76 SURVIVAL AND IN VITRO FUNCTIONALITY OF DOMESTIC CAT EPIDIDYMAL SPERMATOZOA FOLLOWING CRYOPRESERVATION IN EXTENDERS WITH OR WITHOUT EGG YOLK

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


2012 ◽  
Vol 24 (1) ◽  
pp. 139
Author(s):  
J. R. Saenz ◽  
C. Dumas ◽  
B. L. Dresser ◽  
M. C. Gómez ◽  
R. A. Godke ◽  
...  

Previously, we have shown that survival of cat sperm is maintained in both non-egg yolk, semi-defined extenders and in extenders with greatly reduced levels of egg yolk (2%). Usually, cryoprotectant is added to extended samples after gradual cooling to 4°C, but recent reports have shown that satisfactory sperm survival can be obtained after addition at 22°C. Here, our objectives were to examine sperm survival after (1) cryopreservation from 22°C vs after gradually cooling to 4°C or (2) cryopreservation in a completely defined extender without animal or plant proteins vs extender + 2% egg yolk. Epididymides from local veterinary clinics were dissected in HEPES 199 medium (He199). The sperm suspension was filtered (40 μ), layered onto a density gradient column and centrifuged at 650 × g for 20 min. Then, the sperm pellet was resuspended in 1 mL of He199 and centrifuged for 5 min at 800 × g and the subsequent pellet was extended in TEST Buffer with either 0% (0% EY) or 2% egg yolk (2% EY). Next, 0% EY samples were further split into 2 groups—either gradually cooled to 4°C before 12% glycerol (1:1) was added (4C-0%EY) or 12% glycerol (1:1) was added at 22°C without cooling (22C-0%EY). Control samples extended in 2% EY were cooled to 4°C before addition of 12% glycerol (1:1) (4C-2%EY). Samples were loaded into 0.25-mL straws and placed in a –80°C freezer for 20 min before storage in LN2. Sperm samples were thawed in air (22°C) for 5 s and immersed in a 60°C water bath for 5 s. After a 7-step addition of He199, samples were centrifuged at 800 × g for 5 min and pellets resuspended in He199. Sperm samples were evaluated for motility (Mot; computer-assisted semen analysis, 37°C) at 0 h (initial assessment), after cooling to 4°C (PC) and at 0-h (0-PT) and 3-h post-thaw (3-PT) incubation at 37°C. Membrane integrity (MI; SYBR 14-PI) and acrosomal status (AS; FITC-PNA) were analysed at the initial assessment, 0-PT and 3-PT. Results are shown in Table 1. At 4°C (PC), sperm extended in 0% EY and 2% EY maintained 92 and 91%, respectively, of their initial motility (66%). At 0-PT and 3-PT, motility in the 3 groups had decreased by >50% and >70%, respectively. Motility at 3-PT in the 22C-0%EY treatment was less than the other 2 treatments (P < 0.05; 1-way ANOVA). At 0-PT, samples in the 4C-2%EY group had a higher membrane integrity value (P < 0.05) than did the 22C-0%EY group, whereas that of the 4C-0%EY group was not different from the other 2 groups. However, at 3-PT, both groups cooled to 4°C before cryopreservation had higher membrane integrity values (P < 0.05) than the group cryopreserved at 22°C. At 0-PT and 3-PT, the percentage of sperm with intact acrosomes ranged from 69% (4C-2%EY) to 59% (22C-0%EY) and from 55% (4C-2%EY) to 43% (22C-0%EY) of the initial value (89%), respectively. In summary, we demonstrated that cat epididymal sperm could be frozen successfully in a completely defined TEST-buffered extender. Furthermore, we confirmed that addition of cryoprotectant (i.e. glycerol) after gradual cooling to 4°C is beneficial to post-thaw survival. Table 1.Motility (Mot), membrane integrity (MI) and acrosomal status (AS) of cat epididymal sperm before and after cryostorage


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.


2011 ◽  
Vol 23 (1) ◽  
pp. 150
Author(s):  
J. R. Saenz ◽  
C. Dumas ◽  
B. L. Dresser ◽  
M. C. Gómez ◽  
R. A. Godke ◽  
...  

