCs were recovered by a combination of scraping and washing of all visible follicles with a syringe filled with DMEM supplemented with 1 mM sodium pyruvate and 15 IU mL-1 heparin. COCs were matured for 24 to 26 h in 3 groups, according to time interval: 4 to 7 (group I), 7 to 10 (II), and 10 to 12 (III) hours. The medium for maturation was TCM-199 supplemented with 10% fetal bovine serum (FBS), 1 μL mL-1 insulin-transferrin-selenium, 1 mM sodium pyruvate, 100 mM cysteamine, and 0.1 mg mL-1 of FSH at 39°C in a humidified atmosphere of 5% CO2 in air. The cumulus was removed by a trypsin treatment and vortexing in hyaluronidase (1 mg mL-1). Cloning and fusion procedures were performed following the zona-free technique described by Lagutina et al. (2007 Theriogenology 67, 90-98). Two experiments were carried out by using different activation protocols. In experiment 1, the activation process was 22 mM ionomycin in H-TALP for 4 min followed by 3h culture in 1.9 mM 6-DMAP in SOF, whereas in experiment 2, we used 8.7 mM ionomycin in H-TALP for 4 min followed by 4 h culture in 1 mM 6-DMAP and 10 mg mL-1 cycloheximide in SOF. Embryos were cultured in wells of well (WOW) system. Half of the medium was renewed on Day 3 with fresh SOF and on Day 5 with DMEM/F12 with 10% FBS. Cleavage was assessed 48 h after activation; the rate of blastocyst formation was recorded at Days 8 and 9. Results were compared using chi-square test (P < 0.05). In experiment 1, maturation rates were significantly different between group I (n = 135, 54.1%) and III (n = 94, 40.4%), group II did not differ from them (n = 138, 53%). Cleavage rates differed statistically between II (n = 44, 75%) and III (n = 27, 40.7%), but not with group I (n = 53, 98%). No significant differences were found in blastocyst development; however, we observed a certain tendency towards an increase in the blastocyst rate as the time interval was lower (I: 3/53, 5.7%; II: 1/44, 2.3%; III: 0/27, 0%). In experiment 2, there were no significant differences between group I and II in rates of maturation (n = 56, 59% v. n = 111, 44.5%), cleavage (n = 22, 91% v. n = 34, 82%) or blastocyst rates (1/22, 4.5% v. 7/34, 20.6%). We conclude that cloned equine embryo development, using the two activation protocols tested, is not affected when the time interval between ovary collection and oocyte IVM is within 4 to 10 h.


2010 ◽  
Vol 22 (1) ◽  
pp. 317
Author(s):  
I. Venditto ◽  
E. Mariotti ◽  
L. Boccia ◽  
M. Rubessa ◽  
M. De Blasi ◽  
...  

