scholarly journals Effect of beta-mercaptoethanol during in vitro fertilization procedures on sperm penetration into porcine oocytes and the early development in vitro

Reproduction ◽  
2005 ◽  
Vol 130 (6) ◽  
pp. 889-898 ◽  
Author(s):  
Hiroaki Funahashi

This study was carried out to determine the effects of beta-mercaptoethanol (bME) during a transient co-culture of gametes for 10 min, and/or the following culture until 6–9 h after insemination, on sperm penetration of porcine in vitro maturation (IVM) oocytes and the early development in vitro. When fresh spermatozoa were cultured in various concentrations of bME for 2 h, bME neutralized the stimulatory effect of caffeine-benzoate on sperm capacitation and the spontaneous acrosome reaction at 50–250 μmol/l. When 50 μmol/l bME were added during a transient co-culture of gametes for 10 min, the sperm penetration rate was reduced 9 h after insemination (70.5–82.0% vs 90.5–94.0% in the absence of bME), but the incidence of monospermic penetration was not affected. When 50 μmol/l bME were supplemented during culture after a transient co-culture, the sperm penetration rate was not affected, but the incidence of monospermy oocytes was increased (43.9–45.8% vs 31.7–34.3% in the absence of bME). The presence of bME following a transient co-culture minimized a decrease of oocyte glutathione content at 6 h after insemination (7.9 pmol/oocyte before in vitro fertilization (IVF), 6.7 pmol/oocyte in the presence of bME vs 5.5 pmol/oocyte in the absence of bME). When the distribution of cortical granules was evaluated 1 h after activation with calcium ionophore, mean pixel intensity of fluorescein isothiocyanate-labeled peanut agglutinin (FITC-PNA) at the cortex region was lower in the oocytes activated and cultured in the presence of 50 μmol/l bME. Although the presence of 50 μmol/l bME during a transient co-culture for 10 min and the following culture did not increased blastocyst formation (29.6–37.7%), 50 μmol/l bME during the following culture significantly increased the mean cell numbers per blastocyst (73.3–76.4 vs 51.2 in the presence and absence of bME respectively). These results demonstrate that supplementation with bME during IVF procedures, except during a transient co-culture period of gametes in the presence of caffeine, has a beneficial effect in maintaining the function of gametes, the incidence of normal fertilization and, consequently, the quality of IVF embryos.

Zygote ◽  
2010 ◽  
Vol 18 (4) ◽  
pp. 345-355 ◽  
Author(s):  
M.J. Palomo ◽  
T. Mogas ◽  
D. Izquierdo ◽  
M.T. Paramio

SummaryThe aims of the present study were: (1) to evaluate the influence of sperm concentration (ranging from 0.5 × 106 to 4 × 106 spermatozoa/ml) and length of the gamete co-incubation time (2, 4, 6, 8, 10, 12, 16, 20, 24 or 28 h) on in vitro fertilization (IVF), assessing the sperm penetration rate; (2) to investigate the kinetics of different semen parameters as motility, viability and acrosome status during the co-culture period; and (3) to analyse the effect of the presence of cumulus–oocytes complexes (COCs) on these parameters. To achieve these objectives, several experiments were carried out using in vitro matured oocytes from prepubertal goats. The main findings of this work are that: (1) in our conditions, the optimum sperm concentration is 4 × 106 sperm/ml, as this sperm:oocyte ratio (approximately 28,000) allowed us to obtain the highest penetration rate, without increasing polyspermy incidence; (2) the highest percentage of viable acrosome-reacted spermatozoa is observed between 8–12 h of gamete co-culture, while the penetration rate is maximum at 12 h of co-incubation; and (3) the presence of COCs seems to favour the acrosome reaction of free spermatozoa on IVF medium, but not significantly. In conclusion, we suggest that a gamete co-incubation for 12–14 h, with a concentration of 4 × 106 sperm/ml, would be sufficient to obtain the highest rate of penetration, reducing the exposure of oocytes to high levels of reactive oxygen species produced by spermatozoa, especially when a high sperm concentration is used to increase the caprine IVF outcome.


2007 ◽  
Vol 19 (1) ◽  
pp. 274
Author(s):  
I. Tokeshi ◽  
H. Tatemoto ◽  
N. Muto ◽  
T. Yoshimoto ◽  
S. Nakamura ◽  
...  