A general objective of our studies on cat sperm is to enhance methods for both short- (+4°C) and long-term (–196°C) cryostorage, with particular focuses on improving compatibility with sex sorting and conforming to regulations for international shipment. Here, our specific aims were to a) determine the ability of cat sperm to survive during temporary cool storage in defined extenders (Exp. 1), and b) compare sperm survival after cryopreservation in the optimal defined extender v. TEST buffered extender + 2% egg yolk (TYB, Exp. 2). Testes from local veterinary clinics were transported in HEPES saline. Epididymides were dissected in HEPES 199 medium (He199), repeatedly sliced, and held at 37°C for ∼20 min. The sperm suspension was filtered (40 μm), layered onto a density gradient column (Isolate®, Irving Scientific, Santa Ana, CA, USA), and centrifuged at 650 × g for 20 min. Then, the sperm pellet was resuspended in 1 mL He199 and centrifuged for 5 min at 250 × g. In Exp. 1 (5 replicates), aliquots of the sperm pellet were extended in either of 2 defined extenders, Bioxcell® (BXC; IMV, Minneapolis, MN, USA) or HypoThermosol®-FSR (HTS; BioLife Solutions Inc., Bothell, WA, USA) or in TYB. Motility (Mot, Hamilton Thorne Sperm Analysis System CEROS 12, 37°C), membrane integrity (M.I., SYBR 14-PI), and acrosomal status (A.S., FITC-PNA) were evaluated at days 0, 1, 2, and 3 (Exp. 1), or after cooling (4°C) and post-thawing (p.t.), after 0 and 3 h incubation at 37°C (Exp. 2). In Exp. 2 (10 replicates), the sperm pellet was extended in BXC or TYB and gradually cooled to 4°C. Then, BXC or TYB + 12% glycerol was added (1:1) using a modified fixed osmolarity method (1995 Hum. Reprod. 10, 1109). Samples were loaded into 0.25-mL straws and frozen on a dry ice block (–80°C) for 20 min before storage in LN2. Straws were thawed in air (∼22°C) for 5 s and immersed in a 60°C water bath for 5 s. Samples were diluted by addition of He199 in 7 steps, centrifuged at 800 × g for 5 min, and pellets resuspended in He199. In Exp. 1, sperm in TYB, BXC, and HTS maintained 93, 69, and 56%, respectively, of initial motility (71%) after 3 days at 4°C (TYB > BXC and HTS; P < 0.05, 1-way ANOVA). Initially, 75 and 86% of sperm had membrane integrity and intact acrosomes, respectively. At 72 h, ∼80% of membrane intact sperm retained integrity in the two defined extenders v. nearly 90% in TYB (P > 0.05). At 24 h, all groups had high percentages of sperm with intact acrosomes (87 to 93%), but at 72 h, there was a difference between HTS (96%) and BXC (79%; P < 0.05). In Exp. 2 (Table 1), motility in TYB and BXC at 0 h p.t. was 77 and 70% of pre-freeze values – 77% (TYB) and 73% (BXC), respectively. Motility at 3 h p.t. was similar (BXC = 35% v. TYB = 37%). Membrane integrity and acrosomal status at 3 h p.t. ranged from 60% (BXC) to 72% (TYB) and from 65% (BXC) to 68% (TYB) of pre-freeze values, respectively. At 3 h p.t. M.I. of sperm in TYB was higher (P < 0.05) than in BXC. In summary, we have shown that cat epididymal sperm can be stored temporarily and cryopreserved successfully in a defined extender without animal proteins. Table 1.Motility, membrane integrity, and acrosomal status of cat epididymal sperm after cryo-storage


2008 ◽  
Vol 20 (1) ◽  
pp. 213 ◽  
Author(s):  
C. E. Pope ◽  
E. B. Crichton ◽  
M. C. Gmez ◽  
C. Dumas ◽  
B. Dresser

