The effect of protein supplementation on single-cell mouse embryos in vitro

A combination of hydroxypropyl cellulose and trehalose as supplementation for vitrification of human oocytes: a retrospective cohort study

PURPOSE

This study aimed to determine whether the new formulation of vitrification solutions containing a combination of hydroxypropyl cellulose (HPC) and trehalose does not affect outcomes in comparison with using conventional solutions made of serum substitute supplement (SSS) and sucrose.

METHODS

Ovum donation cycles were retrospectively compared regarding the solution used for vitrification and warming of human oocytes. The analysis included 218 cycles (N = 2532 oocytes) in the study group (HPC + trehalose) and 214 cycles (N = 2353 oocytes) in the control group (SSS + sucrose).

RESULTS

No statistical differences were found in ovarian stimulation parameters and baseline characteristics of donors and recipients. The survival rate was 91.3% (95% confidence interval (CI) = 89.8-92.9) in the HPC + trehalose group vs. 92.1% (95% CI = 90.4-93.7) in the SSS + sucrose group (NS). The implantation rate (42.8%, 95% CI = 37.7-47.9 vs. 41.2%, 95% CI = 36.0-46.4), clinical pregnancy rate (CPR) per transfer (60.7%, 95% CI = 53.9-67.5 vs. 56.4%, 95% CI = 49.3-63.5), and ongoing pregnancy rate (OPR) per transfer (48.5%, 95% CI = 41.5-55.5 vs. 46.3%, 95% CI = 39.2-53.4) were similar for patients who received either HPC + trehalose-vitrified oocytes or SSS + sucrose-vitrified oocytes. Statistical differences were found when analyzing blastocyst rate both per injected oocyte (30.2%, 95% CI = 28.3-32.1 vs. 24.1%, 95% CI = 22.3-25.9) and per fertilized oocyte (40.8%, 95%CI = 38.5-43.1 vs. 33.2%, 95% CI = 30.8-35.5) (P < 0.0001). Delivery rate was comparable between groups (37.2%, 95% CI = 30.8-46.6 vs. 36.9%, 95% CI = 30.4-43.4; NS).

CONCLUSIONS

Our data demonstrate that HPC and trehalose are suitable and safe substitutes for serum and sucrose. Therefore, the new commercial media can be used efficiently in the vitrification of human oocytes avoiding viral and endotoxin contamination risk.

Quality Management Issues in the Assisted Reproduction Laboratory

In the United States, the Clinical Laboratory Improvement Act (CLIA) of 1988 describes requirements and guidelines for implementing a quality control/quality assurance (QC/QA) program for moderate and high complexity laboratories. These requirements and guidelines apply to Assisted Reproductive Technology (ART) laboratories as well. The general topic of QC and QA as it pertains to in vitro fertilization (IVF) and embryo transfer (ET) is extensively reviewed. This review summarizes many of the QC and QA events that contribute to the advancement of knowledge in this biotechnological field. These events include control of the culture environment inside and outside of the incubator, as well as factors that affect culture media. This review also discusses, in considerable detail, the QC and the QA that pertain to equipment used within the laboratory and how to control for potential contaminants, which reside within the laboratory. This review provides evidence to indicate the need for laboratory personnel to monitor quality improvement issues on a continuous basis. Personnel must be willing to change as improvements in technology occur in order to meet the ever-evolving demands of a more difficult patient population. Suggestions for meeting these demands are offered.

Effect of medium conditioned with rat hepatoma BRL cells on '2-cell block' of random-bred mouse embryos cultured in vitro

The phenomenon of developmental arrest at the 2-cell stage of zygotes obtained from certain mouse strains during in vitro culture is known as the 2-cell block. The effect of conditioned medium (CM) with rat hepatoma BRL cells on the 2-cell block of CD-1 mouse zygotes was investigated in comparison with that of CM with rat hepatoma Reuber H-35 cells. In control medium with EDTA, 75.4% of 2-cell embryos developed to the 4- to 8-cell stages. In the same conditions, the BRL Mr <10000 fraction inhibited the development of 2-cell embryos to the 4- to 8-cell stages (57.7%), although the inhibition by this fraction was weaker than by the Reuber Mr <10000 fraction (19.8%). As a result of reversed-phase column chromatography, a 2-cell stage specific inhibitor of the cleavage of mouse embryos (Fr.B-25), which separated into the Mr <10000 fraction of the Reuber CM, was detected at a low level in the BRL Mr <10000 fraction. On the other hand, the Mr >10000 fraction of BRL CM accelerated the development of the embryos (90.3%). This beneficial effect was also evident even in the absence of EDTA. RT-PCR analysis revealed that mRNAs encoding the beta-A or beta-B subunit of activins (Mr ~29000), which are well characterized cytokines that act as releasers of the 2-cell block, were expressed in BRL cells. These results indicate that BRL cells synthesize Fr.B-25 at low levels, and that activins contained in the BRL CM probably contributed to overcoming the 2-cell block of CD-1 zygotes cultured in vitro.

