356 BLASTOCYST DEVELOPMENT FROM DOMESTIC CAT OOCYTES INJECTED WITH DEHYDRATED SPERMATOZOA

2006 ◽  
Vol 18 (2) ◽  
pp. 285
Author(s):  
A. Moisan ◽  
S. Leibo ◽  
J. Lynn ◽  
M. Gómez ◽  
C. Pope ◽  
...  

Live offspring have been produced by intracytoplasmic sperm injection (ICSI) of dehydrated spermatozoa into mouse and rabbit oocytes (Wakayama and Yanagimachi 1998 Nature Biotechnol. 16, 639; Liu et al. 2004 Biol. Reprod. 70, 1776). The objective of the present study was to determine the capability of dehydrated domestic cat spermatozoa to fertilize oocytes after ICSI. Spermatozoa were collected from three toms by ejaculation into an artificial vagina. Freshly collected samples were layered under 1 mL of Tyrode's salt solution supplemented with HEPES, BSA, glutamine, pyruvate, lactate, and 50 mM ethyleneglyeotetraacetic acid (EGTA) pH = 8.2-8.4, and allowed to swim-up during a 12-min incubation at 38�C. From the upper 600 �L of the sperm suspension, four 100-�L aliquots were collected and placed into 2-mL glass ampoules, plunged into liquid nitrogen (LN2), freeze dried at -43�C to -45�C and 44 to 76 � 10-3 mbar pressure, and stored at 4�C. Four to twelve 10-�L aliquots of the same suspension were placed onto glass slides, air-dried for 30 min, and stored in a desiccator at room temperature. Domestic cat oocytes were collected from minced ovaries and allowed to mature in vitro for 22 to 24 h. After maturation, oocytes were either fertilized in vitro (IVF; n = 36), or sperm injected (ICSI) with fresh or refrigerated (n = 74), freeze-dried (n = 45), or air-dried (n = 45) spermatozoa. After ICSI or IVF, oocytes were cultured in a three-step-sequential medium (G�mez et al. 2004 Cloning Stem Cells 6, 247) for up to 8 days. Cleavage and development to the blastocyst stage was assessed on Days 2 and 8 of culture, respectively. Cleavage rates after IVF (56%), ICSI with freeze-dried (60%), or ICSI with fresh spermatozoa (59%) were higher than those obtained after ICSI with air-dried spermatozoa (35%; P < 0.05). Blastocyst development after ICSI treatments was obtained only with fresh spermatozoa (9%), and was lower than that obtained after IVF (25%; P < 0.05). Recently, one hatching blastocyst was produced when oocytes (n = 18) were exposed to calcium ionophore 2 h after ICSI with freeze-dried sperm. This is the first report that domestic cat embryos can be produced in vitro by injecting oocytes with dried spermatozoa.

2004 ◽  
Vol 16 (2) ◽  
pp. 202 ◽  
Author(s):  
W.F. Swanson ◽  
A.L. Manharth ◽  
J.B. Bond ◽  
H.L. Bateman ◽  
R.L. Krisher ◽  
...  