We previously reported that the anti-hyaluronidase agents oligosaccharide and tannic acid (TA) were efficient probes for promoting the normal fertilization process in terms of an effective decrease in the incidence of polyspermy, not only in cumulus-enclosed but also in denuded oocytes in pigs. It was unclear, however, why the polyspermic penetration into the zona pellucida (ZP) was directly prevented by the anti-hyaluronidase action. The present study was conducted to examine the effects of 3 tannin relatives [TA, gallic acid (GA), and ellagic acid (EA)] on IVF parameters and the acrosome reaction induced by the sperm–ZP interaction. The anti-hyaluronidase and radical-scavenging activities of tannin relatives were measured by the colorimetric and the DPPH methods, respectively. Porcine cumulus–oocyte complexes (COCs) were cultured for 44 h in 0.1 mL of TCM-199 supplemented with 0.6 mM cysteine, 40 mU mL-1 of FSH, 20 mU mL-1 of LH, and 10% porcine follicular fluid. After in vitro maturation (IVM), the COCs were freed from their cumulus cells and inseminated by frozen-thawed ejaculated sperm in modified Tris-buffered medium (IVF medium) containing 0 (control) or 5 �g mL-1 of tannin relatives. After 2 h of co-incubation, the oocytes were gently pipetted to remove loosely bound sperm and stained with Hoechst 33342 to count the number of ZP-bound sperm, or stained with fluorescein isothiocyanate (FITC)-PNA, PI, and 422,6-diamidino-2-phenylindole to evaluate the acrosomal status. At 10 h post-insemination, IVF parameters were examined by lacmoid staining. The data were analyzed by ANOVA and the Tukey-Kramer test. None of the tannin relatives caused a protective proteolytic modification of the ZP matrix or a reduction of the acrosomal proteolytic activity or the number of ZP-bound sperm. There was no difference in the sperm penetration rate even in the presence of tannin relatives (73-82%). However, the incidence of polyspermy was remarkably prevented by TA (32%; 31/98) and EA (21%; 20/94) compared with the control (58%; 58/100; P < 0.05), resulting from their strong anti-hyaluronidase actions, whereas GA without the anti-hyaluronidase action had no effect on the prevention of polyspermy (51%; 43/84). The rate of acrosome reaction induced by the sperm–ZP interaction was decreased by TA (15%; 123/833) and EA (16%; 110/708) compared with the control (25%; 238/939; P < 0.05), and a similar result was found in sperm binding to the pretreated ZP with 500 U of hyaluronidase for 2 h (18%; 351/1959). Interestingly, when sperm were incubated in IVF medium with 10 �g mL-1 of progesterone for 0.5 h to induce a compulsory acrosome reaction instead of the ZP, EA never disturbed the acrosome reaction (23%; 98/424) as control (23%; 102/437), although this reaction was blocked by TA (13%; 57/427) and GA (13%; 50/375), which possessed higher levels of radical-scavenging activity than EA (P < 0.05). These results indicate that the anti-hyaluronidase action of TA and EA effectively prevented polyspermy during porcine IVF as a consequence of suppression of the acrosome reaction functionally induced by the sperm–ZP interaction requiring the hyaluronidase intervention.


2018 ◽  
Vol 30 (1) ◽  
pp. 179
Author(s):  
D. M. Lombardo ◽  
M. S. Lorenzo ◽  
P. R. Cruzans ◽  
G. M. Teplitz ◽  
A. Maruri ◽  
...  