Fertilization is a critical step of the in vitro embryo production (IVEP) technology in buffalo. It is known that proteolytic enzymes are involved in different steps of the fertilization process; among these, a critical role may be played by the plasminogen activator-plasmin system. It has been demonstrated that plasmin, the active enzyme of this system, induces acrosome reaction (AR) in bull spermatozoa (Taitzoglou IA et al. 2003 Andrologia 35, 112-116). The aim of this study was to investigate the effect of plasmin on the ability of buffalo sperm to undergo the AR. Frozen- thawed sperm from 4 buffalo bulls were treated by swim-up and incubated with 0.01 mM heparin for 4 h. At 0, 2, and 4 h, aliquots of spermatozoa were exposed for 10 min to 60 μg mL-1 of lysophosphatidylcholine (LPC), as positive control, and to 0.01 μg mL-1 of plasmin. This concentration was chosen after a preliminary dose-response trial. Another sample from each treatment was incubated with IVF medium (negative control). After 10 min, sperm motility was evaluated and sperm were fixed in 37% formaldehyde and stained with trypan blue-Giemsa for subsequent microscopic examination. The total number of sperm counted, over 3 replicates, was 1269 for the negative control, 1293 for LPC, and 1238 for plasmin, equally distributed among incubation times. Differences among groups were analyzed by chi-square test. After swim-up, acrosomal loss was observed only in 4% of the sperm. The addition of 0.01 μg mL-1 of plasmin for 10 min to buffalo spermatozoa at time 0 significantly (P < 0.01) enhanced (23%) AR compared with the control (7.8%), with the same efficiency of LPC (17.1%). After 2 h of incubation with heparin, both plasmin and LPC increased the AR compared to the control (24.4, 20.1, and 14.0%, respectively; P < 0.01). After 4 h, plasmin gave higher percentages of AR (27.2%) compared to both the control (21.0%; P < 0.05) and LPC (19.2%; P < 0.01). Another interesting result is the improved motility recorded with plasmin compared to both the control and LPC groups at 2 h of incubation (90, 75, and 75%, respectively; P < 0.05) and at 4 h of incubation (75, 60, and 60%, respectively; P < 0.05). Finally, no differences in sperm viability were observed between plasmin and the control, whereas a decreased viability was found when LPC was used at 0 h (96.2, 95.0, and 89.0%, respectively, for plasmin, control, and LPC; P < 0.05), at 2 h (85.0, 87.5, and 77.0%, respectively, for plasmin, control, and LPC; P < 0.01), and at 4 h (85.0, 93.3, and 81.1%, respectively, for plasmin, control, and LPC; P < 0.01). In conclusion, we found that addition of plasmin to capacitated sperm increases the percentage of acrosome-reacted spermatozoa and improves motility. Our results suggest that plasmin may play a role in events surrounding fertilization and suggest to evaluate in further studies whether the addition of plasmin during IVF improves the IVEP efficiency in buffalo.


2016 ◽  
Vol 28 (2) ◽  
pp. 176
Author(s):  
N. A. S. Rocha-Frigoni ◽  
B. C. S. Leão ◽  
P. C. Dall'Acqua ◽  
M. Ambrogi ◽  
G. Z. Mingoti

The objective of this study was to evaluate the protective effect of insulin-like growth factor (IGF-1) on blastocyst development and cryotolerance of bovine embryos in in vitro culture (IVC) under oxidative stress induced by menadione (MD). Cumulus-oocyte complexes (n = 1421) were matured in TCM-199 with bicarbonate, hormones, and 10% FCS for 22 h. After fertilization, the presumptive zygotes were cultured up to 7 days in SOF medium with 2.5% FCS and 0.5% BSA (control), and also supplemented with 100 μM IGF-1 (IGF). At Day 6, MD was included in the culture medium (0 μM, control; or 5.0 μM, MD) during 24 h. Cultures were conducted at 38.5°C in 5% CO2 in air. The cleavage and blastocysts rates were evaluated, respectively, at Days 3 and 7 (IVF = Day 0). At Day 7, a sample of the blastocysts was stained with 5 μM H2DCFDA (Molecular Probes, Canada) to evaluate the intracellular ROS levels or was stained for TUNEL (In Situ Cell Death Detection Kit, Roche, Indianapolis, IN, USA). Stained embryos were immediately evaluated under an epifluorescence microscope (excitation 495/550 nm and emission 404/590 nm, respectively, for ROS and TUNEL), and the images of embryos stained with H2DCFDA were analysed by Q-Capture Pro image software for determining the fluorescent intensity. Other blastocysts were vitrified (Ingámed®, Maringá-PR, Brazil), and after warming, they were cultured for 24 h to evaluate the re-expansion rates. The results were compared by ANOVA followed by Student’s t-test (mean ± s.e.M) and re-expansion rates by chi-square test (P < 0.05). The cleavage rates did not differ (P > 0.05) among groups (77.1 ± 1.9% to 82.75 ± 2.2%). The blastocyst rates were similar between control (35.4 ± 2.0%) and IGF (34.5 ± 3.7%), and both were higher (P < 0.05) than MD (21.3 ± 2.7%); the IGF+MD group (28.3 ± 1.6%) was similar (P > 0.05) to all groups. The intracellular levels of ROS were higher (P < 0.05) for the MD group (21.7 ± 0.7) than for control (17.0 ± 1.6), and both were similar (P > 0.05) to the IGF (19.2 ± 0.6) and IGF+MD (18.0 ± 1.0) groups. The highest rates of apoptosis were found in the MD group (22.3% ± 2.3) and the smallest in IGF (9.1% ± 0.7), and both differed (P < 0.05) from control (12.8% ± 1.0), and IGF+MD (15.6% ± 1.6). The re-expansion rates were similar between control (77.4%) and IGF (69.2%), and both were higher (P < 0.05) than MD (49.1%); however, the IGF+MD group (57.6%) was similar (P > 0.05) to IGF and MD groups. In conclusion, the supplementation with IGF-1 during IVC reversed the detrimental effects of MD on embryonic levels of ROS and apoptosis, as well as improved the embryo development and cryotolerance of blastocysts under oxidative stress. Financial support was provided by FAPESP (#2012/10083–8 and #2013/07382–6).