Domestic cat embryos typically are cultured in media formulated for somatic cells or embryos from rodents or livestock species. Under these conditions, blastocyst development has been inconsistent and delayed relative to embryos grown in vivo, and embryo viability following transfer has been low. Our goal is to systematically define the culture requirements of the feline embryo to improve embryo development and viability. The objective of this study was to determine the ionic (NaCl, KCl, KH2PO4, and CaCl2:MgSO4) preferences of domestic cat IVF embryos. Anestral female cats were injected (i.m.) with 150IU eCG followed 84h later by 100IUhCG. Oocytes were recovered via laparoscopic follicular aspiration approximately 24h post-hCG injection (Day 0). Semen was collected from one of two males by means of an artificial vagina and washed once in HEPES-buffered IVF medium. Mature cumulus-oocyte complexes were co-incubated with 2.5–5×105 motile sperm mL−1 in IVF medium (100mM NaCl, 4.0mM KCl, 1.0mM KH2 PO4, 2.0mM CaCl2, 1.0mM MgSO4-7H2O, 25.0mM NaHCO3, 3.0mM glucose, 0.1mM pyruvate, 6.0mM L-lactate, 1.0mM glutamine, 0.1mM taurine, 1×MEM nonessential amino acids, 50μgmL−1 gentamicin, and 4.0mgmL−1 BSA) for 19 to 22h in 6% CO2 in air (38.7°C). Cumulus cells were removed and embryos cultured (8–11 embryos/50μL drop; 6% CO2, 5% O2, 89% N2, 38.7°C) in media containing 100.0 or 120.0mM NaCl, 4.0 or 8.0mM KCl, 0.25 or 1.0mM KH2PO4, and 1.0mM:2.0mM or 2.0mM:1.0mM CaCl2:MgSO4 (2×2×2×2 factorial design). The remaining components of the culture medium were identical to the IVF medium (but w/o gentamicin). Development to the blastocyst stage by Day 6, metabolism (glycolysis and pyruvate) of each blastocyst, and final cell number (Hoechst 33342 staining) of all embryos were evaluated. Final cell number of cleaved embryos and development to the blastocyst stage were analyzed using analysis of variance in the GLIMMIX macro of SAS. A total of 236 oocytes were inseminated, yielding 128 cleaved embryos (54%), including 6 blastocysts (4.7% of cleaved embryos). Cell number was not (P&gt;0.05) affected by NaCl, KCl, or KH2PO4 concentrations, but tended (P=0.057) to be higher after culture in 2.0mM:1.0mM CaCl2:MgSO4. Treatments did not significantly affect (P&gt;0.05) development to the blastocyst stage, but numerically more blastocysts were produced in 100.0mM NaCl (4/6), 8.0mM KCl (5/6), or 1.0mM KH2PO4 (5/6). Both CaCl2:MgSO4 ratios resulted in 3 blastocysts. Blastocysts contained 61.08±5.1 (mean±SEM, n=6) cells and actively metabolized glucose (glycolysis, 3.7±0.8pmol/embryo/3h or 0.06±0.01pmol/cell/3h) and pyruvate (0.75±0.27pmol/embryo/3h or 0.013±0.005pmol/cell/3h). These results suggest that the ionic composition of culture media influences the in vitro development of cat IVF embryos. (Supported by NIH grant RR15388.)


2019 ◽  
Vol 31 (12) ◽  
pp. 1862 ◽  
Author(s):  
N. A. Martino ◽  
G. Marzano ◽  
A. Mastrorocco ◽  
G. M. Lacalandra ◽  
L. Vincenti ◽  
...  

Time-lapse imaging was used to establish the morphokinetics of equine embryo development to the blastocyst stage after invitro oocyte maturation (IVM), intracytoplasmic sperm injection (ICSI) and embryo culture, in oocytes held overnight at room temperature (22–27°C; standard conditions) before IVM. Embryos that developed to the blastocyst stage underwent precleavage cytoplasmic extrusion and cleavage to the 2-, 3- and 4-cell stages significantly earlier than did embryos that arrested in development. We then determined the rate of blastocyst formation after ICSI in oocytes held for 2 days at either 15°C or room temperature before IVM (15-2d and RT-2d treatment groups respectively). The blastocyst development rate was significantly higher in the 15-2d than in the RT-2d group (13% vs 0% respectively). The failure of blastocyst development in the RT-2d group precluded comparison of morphokinetics of blastocyst development between treatments. In any condition examined, development to the blastocyst stage was characterised by earlier cytoplasmic extrusion before cleavage, earlier cleavage to 2- and 4-cell stages and reduced duration at the 2-cell stage compared with non-competent embryos. In conclusion, this study presents morphokinetic parameters predictive of embryo development invitro to the blastocyst stage after ICSI in the horse. We conclude that time-lapse imaging allows increased precision for evaluating effects of different treatments on equine embryo development.


2009 ◽  
Vol 21 (1) ◽  
pp. 138
Author(s):  
J. R. Saenz ◽  
C. Dumas ◽  
B. L. Dresser ◽  
M. C. Gómez ◽  
R. A. Godke ◽  
...  