In cats, sex selection by fertilization of oocytes with sperm sorted into X- andY-chromosome-bearing populations has credible biomedical, commercial, and conservation connotations. Our objectives were (1) to evaluate the efficiency with which embryos could be produced by IVF of in vivo- and in vitro-matured oocytes with cooled sex-sorted sperm after overnight shipment to the sorting facility and overnight return delivery to an IVF laboratory, and (2) to determine if live kittens of predetermined sex (female) could be produced after transfer of embryos derived by IVF of in vivo-matured oocytes with X-chromosome-bearing sperm to recipient females. Semen samples (n = 5) collected from a single male using an artificial vagina were extended in electrolyte-free solution (glucose–BSA) and shipped overnight in an Equitainer (4�C) to the sorting facility. Upon arrival, sperm were stained (9 µm Hoechst 33 342; 75 � 106 sperm mL–1), adjusted to 50 � 106 sperm mL–1 with 4% egg yolk TALP containing 0.002% food dye, and sorted on an SX MoFlo� flow cytometer (Dako, Fort Collins, CO, USA). Purities from resort analysis averaged 94% (X) and 83% (Y). After sorting, sperm were concentrated by centrifugation, suspended in TEST-yolk buffer (Irvine Scientific, Santa Ana, CA, USA), and return-shipped to the IVF lab where they were received 48 h after collection. In vivo-matured oocytes recovered from gonadotropin-treated donors were inseminated in vitro with X-chromosome-bearing sperm. In vitro-matured oocytes obtained from ovaries donated by local clinics were inseminated in vitro with control (cooled/shipped/non-sorted) or X- orY-chromosome-bearing sperm. At 5 h or 18 h post-insemination, in vivo- and in vitro-matured oocytes, respectively, were rinsed and placed in IVC-1 medium (Pope et al. 2006 Theriogenology 66, 59–71). Embryos produced from in vitro-matured oocytes were allowed to develop until Day 8 in a three-step culture system (Pope et al. 2006). Cleavage frequency of in vitro-matured oocytes after insemination with X-, Y-, and control sperm was 33% (40/120), 35% (52/150), and 42% (48/115), and blastocyst development was 50% (11/22), 55% (23/42), and 53% (21/40), respectively (P > 0.05). Incidence of cleavage after insemination of in vivo-matured oocytes with X-sperm was 62% (54/87). On Day 2, 45 embryos (9–16 per recipient) produced by in vitro insemination of in vivo-matured oocytes with X-sperm were transferred by laparoscopy to the oviducts of four Day 1 gonadotropin-treated recipients. Three recipients established pregnancies and delivered litters of one, four, and seven female kittens between Day 62 and Day 66 of gestation. We have demonstrated that sperm-sorting technology can be applied and used effectively in domestic cats and, potentially, should be relevant to the selective breeding of endangered cats.


Zygote ◽  
2009 ◽  
Vol 18 (1) ◽  
pp. 1-8 ◽  
Author(s):  
N. Cocchia ◽  
F. Ciani ◽  
R. El-Rass ◽  
M. Russo ◽  
G. Borzacchiello ◽  
...  

SummaryCryopreservation of gametes is an important tool in assisted reproduction programmes; long-term storage of oocytes or spermatozoa is necessary when in vitro fertilization (IVF) or artificial insemination is to be performed at a future date. Cryopreservation of epididymal spermatozoa offers a potential tool for rescuing genetic material from males of endangered populations. The objectives of this work were to: (1) examine sperm motility, viability, abnormality and acrosome integrity of frozen–thawed domestic cat epididymal spermatozoa; and (2) evaluate the same cryopreservation method on wild feline spermatozoa, needed to preserve their genetic resources. Epididymides were collected from 20 domestic cats during routine neutering procedure and from two wild felines at autopsy. The sperm samples, diluted with 4% glycerol/Tris/egg yolk, were loaded into 0.25 ml mini-straws, exposed to nitrogen vapour and stored in liquid nitrogen. After 4 weeks, samples were thawed and re-evaluated. The quality of each fresh and frozen–thawed sperm sample was tested by determining the motility (54.7 ± 11.3% and 32 ± 13.1% respectively for cat spermatozoa; 38.3 ± 18.7% and 21.5 ± 16.8% respectively for tiger spermatozoa), viability (74.3 ± 8.6% and 45.2 ± 9.4% respectively for cat spermatozoa; 42.4 ± 14.5% and 33.5 ± 12.9% respectively for wild felid spermatozoa), morphology and acrosomal status. The present study showed that feline epididymal spermatozoa can be frozen in egg-yolk extender with 4.0% glycerol in 0.25 ml straws. The procedure used in the present study for epididymal cat sperm cryopreservation may be applied to bank the genetic resources of wild felid species.