2007 ◽  
Vol 19 (1) ◽  
pp. 281 ◽  
Author(s):  
I. Lagutina ◽  
G. Lazzari ◽  
C. Galli

Several factors affect nuclear transfer success. These include efficient parthenogenetic activation and embryo culture medium that should efficiently support pre-implantation development of good quality blastocysts. We investigated pig oocyte activation and embryo development in SOFaa in response to ionomycin (Io = 5 µM Io for 4 min; Io° = 15 µM Io for 20 min) and electric impulse (EL; one 30-µs pulse of DC 1.5 kV cm−1 in the presence of 50 µM Ca) in combination with 2 mM 6-DMAP or 10 µg mL−1 cycloheximide (CHX) +5 µg mL−1 cytochalasin B (CB) for 4 h. In addition, we studied the effect of elevated (1 mM) (Cheong et al. 2002 Mol. Reprod. Dev. 61, 488) in comparison with 50 µM Ca during EL activation on embryo development in SOFaa and NCSUaa-23. Porcine oocytes were recovered from slaughtered donors and matured in vitro for 44 h in DMEM-F12 supplemented with 10% FCS, 0.05 IU LH and FSH (Menogon®, Ferring, Milan, Italy), 0.3 mM cystine, 0.5 mM cysteamine, 50 ng mL−1 long-EGF, 100 ng mL−1 long-IGF1, 5 ng mL−1 bFGF (Sigma-Aldrich, Milan, Italy) in 5% CO2 at 38.5°C. The rates of cleavage, blastocyst formation (BL) and BL cell number on Day 7 (BL-D7) were recorded. All experiments were done with 3 replicates. The data were compared by chi-square test. There was no difference in the ability of Io (all groups) and EL + CB activated oocytes to cleave, whereas the additional treatment of EL-activated oocytes with DMAP and CHX + CB significantly increased cleavage. Io activation resulted in poor blastocyst development in comparison with all EL-activated groups (see Table 1). When calcium levels were elevated during EL activation, significantly more embryos developed in SOFaa (35.6%, n = 191 vs. 26%, n = 192; P &lt; 0.05), but no differences were observed with culture in NCSUaa-23 (about 56%). The BL rate was significantly higher in NCSUaa-23 vs. SOFaa (55.9%, n = 68 vs. 34.8%, n = 69, respectively); however, the BL total cell number was significantly higher in SOFaa (58 ± 18, n = 40 vs. 86 ± 35, n = 56, respectively; P &lt; 0.05). In conclusion, we have found that SOFaa and NCSUaa-23 differ in ability to support pig parthenogenetic embryo development. EL activation combined with elevated Ca significantly increased the embryo developmental capacity in SOFaa but not in NCSUaa-23. NCSUaa-23 was more efficient for embryo culture, whereas SOF produced BLs of higher quality. Table 1.Effect of activation protocol on the development of pig parthenogenetic embryos in SOFaa This work was supported by grants ISS-CS11 and Fondazione Cariplo.