Our purpose was to compare in vitro survivability and functionality of cat epididymal spermatozoa cryopreserved in TEST egg-yolk buffered extender (TYB) with that obtained by use of clear Tris-citrate and HEPES-buffered extenders containing BSA. Testes were transported to the lab in HEPES saline; epididymides were dissected in HEPES-199 medium (HE-199) and repeatedly sliced. The sperm suspension was filtered (40 μm), layered onto a density gradient column (Isolater, Irving Scientific, Santa Ana, CA), and centrifuged at 600g for 20 min. Aliquots of the sperm pellet were extended in TYB, Human Sperm Preservation Medium (HSPM), or Tris-citrate + 10% BSA (TCBSA). After cooling to 4°C, samples were diluted 1:1 with extender + 12% glycerol in 4 steps as modified from Gao DY et al. 1995 Hum. Reprod. 10, 1109–1122. Then, samples were loaded into 0.25-mL straws, sealed, and frozen on a dry ice block (–80°C) for 20 min before storage in LN2. Straws were thawed by exposure to air (22°C) for 5 s and immersion in a 60°C water bath for 5 s. Samples were diluted by addition of HE-199 in 7 steps as modified from Gao DY et al. 1995 Hum. Reprod. 10, 1109–1122, centrifuged at 200g for 10 min and pellets resuspended in HE-199. Motility (MOT, phase contrast, 37°C), membrane integrity (MI, SYBR 14–PI), and acrosomal status (AS, FITC–PNA) were evaluated at 0 h, after gradual cooling to 4°C, and after freezing at 0 h and 3 h post-thaw (37°C). Cumulus oocyte complexes (COC) were placed in modified TCM-199 and cultured for 24 h in 5% O2, 5% CO2, and 90% N2 at 38°C (IVM). For IVF, COC were co-incubated with spermatozoa frozen in either TYB or HSPM in droplets (1 million sperm mL–1) of IVF medium under 5% CO2 in air at 38°C. After 18 h, oocytes were rinsed and cultured using a 3-step system (Pope CE et al. 2006 Theriogenology 66, 59–71) until blastocyst development was evaluated (Day 8). There were no treatment differences at any time/temperature point for the 3 sperm parameters evaluated (one-way ANOVA; P > 0.05). As shown in Table 1, sperm motility in TCBSA and HSPM decreased by 20% after cooling to 4°C and another 20% after freezing, whereas motility in TYB was maintained after cooling and decreased <30% after freezing. Membrane integrity and acrosomal status values were 12 to 15% greater at collection, at 4°C and at 0 h post-thaw, and 25% greater at 3 h post-thaw than were the motility values. Cleavage frequency and blastocyst development rate of 203 IVM oocytes after IVF using sperm frozen in TYB and HSPM was 36 v. 33% and 50 v. 44%, respectively. In summary, we have shown that cat epididymal spermatozoa can be frozen successfully in cryoprotectant solutions that do not contain egg yolk. Table 1.Motility, membrane integrity and acrosomal status of cat epididymal sperm after cryo-storage


2010 ◽  
Vol 22 (1) ◽  
pp. 214
Author(s):  
J. R. Saenz ◽  
C. Dumas ◽  
B. L. Dresser ◽  
M. C. Gómez ◽  
R. A. Godke ◽  
...  

Our purpose was to examine the effect of egg yolk concentration (EY; 2, 5, or 10%) on in vitro survivability and functionality of cat epididymal spermatozoa cryopreserved in TEST-buffered extender (TYB). Testes were transported in HEPES saline; epididymes were dissected in HEPES 199 medium (He199) and repeatedly sliced. The sperm suspension was filtered (40 μ), layered onto a density gradient column (Isolate®, Irving Scientific, Santa Ana, CA, USA), and centrifuged at 650 g for 20 min. Aliquots of the sperm pellet were extended in TYB containing 2, 5, or 10% EY. After cooling to 4°C, samples were diluted 1:1 with TYB containing 2, 5, or 10% EY + 12% glycerol in 4 steps as modified from Gao DY et al. Hum. Reprod. 1995 10, 1109-1122. Then, samples were loaded into 0.25-mL straws, sealed, and frozen on a dry ice block (-80°C) for 20 min before storage in LN2. Straws were thawed by exposure to air (˜22°C) for 5 s and immersion in a 60°C water bath for 5 s. Samples were diluted by addition of He199 in 7 steps as modified from Gao DY et al. Hum. Reprod. 1995 10, 1109-1122 centrifuged at 200g for 10 min, and pellets resuspended in He199. Motility (Mot, phase contrast, 37°C), membrane integrity (M.I., SYBR 14-PI), and acrosomal status (A.S., FITC-PNA) were evaluated at 0 h, after gradual cooling to 4°C and after freezing at 0 and 3 h post-thaw (37°C). Ten replicates were done. Cumulus oocyte complexes (COC) were placed in modified TCM-199 and cultured for 24 h in 5% O2, 5% CO2, and 90% N2 at 38°C (IVM). For IVF, COC were co-incubated with spermatozoa frozen in TYB + 2% egg yolk or HSPM (no egg yolk) in droplets (1 million sperm/mL) of IVF medium under 5% CO2 in air at 38°C. After 18 h, oocytes were rinsed and cultured until blastocyst development was evaluated (Day 8). There were no treatment differences at any time or temperature point for the 3 sperm characteristics evaluated (one-way ANOVA; P > 0.05). As shown in the Table 1, at 0 h post-thawing, sperm in each group retained ˜70% of their initial pre-freeze motility. After 3 h of post-thaw incubation, motility decreased to ˜50% of the pre-freeze value. Cooling to 4°C did not affect membrane integrity or acrosomal status, but post-thaw values were reduced by 30-35% as compared with pre-freeze. Cleavage frequency and blastocyst development of 284 IVM oocytes after IVF using sperm frozen in TYB + 2% EY and HSPM were 53 v. 52% and 42 v. 38%, respectively (P > 0.05). In summary, we have shown that cat epididymal spermatozoa can be frozen successfully in a cryoprotectant solution containing minimal egg yolk (2%). Table 1.Motility, membrane integrity, and acrosomal status of cat epididymal sperm after cryo-storage