The aim of this study was to evaluate the effect of the antioxidant dimethylthiourea (DMTU) as a supplement during the collection and washing of cumulus–oocyte complexes (COC) on the apoptosis in cumulus cells (CC) and the competition for oocyte development in vitro. The COC were obtained by follicular aspiration. The aspiration and washing medium was TCM-199 with 10% porcine follicular fluid, 0.3 mM sodium pyruvate, and penicillin/streptomycin. Treated groups were supplemented with 2 or 20 mM DMTU. After 44 h of in vitro maturation (IVM), the percentage of nuclear maturation was determined by staining of the denuded oocytes with Hoechst 33442 (n = 357). After 18 h of in vitro fertilization (IVF) with 15°C refrigerated spermatozoa from boars of proven fertility, the suspected zygotes were stained with Hoechst 33342 to evaluate the percentages of sperm penetration (SP), monospermic penetration (MP), male pronucleus formation (MPN), and IVF efficiency (monospermic oocytes/total oocytes) (n = 260). In post-IVM CC, flow cytometry was performed after staining with annexin V-propidium iodide to evaluate apoptosis and viability (n = 90,000). Data were analysed with Flowing V 2.5.1 (http://flowingsoftware.btk.fi/). A comparison of proportion among categories was used (Fisher’s exact test), and significant differences were determined at P < 0.05. No effects were observed in the percentages of nuclear maturation. Treatments with DMTU significantly increased the SP (Control: 35%; 2 mM: 72.9%; 20 mM: 67.8%) without modifying the MP. Although in both treatments, the amount of MPN was always greater than in the control, the percentages of MPN formation did not show significant differences. The 20 mM treatment significantly increased the efficiency of IVF (control: 22.2%; 2 mM: 31.9%; 20 mM: 45.7%). In the CC of the treated groups, a significant increase in viability (control: 7.4%; 2 mM: 12.2%; 20 mM: 14.7%) and a decrease in early apoptosis (control: 60.4%; 2 mM: 55.5%; 20 mM: 57.1%) were observed. Late apoptosis decreased in the 20 mM treatment (27.3%) compared with the other experimental groups (control: 31.3%; 2 mM: 31.2%). The addition of DMTU during COC collection and washing reduce the ROS-mediated apoptosis in CC and optimize the efficiency of IVF. Besides, CC quality reflects the effect of DMTU on oocytes, so viability and apoptosis analysis on CC constitutes an interesting noninvasive method to assess oocyte competence.


Zygote ◽  
2008 ◽  
Vol 16 (3) ◽  
pp. 249-257 ◽  
Author(s):  
Seiji Kito ◽  
Yuki Ohta

SummaryTo optimize IVF conditions for BALB/c mice, which are known to have poor in vitro fertilizability, the requirements for sperm–ova interaction were studied by use of modified simplex optimization medium (mKSOM) as a basic medium. Modified human tubal fluid (mHTF) was used for sperm preincubation and acted as a positive control. When the two media were compared, neither capacitation nor fertilization was supported in mKSOM. Increasing the calcium concentration in mKSOM to 5 mM or more during sperm: ova coincubation improved zona penetration but not male pronuclear (MPN) formation to the same level as those cells incubated in mHTF. When medium osmolarity was varied from 230–305 mOsmol by NaCl at 5 mM CaCl2, MPN formation improved at 280 mOsmol or higher osmolarity to the same level as that found when using mHTF. When NaCl equivalent to 25–75 mOsmol was substituted with trehalose, no significant reduction in fertilization was observed. Substitution of NaCl equivalent to 75 mOsmol with other osmotic reagents (sucrose, choline chloride and sorbitol) resulted in similar levels of fertilization as found with mHTF, except for sorbitol, which reduced fertilization significantly caused by its detrimental effect on sperm viability. At isotonic osmolarity (305 mOsmol), maximum fertilization was observed at 5 mM CaCl2; lower or higher concentrations of CaCl2 resulted in reduced fertilization. Calcium and osmolarity, therefore, are important for sperm : ova interaction in BALB/c mice and the increases in calcium to 5 mM and osmolarity to 305 mOsmol are optimal for BALB/c sperm to penetrate through the zona and to form MPN.


2010 ◽  
Vol 88 (11) ◽  
pp. 1121-1128 ◽  
Author(s):  
K. Oliveira ◽  
W. E. Hable

Spawning for the American eel ( Anguilla rostrata (Le Sueur, 1817)) takes place in secretive locations within the Sargasso Sea, which has thus far prevented investigations of gametogenesis and early development in this ecologically and commercially important species. Attempts to induce maturation and reproduction in this species have been few and have produced limited results, with a single report of the production of gastrula-stage embryos. Here we report the successful maturation of female American eels. Maturation occurred within 13 weeks and ovulation was induced with a single injection of 17α,20β-dihydroxy-4-pregnen-3-one (DHP). Following in vitro fertilization, embryogenesis through hatching was observed and larvae were maintained for up to 6 days. We show that a crucial factor for successful fertilization is the stage of the oocyte at the time of induced ovulation. Oocytes that had not reached the migratory nucleus stage, or had passed this stage, were not successfully fertilized. These findings demonstrate that American eel can reproduce in the laboratory and previously untestable hypotheses pertaining to the developmental biology of this elusive species can now be explored.


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