2010 ◽  
Vol 22 (1) ◽  
pp. 299 ◽  
Author(s):  
E. Mariotti ◽  
S. Di Francesco ◽  
M. De Blasi ◽  
C. Siniscalchi ◽  
M. V. Suárez ◽  
...  

The overall in vitro embryo production efficiency in buffalo is hampered by the poor IVF efficiency. The aim of this work was to evaluate whether the fertilizing ability of buffalo sperm is improved by the presence of bovine oviductal cells (BOEC) during IVF. Because of limited availability of buffalo oocytes, this was assessed by heterologous IVF. Bovine oviducts were obtained at a local abattoir from cows that were in the preovulatory phase of a normal estrous cycle. BOEC recovered from 5 oviducts as previously described (Gualtieri and Talevi 2000 Biol. Reprod. 62, 1754-1762) were pooled and plated in 100 μL drops of TCM-199 + 10% FCS, 100 U mL-1 penicillin, 100 μg mL-1 streptomycin and 0.25 μg mL-1 amphotericin B under mineral oil. Medium was changed every 48 h up to Day 6, when cell confluence and cilia activity were optimal. On day of IVF the medium was removed from the drops and replaced with TALP supplemented with 0.2 mM penicillamine, 0.1 mM hypotaurine, and 0.01 mM heparin (IVF medium). Frozen-thawed sperm from an IVF-tested buffalo bull, treated by Percoll gradients, were used for all IVF groups (2 × 106 sperm mL-1). In vitro-matured bovine oocytes (n = 409), over 3 replicates, were distributed in 4 fertilization groups: (A) IVF medium alone (control); (B) BOEC monolayer + IVF medium; (C) sperm preincubated for 6 h in IVF medium; and (D) sperm preincubated for 6 h with BOEC + IVF medium. After 20 h of coincubation at 38.5°C and 5% CO2 in air, putative zygotes were denuded, washed, and cultured in SOF medium. Forty-eight hours after IVF, cleavage rate was evaluated, and cleaved and uncleaved oocytes were fixed in 60% methanol and stained with DAPI for nuclei examination under fluorescence microscope. Data were analyzed by chi-square test. Although cleavage rate was not different among groups (46.2, 55.8, 50.0, and 50.0% for A, B, C, and D, respectively), the monospermic penetration rate increased (P < 0.01) in group B (79.3%) compared with group A (69.6%), with intermediate values in groups C (75.2%) and D (76.0%). Interestingly, the percentage of advanced embryos (>4 cells) was higher (P < 0.01) in groups C and D (47.9 and 37.1%, respectively) than in group A (12.1%), whereas group B (21.0%) was only different from group C. We demonstrated that the fertilizing capacity of buffalo sperm, evaluated as oocyte penetration rate after heterologous IVF, is enhanced by the presence of BOEC. This suggests that IVF of buffalo oocytes on BOEC monolayer may improve the IVF efficiency in buffalo. The higher incidence of advanced embryos in both groups with preincubated sperm may be accounted for by an earlier accomplishment of capacitation, leading to anticipated oocyte penetration. However, because the penetration rate in these groups was not improved compared with the control, we hypothesize that sperm viability may have decreased and hence that shorter incubation times should be tested in further studies.