2018 ◽  
Vol 30 (1) ◽  
pp. 188
Author(s):  
M. Duque ◽  
A. Sestelo ◽  
D. F. Salamone

The Puma concolor population has been decreasing during the last 30 years. Semen cryopreservation of this species has been accomplished successfully and offers the possibility of preserving endangered species. We previously showed that fertilizing capability of wild felid spermatozoa can be evaluated using intracytoplasmic sperm injection (ICSI) with in vitro-matured domestic cat oocytes (Moro et al. 2014 Reprod. Domest. Anim. 49, 693-700). Due to the lack of homologous oocytes, we evaluated the capability of the Puma concolor sperm to induce domestic cat oocyte fertilization and subsequent pre-implantation embryo development. In the present study, cryopreserved sperm obtained by electroejaculation from five different males were used for IVF of in vitro-matured (IVM) domestic cat oocytes. Straws were thawed by exposing them to air for 10 s and then immersing in a 37°C water bath for 30 s. The contents of the straws were poured into a sterile 1.5-mL microtube pre-warmed to 37°C. The sperm suspension was diluted (1:3 v/v) by the slow (drop-by-drop) addition of a modified Tyrode’s solution. For IVF, IVM oocytes (n = 370) were co-incubated with 0.5 × 105 motile spermatozoa mL−1 in an atmosphere of 21% O2 in air at 38.5°C for 18 to 20 h. Presumptive zygotes were cultured in vitro in 50-μL drops of modified Tyrode’s medium on 6.5% CO2 in air at 38.5°C. Cleavage was determined at 48 h post-fertilization, and 5% FBS was added at Day 5 of in vitro culture. Blastocyst stage was evaluated at Day 8. Results (mean ± SEM) showed a high cleavage rate (179/370, 49.0 ± 4.0%), and a high development to morula stage (137/370, 34.4 ± 7.2%), and to blastocyst stage (94/370, 23.4 ± 4.7%) for all males. These results indicated that Puma concolor spermatozoa can induce domestic cat oocyte activation and development to blastocyst stage in similar rates to domestic cat homologous IVF: IVM oocytes (n = 291), cleavage rate (199/291, 67.1 ± 6.1%), development to morula stage (144/291, 47.8 ± 4.9%), and to blastocyst stage (86/291, 30.1 ± 1.6%). In conclusion, we demonstrated that domestic cat oocyte can be used to evaluated cryopreserve sperm samples from another felid species.


2019 ◽  
Vol 31 (1) ◽  
pp. 178
Author(s):  
A. J. Sestelo ◽  
M. D. Rodriguez ◽  
N. Gañan ◽  
D. F. Salamone ◽  
L. Barañao ◽  
...  