2004 ◽  
Vol 16 (2) ◽  
pp. 226 ◽  
Author(s):  
F. Martinez-Pastor ◽  
F. Olivier ◽  
T. Spies ◽  
L. Anel ◽  
P. Bartels

Biological Resource Banks represent a potentially valuable tool for species conservation. It is, however, necessary to understand the species-specific cryopreservation process and its consequences for spermatozoa to aid in the development of assisted reproduction as a future conservation tool. The aim of this study was to assess the in vitro functionality of white rhinoceros Cerathoterium simum epididymal spermatozoa both before and after cryopreservation. Testes from a harvested white rhino bull were removed and transported at 5°C to the laboratory within 4h. The cauda epididymis was dissected out and flushed with 2mL of Tris-citrate egg yolk extender (fraction A, Biladyl, Minitüb, Germany). A 0.1mL aliquot was removed for analysis and the balance (9mL; 2mL fraction A+7mL sperm sample) mixed with an additional 27.2mL of Tris-citrate egg yolk with glycerol (fraction B, Bidadyl). The extended sample was allowed to cool to 4°C over a 6-h period before an additional 29.2mL of cooled fraction B were added (final sperm concentration=150×106mL−1). Sperm samples were loaded into 0.25-mL straws and frozen over LN2 vapor (4cm for 20min) for later assessment. Sperm straws were thawed by placing the straws in water at 37°C for 30s. Pre-freeze and post-thaw evaluations were carried out in the same manner. Media used included: HEPES for washing (20mM HEPES, 355mM sucrose, 10mM glucose, 2.5mM KOH) and HEPES saline (197mM NaCl, instead of sucrose). An aliquot was diluted with HEPES (washing) and centrifuged for 5min at 600×g; the pellet was resuspended in HEPES saline. Sperm motility (total motility %, TM;; and progressive motility %, PM) was assessed using phase contrast microscopy (×200; 37°C). Sperm plasma membrane status was assessed using the fluorescent dye, propidium iodide (50ngmL−1 in HEPES saline;; 10min, RT). Percentage of cells with plasma membranes intact (unstained;; PMI) was recorded. Mitochondrial status was assessed with the fluorescent dye, JC-1 (7.5μM in HEPES saline;; 30min, 37°C). The % of cells with an orange-stained midpiece was recorded (active mitochondria;; MIT). Resilience to hypoosmotic shock (HOS test) was assessed by diluting a sample in 100mOsm/kg HEPES saline (1:20; 15min, RT). An aliquot was stained with PI to assess plasma membrane status (HOSPMI), and the rest was fixed with formaldehyde, and % coiled tails (positive endosmosis;; HOST) was estimated using phase contrast microscopy (×400). Evaluations of PMI, MIT and HOSPMI were performed using fluorescence microscopy (×400, 450–490nm excitation filter). The results indicated that quality was good pre-freezing (TM: 60%; PMI: 86%; MIT: 100%), except for a PM value of 15%. After thawing, although there was a drop in TM (30%), there was no decrease in PM (20%). Our in vitro functional assessment indicated a loss of quality between the pre-freeze and post-thaw evaluations, but PMI and MIT maintained their pre-thaw levels (60% and 72%, respectively). The HOS test, which indicates plasma membrane integrity, decreased from the pre-freeze level (91%) to a post-thaw value of 70%. HOSTPMI was 72% pre-freeze, and decreased to 54% post-thaw. In conclusion, epididymal spermatozoa from the white rhino may retain its functionality after cryopreservation in a commerically available cryo-extender (Bidadyl). The use of assisted reproduction techniques could someday play a role in the management and conservation of the white rhinoceros and related species.


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.)


1997 ◽  
Vol 9 (7) ◽  
pp. 697 ◽  
Author(s):  
Rupasri Ain ◽  
P. B. Seshagiri

The inßuence of the sperm motility stimulant pentoxifylline (PF) on preimplantation embryo development in hamsters was evaluated. Eight-cell embryos were cultured in hamster embryo culture medium (HECM)-2, with or without PF (0· 0233·6 mM). There was 90%, 37% and 29% inhibition of blastocyst development by 3·6 (used for human sperm), 0·9 and 0 ·45 mM PF, respectively. However, 23 µM PF (exposed to hamster oocytes during IVF) signicantly (P < 0·05) improved blastocyst development (63· 6% v. 51· 8%); morulae development was, however, not curtailed by 0·45 mM or 0·9 mM PF (51·8%±6·0 or 50·5%±11·3, respectively). Post-implantation viability of PF-treated embryos was assessed by embryo transfer; 43% of 80 PF-treated embryos implanted compared with 40% of 79 control embryos. Of the 9 recipients, 6 females delivered pups (19, i.e. 16% of transferred embryos or 53% of implanted embryos). These data show that in hamsters, continuous presence of PF at 0·45-3·6 mM is detrimental to 8-cell embryo development whereas 23 µM PF improves the development of embryos to viable blastocysts which produce live offspring.


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