2007 ◽  
Vol 19 (1) ◽  
pp. 294
Author(s):  
R. C. S. Yadav ◽  
A. Sharma ◽  
G. N. Purohit

Morphological changes and in vitro nuclear maturation of buffalo cumulus–oocyte complexes (COCs) was evaluated subsequent to their cryopreservation by vitrification in solutions containing 4 M, 6 M, 8 M, and 10 M concentrations of glycerol (G) or ethylene glycol (EG) or their combination. COCs collected from buffalo ovaries by aspiration (n = 1342) were equilibrated in 50% of the vitrification solution and then placed in the vitrification solution (Dulbecco's phosphate-buffered saline+0.5M sucrose + 0.5% BSA + cryoprotectant). COCs were transferred to empty semen straws, kept over LN vapor for 2–3 min, and then plunged into LN. After 7–10 days of storage, COCs were warmed and evaluated for morphological damage. Morphologically normal COCs were cultured in vitro (9 replicates each with 5–10 oocytes in 50–100-µL culture drops) in TCM-199 medium supplemented with 5µgmL-1 FSH, 5µgmL-1 LH, and 1 ngmL-1 estradiol with 25mM HEPES, 0.25mM pyruvate, and antibiotics. The COCs were incubated for 24 h at 38±1°C and 5% CO2 in humidified air in a CO2 incubator and evaluated for nuclear maturation at the end of 24 h of culture. Freshly collected COCs were also matured in vitro and kept as controls (n=142). The proportions of COCs retrieved in morphologically normal form were compared by chi-square test; the arcsin transformed data of the proportions of oocytes matured was compared by Duncan's new multiple range test. The proportions of oocytes recovered in a morphologically normal form were highest in the 6M EG group (95.23%), followed by 8M EG (94.0%) and 6M G (90.6%) groups. At 10M concentration, a significantly (P <0.05) lower percentage of oocytes was morphologically normal. The morphological abnormalities recorded were change in shape, rupture of zona pellucida, and leakage of oocyte contents. A significantly higher (65.62%; P <0.05) proportion of fresh oocytes reached metaphase-II compared to oocytes vitrified in all concentrations of G and EG. The proportion of oocytes reaching metaphase-II increased with increasing concentrations of both G and EG, but at 10M concentration the proportion of oocytes reaching metaphase-II decreased. The proportions of COCs reaching metaphase-II in 4M, 6 M, 8M, and 10M glycerol were 6.9%, 21.2%, 25.7%, and 5.5%, respectively. The respective proportions of COCs reaching metaphase-II in 4M, 6 M, 8M, and 10M ethylene glycol were 21.9%, 34.3%, 40.8%, and 7.5%. No significant benefit of in vitro maturation of oocytes was seen for oocytes vitrified in a combination of both G and EG. It was concluded that although vitrification brings about some damage to the oocytes, yet it appears to be a good tool for oocyte cryopreservation, and 8M concentration of either G or EG appears to be optimum for vitrification of buffalo oocytes.


2009 ◽  
Vol 21 (1) ◽  
pp. 200
Author(s):  
S. Di Francesco ◽  
E. Mariotti ◽  
M. Rubessa ◽  
G. Campanile ◽  
R. Di Palo ◽  
...  