Even though knowledge in sperm cryopreservation of endangered felids advanced in recent years, very little is known about suitable protocols to cryopreserve sperm from Leopardus geoffroyi (LG). In the present study, sperm obtained by electroejaculation from 5 different males were cryopreserved in either a Tes-Tris- or a lactose-based diluent (Gañan et al. 2009 Theriogenology 72, 341-352) with modifications in the freezing process using a one-step method: straws were placed horizontally on a metal rack, 4cm above the surface of liquid nitrogen in a styrofoam box, and kept for 10min before plunging them in LN. The objectives were to (1) compare in vitro motility and acrosome status of LG sperm cryopreserved in both extenders and (2) test functionality of LG sperm cryopreserved in both extenders through their ability to fertilize mature domestic cat oocytes. Straws were thawed by exposing them to air for 10s and then immersing them in a water bath at 37°C for 30s. The contents of the straws were poured into a sterile 1.5-mL microtube prewarmed to 37°C. The sperm suspension was diluted (1:3 vol/vol) by the slow (drop by drop) addition of a modified Tyrode’s solution. Sperm parameters, percentage of motile spermatozoa, and quality of motility were assessed and sperm motility index (SMI) was calculated as follows: [% motile sperm+(quality×20)]/2. Acrosome integrity was assessed by staining with Coomassie brilliant blue. For IVF, in vitro-matured domestic cat oocytes (n=238 Tes-Tris, n=239 lactose) were co-incubated with 0.5×105 motile spermatozoa/mL under 5% CO2 in air at 38.5°C for 18-20h (Pope et al. 2006 Methods Mol. Biol. 254, 227-244). Presumptive zygotes were cultured in vitro in 50-µL drops of modified Tyrode’s medium at 38.5°C in 5% CO2, 5% O2, 90% N2 atmosphere. Cleavage was assessed 48h postfertilization, and 5% FBS was added at Day 5 of in vitro culture. Blastocyst stage was evaluated at Day 8. Data was analysed by Fisher’s exact test using GraphPad Prism 6.0 (GraphPad Inc., San Diego, CA, USA), significant at P&lt;0.05. Results, mean (±standard error of the means), showed that SMI and acrosome integrity (pre- and post-thawing) were similar for both extenders: prethawed (SMI=56±3.3v. 59±5.5; acrosome integrity=88±3.0% v. 90±2.0%), and post-thawed (SMI=46±5.0v. 44±7.0; acrosome integrity=57±7.5% v. 68±2.4%) Tes-Tris v. lactose, respectively. For IVF, results showed a high cleavage rate in both groups (117/238, 49% v. 117/239, 49%), and a high development to morula (96/238, 40% v. 94/239, 39%) and to the blastocyst stage (61/238, 26% v. 51/239, 21%) for all males Tes-Tris v. lactose, respectively. There were no significant differences between groups at any development stage. In conclusion, we found that both extenders can be used to cryopreserve LG sperm maintaining functional conditions and that fertilizing capacity can be tested using in vitro-matured domestic cat oocytes.


2004 ◽  
Vol 16 (2) ◽  
pp. 157
Author(s):  
K. Saeki ◽  
T. Tamari ◽  
A. Kasamatsu ◽  
K. Shirouzu ◽  
S. Taniguchi ◽  
...  

During embryo development, embryonic gene activation (EGA) is one of the first critical events. Inappropriate EGA results in failure of further development. We have reported that gene expression in bovine embryos reconstructed with fibroblasts begins at 48 hours postfusion (hpf) and reaches a maximum level at 60hpf as detected by their bioluminescence following injection of chicken β-actin/firefly luciferase fusion gene (β-act/luc+) into their nuclei (Saeki et al., 2001 Theriogenology 55, 289). In the present study, effects of gene expression in embryos reconstructed with bovine fibroblasts transfected with luciferase gene on their subsequent development to the blastocyst stage were examined. Cultured bovine fibroblasts taken from an ear of a female calf were transfected with plasmid containing β-act/luc+/IRES/EGFP and neor using GeneJammer (StrataGene, La Jolla, CA, USA). Neomycin-resistant cells were selected by culturing with G418. Then, EGFP-positive colonies were further selected under fluorescence microscopy to obtain stably transfected cells. The transfected cells were cultured for several passages. Growing (50 to 60% confluence, GCs) and serum-starved cells (SCs) were used as donor cells. In vitro-matured bovine oocytes derived from slaughterhouse ovaries were enucleated at 20h post maturation. Enucleated oocytes were electrofused with the cells, and activated with calcium ionophore and cycloheximide. Luminescence in the embryos was detected with an imaging photon counter at 0 and 60hpf. Luminescence-positive (P) and -negative (N) embryos were cultured separately at each detection time. Embryos were cultured until 168hpf, and examined for cleavage and blastocyst development. Experiments were repeated 3 times, and totals of 91 and 123 embryos were reconstructed with GCs and SCs, respectively. Data were analyzed with Fisher’s PLSD test following ANOVA by Stat View software (Ver. 5.0). At 0hpf, luminescence was detected in 55 and 4% of embryos reconstructed with GCs and SCs, respectively. At 60hpf, luminescence was detected in 47 and 28% of P and N embryos with GCs, and 17 and 40% of P and N embryos with SCs at 0hpf, respectively. Cleavage rates were not different among groups (P&gt;0.05). Blastocysts were obtained only from the groups of embryos that were N at 0hpf and P at 60hpf (8% with GCs and 17% with SCs). No embryos in the other groups developed to the blastocyst stage. These results suggest that appropriate gene expression in embryos reconstructed with somatic cells is important for their subsequent development and that detecting the reporter gene expression can be used for selection of viable cloned embryos.


2004 ◽  
Vol 16 (2) ◽  
pp. 282 ◽  
Author(s):  
Z. Roth ◽  
P.J. Hansen

Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that can block the sphingomyelin cell-death pathway by suppressing ceramide-induced apoptosis. The present study was performed to test whether S1P protects oocytes from heat shock during in vitro maturation. Cumulus-oocyte complexes obtained by slicing follicles were placed in maturation medium with or without 50nM S1P and cultured at 38.5°C (CON) or 41°C (41C) for the first 12h of maturation. Incubation during the last 10h of maturation (22-h total maturation time), fertilization, and embryonic development were performed at 38.5°C and 5% (v/v) CO2. Blastocyst development was recorded at 8 days post-insemination (dpi) and activity of group II caspases in 8-day blastocysts was determined using a fluoroprobe, PhiPhiLux-G1D2 (OncoImmunin, Gaithersburg, MD, USA). Data were analysed by least-squares ANOVA with the GLM procedure of SAS. Percentage data were subjected to arcsin transformation before analysis. Exposure of oocytes to thermal stress during the first 12h of maturation reduced cleavage rate (P&lt;0.01) and the number of oocytes developing to the blastocyst stage (P&lt;0.04). There was a temperature x S1P interaction for cleavage rate (P&lt;0.03) because S1P blocked effects of thermal stress on cleavage rate. Without S1P, the percentage of oocytes that cleaved by 3 dpi were 83.6±2.7% and 65.8±2.7% for CON and 41C, respectively. In the presence of S1P, percent cleavage was 86.7±2.7% and 83.9±2.7% for CON and 41C, respectively. There was a trend (P=0.06) for a temperature x S1P interaction for percent oocytes developing to blastocyst stage because S1P blocked effects of heat shock on development. Without S1P, the percentages of oocytes that developed to the blastocyst stage were 28.7±3.0% and 15.2±3.0% for CON and 41C, respectively. In the presence of S1P, percent blastocysts were 24.3±3.4% and 23.9±3.0% for CON and 41C, respectively. When development was expressed as percentage of cleaved embryos, however, there were no effects of temperature, S1P, or temperature x S1P on percent development to the blastocyst stage. Blastocyst caspase activity was not affected by temperature or S1P. In summary, exposure to physiologically relevant thermal stress during the first 12h of maturation has a deleterious effect on oocyte competence and this effect can be reduced by S1P. The fact that heat shock reduced the percentage of oocytes but not the percentage of cleaved embryos that became blastocysts suggests that oocytes that survive effects of heat shock and cleave have normal potential to develop to the blastocyst stage. Moreover, since heat shock did not affect caspase activity, it is likely that blastocysts from heat-shocked oocytes have normal developmental potential, at least as determined by caspase activity. Support: BARD FI-330-2002 and USDA Grants 2002-35203-12664 and 2001-52101-11318.


2007 ◽  
Vol 19 (1) ◽  
pp. 173 ◽  
Author(s):  
J. Braun ◽  
C. Otzdorff ◽  
T. Tsujioka ◽  
S. Hochi