It was previously reported that osteopontin (OPN), an acidic single-chain phosphorylated glycoprotein found in the oviductal fluid in cattle (Gabler C et al. 2003 Reproduction 126, 721–729), is able to facilitate fertilization in this species (Gasparrini B et al. 2008 Reprod. Fertil. Dev. 20(Suppl. I), 180 abst). The present study aimed to investigate whether the addition of OPN to the fertilization medium would affect both cleavage and postfertilization embryo development in the buffalo. To assess the influence of OPN on cleavage and blastocyst rates, in vitro-matured oocytes were fertilized in modified Tyrode’s albumin lactate pyruvate medium (Lu KH et al. 1987 Vet. Rec. 121, 259–260) supplemented with penicillamine, hypotaurine, and heparin, in the presence of 0.0 (n = 258), 0.1 (n = 263), 1 (n = 261), and 10 μg mL–1 (n = 264) of OPN. In vitro fertilization was carried out with frozen–thawed spermatozoa from a bull already tested for IVF. After 20 to 22 h of co-incubation at 38.5°C and 5% CO2 in air, putative zygotes were gently pipetted to remove cumulus cells, washed, and transferred, 10 per droplet, into 20 μL of SOF medium including essential and nonessential amino acids and BSA (Tervit HR et al. 1972 J. Reprod. Fertil. 30(3), 493–497), in a controlled gas atmosphere consisting of 5% CO2, 7% O2, and 88% N2, in humidified air, at 38.5°C. The culture medium was changed on Day 5 (Day 0 = day of insemination), when cleavage rate was assessed and embryos were moved into fresh medium for an additional 2 days. On Day 7, development rates into blastocysts of superior quality were recorded. Differences in the percentages of both cleavage and blastocyst rates among groups were analyzed by chi-square test. Significantly higher cleavage rates (59.3, 70.3, 71.6, and 42.4%, respectively, in the control group and in the groups with 0.1, 1, and 10 μg mL–1 of OPN; P < 0.01) were observed in the groups with 0.1 and 1 μg mL–1 of OPN compared with the other groups. Likewise, higher blastocyst rate percentages (17.4, 27.4, 29.9, and 9.5%, respectively, in the control group and in the groups with 0.1, 1, and 10 μg mL–1 of OPN; P < 0.01) were observed in the groups with 0.1 and 1 μg mL–1 of OPN compared with the other groups. In conclusion, these results showed that addition of low concentrations of OPN in the fertilization medium improved both cleavage and postfertilization embryo development in the buffalo, whereas the higher concentration resulted in impaired late-stage embryo development.


2004 ◽  
Vol 16 (2) ◽  
pp. 261
Author(s):  
Y.S. Park ◽  
S.H. Choi ◽  
H.D. Park ◽  
M.D. Byun

In vitro embryo development is strongly influenced by IVM conditions. Increased duration of IVM may cause aging of the oocytes, which has a harmful effect on the embryo development. Oocyte maturation depends upon the synthesis of several proteins that may play important roles in the cytoplasmic maturation. These experiments were conducted to determine the effect of IVM duration(18-h or 24-h) and medium exchange (at 18h) on embryo development, and to investigate the protein quantities in IVM medium. Korean Native Cow (KNC) ovaries were obtained from a local slaughterhouse, and cumulus-oocyte complexes (COCs) were aspirated from 2- to 8-mm follicles. Groups of 15 COCs were matured in 50-μL drops of TCM-199 supplemented with 10% fetal calf serum (FBS), 1μgmL−1 MFSH, 10μgmLLH and 1μgmL−1 Estradiol-17β for 18h or 24h. In vitro-matured oocytes were fertilized using frozen-thawed percoll separated spermatozoa (Day 0) in fer-TALP medium for 20h and cultured in CR1aa medium supplemented with 0.3% BSA (before Day 3) or 10% FBS (After Day 3). All types of cultures were carried out in an incubator at 39°C, 5% CO2 in air. The total protein quantity in IVM medium at 18h or 24h were compared by 2-dimensional gel electrophoresis using a 10–15% polyacrylamide gradient gels. Data from three replicates were analyzed by chi-square test. The proportions of oocytes reaching the blastocyst stage was significantly higher in 18h IVM group than 24h IVM group (Table 1). However, there was no difference detected in blastocyst rate between 18h IVM group and 18h medium exchange group. Total protein quantity was reduced between 18h and 24h in IVM medium. There were 299 protein spots identified in IVM medium;; there was an increase at 10 spots in the IVM medium analyzed at 18h and a decrease of 20 spots at 24h. This study suggests that duration of IVM affects subsequent embryo development. The total protein quantity was decreased between 18h and 24h in IVM medium. These proteins may be absorbed into the oocytes and reduce development to the blastocyst stage. However, this may be overcome by IVM medium exchange. Table 1 Effects of duration of IVM and medium exchange on embryo development of KNC oocytes


2016 ◽  
Vol 46 (6) ◽  
pp. 1113-1118 ◽  
Author(s):  
Cláudio Francisco Brogni ◽  
Lain Uriel Ohlweiler ◽  
Norton Klein ◽  
Joana Claudia Mezzalira ◽  
Jose Cristani ◽  
...  

ABSTRACT: The main cause of low efficiency of in vitro produced porcine embryos is the high polyspermic penetration rates at fertilization, which is aggravated in low quality oocytes. Experiment 1 evaluated the embryo development in high and low quality oocytes. Experiment 2 evaluated the embryo development and quality of low quality oocytes fertilized with sperm pre-incubated during 0h (control), 0.5h, 1h and 1.5h. Experiment 3 investigated fertilization and monospermic rates of the same groups of Experiment 2. Experiment 4 evaluated embryo development, cell density, fertilization and monospermic rates of high quality oocytes using semen pre incubated during the best time observed in the previous experiments. Cleavage and blastocyst rates were analyzed by chi-square test, and remaining data by ANOVA and Tukey test (P≤0.05). The cleavage (74.8 vs 51.7%) and blastocyst (33.7 vs 9.8%) rates were greater in oocytes of high versus low quality, with no differences in cell density. Fertilization rates (65.6 to 79.5%) were not influenced by pre-incubation time. However, semen pre-incubation during 1.5h increased monospermic penetration (53.3%) and cleavage rates (92.5%) in low quality oocytes. Blastocyst rate was improved with 1.5h of semen pre incubation; however they were still lower than that observed with high quality control oocytes. Ultimately, pre-incubation did not influence fertilization, monospermic penetration, embryo development rates, nor cell density in oocytes of high quality. Low-quality porcine oocytes resulted in better rates of embryo development if in vitro fertilized with sperm pre-incubated for 1.5 hour.


2006 ◽  
Vol 18 (2) ◽  
pp. 161
Author(s):  
A. C. Nicacio ◽  
R. Simões ◽  
M. A. Peres ◽  
J. S. A. Gonçalves ◽  
M. E. O. D'Ávila Assumpção ◽  
...  

The aim of this study was to evaluate the viability of in vitro-produced bovine embryos after exposure to different cryoprotectant solutions and cryopreservation. Bovine ovaries were collected at slaughterhouse and oocytes were matured, fertilized, and cultured in vitro. The embryos were co-cultured on a granulosa cell monolayer in SOF + 5% FCS and nonessential amino acids. In Experiment 1, expanded blastocysts were exposed to 10% ethylene glycol (EG) solution for 10 min (Group EG) or to 10% EG solution for 10 min and to 20% EG + 20% glycerol (Gly) solution for 30 s (Group EG/Gly). Cryoprotectants were diluted with PBS + 0.2% BSA + 0.3 M sucrose and PBS + 0.2% BSA solutions, both for 3 min, and the hatching rate was evaluated after culture. In Experiment 2, after exposure, EG Group was cryopreserved by slow freezing procedure (1.2�C/min) and EG/Gly Group was vitrified on nitrogen vapor for 2 min. After thawing, cryoprotectants were diluted using PBS + 0.2% BSA + 0.3 M sucrose and PBS + 0.2% BSA solutions, both for 3 min; hatching rate was evaluated after culture. As a control group for both experiments, non exposed embryos were cultured and evaluated for hatching rate. In Experiment 1, the hatching rates were 59.72% (43/72) for control, 62.38% (63/101) for EG, and 69.00% (69/100) for EG/Gly groups. In Experiment 2, hatching rates were 59.72% (43/72) for control, 15.22% (7/46) for EG, and 0.00% (0/46) for EG/Gly groups. Results were analyzed by chi-square test. In Experiment 1, no differences were observed among groups (P > 0.05) and in Experiment 2, differences were observed among control, EG, and EG/Gly groups (P < 0.05). In conclusion, the cryoprotectants were not deleterious to the development of in vitro bovine embryos until hatching, but the cryopreservation procedures decreased embryo viability. This work was supported by FAPESP 04/05335-1.


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