The effects of slow freezing or vitrification as well as exposure to the cryoprotective media without cooling and warming of in vitro-matured domestic cat oocytes on the in vitro development to the blastocyst stage was investigated. Cumulus–oocyte complexes were matured for 24 h in TCM-199 supplemented with 3 mg mL−1 BSA, 1 µg mL−1 estradiol, 0.1 IU mL−1 FSH, and 0.0063 IU mL−1 LH. Denuded oocytes with a detectable first polar body were inseminated with 2 × 106 cells mL−1 cauda epididymal spermatozoa for 22 h in TALP solution. Presumptive zygotes were cultured in modified SOF medium at 38.5°C in 5% CO2 in air. For slow freezing, oocytes were equilibrated for 20 min at ambient temperatures in PBS with 20% FCS containing either 1.5 M ethylene glycol (EG) + 0.2 M sucrose or 1.5 M EG + 0.2 M trehalose. Oocytes were loaded into 0.25-mL straws, cooled to −7°C at 2°C min, held for 5 min, seeded, cooled down to −30°C at 0.3°C min, and finally plunged into liquid nitrogen. The straws were thawed for 5 s at room temperature and for 30 s in a waterbath at 30°C. Oocytes were washed 3 times before insemination. In vitro-matured oocytes were exposed to the cryoprotective media for 30 min before they were inseminated and then they were cultured for 7 days. For vitrification (Hochi et al. 2004 Theriogenology 61, 267–275), a minimum-volume cooling procedure using Cryotop (Kitazato Supply Co., Tokyo, Japan) as a cryodevice was applied. No blastocysts could be obtained after slow freezing with a cryoprotective medium containing 0.2 M sucrose. Simple exposure to the same freezing medium after in vitro maturation without cryopreservation resulted in a blastocyst rate of 7.9% (control oocytes, 10.7%; not significant (NS); chi-square analysis). Use of trehalose as an extracellular cryoprotectant resulted in the harvest of one blastocyst (0.6%) after slow freezing. Exposure to the same cryoprotective medium resulted in a blastocyst rate of 10.0% (fresh control, 10.9%; NS). After exposure of in vitro-matured oocytes to the vitrification solution, a blastocyst rate of 16.0% was observed (8/50), which was not statistically different from the blastocyst rate in fresh control oocytes (16.3%; 15/92). No blastocysts could be obtained after vitrification (0/64). The results (Table 1) demonstrate that there is no obvious toxic effect of the cryoprotectants employed here for slow freezing or vitrification on the in vitro-matured oocytes, but the developmental potential of cryopreserved oocytes to the blastocyst stage is severely impaired. Table 1. Effect of slow freezing or exposure to freezing medium of matured cat oocytes on the development to the blastocyst stage in vitro


2006 ◽  
Vol 18 (2) ◽  
pp. 247 ◽  
Author(s):  
K. Kikuchi ◽  
M. Nakai ◽  
N. Kashiwazaki ◽  
M. Ozawa ◽  
N. Maedomari ◽  
...  

The utilization of spermatogonia from testicular tissue after xenografting into immuno-deficient mice should lead to new insights for the conservation of male gametes. However, successful embryo production using sperm cells from xenografted testicular tissues has been limited to rhesus monkeys (Honaramooz et al. 2004 Biol. Reprod. 70, 1500-1503). In the present study, the objective was to establish this new technology for pig conservation in combination with intracytoplasmic sperm injection. Testes were obtained from male piglets 6 to 15 days old, in which most of the germ cells were gonocytes; these were minced into pieces of approximately 1.5 � 1.5 � 1.5 mm. Approximately 20 fragments were transplanted under the back skin of castrated nude mice 5 to 8 weeks old. The testicular grafts were recovered between 125 and 192 days after xenografting, minced in Dulbecco's phosphate-buffered saline, and centrifuged several times, to serve as a sperm suspension. In vitro maturation of the recipient oocytes (Kikuchi et al. 2002 Biol. Reprod. 66, 1033-1041) and injection with an intact spermatozoon, followed by electrical stimulation at 1 h post-injection (Nakai et al. 2003 Biol. Reprod. 68, 1003-1008), were carried out. The putative zygotes were cultured in vitro for 6 days (Kikuchi et al. 2002), and were then fixed, stained, and assessed for embryonic development and quality. From a total of 27 mice that were xenografted with testicular tissues, spermatids and spermatozoa were obtained in 19 of the mice (70.4%). Most of the spermatozoa were matured morphologically, showing faint motility after release into the collection medium. From a total of 253 oocytes (four replications) that were injected with sperm, 63 (24.9 � 7.1%) oocytes developed to the blastocyst stage. The average total cell number was 41.9 � 3.9. These values are comparable to those in in vitro fertilization by frozen-thawed spermatozoa, resulting in developmental ability to piglets after embryo transfer (25.3% and 48.7 cells; Kikuchi et al. 2002). These results suggest the possibility of embryo production using porcine spermatozoa that are differentiated from gonocytes within the xenografts.


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