Developmental competence and post-thaw survivability of buffalo embryos produced in vitro: effect of growth factors in oocyte maturation medium and of embryo culture system

The present study was conducted to examine the effects of supplementation to IVM medium of epidermal growth factor (EGF), fibroblast growth factor (FGF) and vasoactive intestinal peptide (VIP) along with pregnant mare serum gonadotrophin (PMSG) on oocyte maturation and cleavage of buffalo embryos (experiment 1). The developmental competence of cleaved embryos cultured in either a complex co-culture system (TCM-199+10% serum+oviduct cell monolayer) or defined media (a) modified form of synthetic oviductal fluid (mSOF) was evaluated (experiment 2). The post-thaw morphology and survivability of frozen blastocysts developed from embryos cultured either in complex or defined medium was compared (experiment 3). Aspirated oocytes were cultured in maturation medium (TCM-199+PMSG (40 IU/ml-control)) supplemented with EGF (20 ng/ml), FGF (20 ng/ml) and VIP (20 ng/ml), either alone or in combination, in a CO(2) incubator at 38.5 degrees C for 24h. Maturation rate was assessed and oocytes were inseminated in vitro with frozen-thawed sperm processed in Brackett and Oliphant (BO) medium. The cleaved embryos were cultured either in complex co-culture system or mSOF. Results suggested that EGF had more beneficial effect on buffalo oocyte maturation, and embryo cleavage than FGF. Addition of VIP to the oocyte maturation medium did not improve the results. Blastocyst yields from buffalo oocytes were significantly higher in a complex co-culture system than in defined media (mSOF) when oocytes were matured in presence of EGF either alone or in combination with FGF and VIP. The mean percent of morphologically normal blastocysts after thawing and their survivability were significantly higher in blastocysts obtained from embryos cultured in mSOF than those cultured in complex co-culture system.

Manipulated mouse embryos as bioassay system for water quality control

Mouse pronuclear stage embryos with intact slit zona pellucida (manipulated) were cultured in vitro until the hatched blastocyst stage in simplex optimized medium with higher K+ concentration (KSOM) prepared with three different water types: tap, deionized reverse osmosis (D-O) water and Milli-Q system (M-Q) water. The culture media were supplemented with or without protein and ethylenediaminetetraacetic acid (EDTA, disodium salt). The rates of hatched blastocysts were significantly affected (p < 0.01) by micromanipulation, protein supplement and water source. The water source has no influence (p > 0.05) on development in EDTA-supplemented protein-free culture media, whereas in EDTA- and protein-free culture media, the water quality significantly (p < 0.001) affected the rates of development, with higher rates in media prepared with M-Q water. The micromanipulated embryos showed higher sensitivity to the water quality (p < 0.01). It worth mentioning that the rates of hatched blastocysts in protein-free culture media were very low (0-7.5%). Furthermore, the three different water types were analysed by measuring the electrical conductivity, inorganic ions, total organic carbon and endotoxins to evaluate the purity. M-Q water showed the lowest levels of inorganic ion, total organic carbon and endotoxin concentrations. We concluded that manipulated mouse embryos are good system to evaluate the quality of water used in biological system.

Effect of insulin, transferrin and selenium and epidermal growth factor on development of buffalo oocytes to the blastocyst stage in vitro in serum-free, semidefined media

The in vitro development of buffalo oocytes up to the blastocyst stage was studied in serum-free, semidefined media containing bovine serum albumin, follicle-stimulating hormone (FSH), insulin, transferrin and selenium (ITS) and epidermal growth factor (EGF). In experiment 1, oocytes aspirated from abattoir-derived ovaries were cultured in eight serum-free, semidefined culture media containing different combinations of these four factors. In experiment 2, the maturation of buffalo oocytes and the development of the embryos were compared in a complex co-culture system and in the serum-free, semidefined media. Supplementation with FSH and EGF significantly (P < 0.05) increased the maturation rates of buffalo oocytes, and the yield of blastocysts was higher (P < 0.05) in media containing EGF and ITS. The yield of blastocysts was lower in the serum-free semidefined media (P < 0.05) than in the complex co-culture system.

Globulins in protein supplements promote the development of preimplantation embryos

PURPOSE

Our purpose was to investigate the effect of alpha- and beta-globulins contained in protein supplements on the development of preimplantation embryos.

METHODS

Mouse one-cell embryos were cultured in medium supplemented with 4 mg/ml human serum albumin (HSA), 4 mg/ml HSA plus human globulins (0.2, 0.4, 0.8, and 1.6 mg/ml) that consisted predominantly of alpha- and beta-globulins, or 10% Plasmanate Cutter (PC). Blastocysts developed in media supplemented with these various protein sources were stained with Hoechst 33342 to determine the number of cells.

RESULTS

Supplementation with 0.4 to 1.6 mg/ml globulins or PC significantly increased the rate of blastocyst development compared with that observed with the addition of HSA. Supplementation with globulins significantly increased the hatching rate in a dose-dependent manner. The number of cells in the blastocysts was significantly increased when the embryos were cultured with 0.8 mg/ml of the globulins or PC.

CONCLUSIONS

The present observations suggest that alpha- and beta-globulins in protein supplements promote embryo development and hatching.

Assessment of the quality of frozen serum by spectrophotometric analysis and sperm bioassay

Serum is an integral part of media used for in vitro fertilization (IVF) and andrology work. Previous studies showed that the IVF results could benefit if sera were screened for deleterious effects before use. Such screening is impractical when fresh sera are used but may be feasible if the serum is frozen prior to use. This study assessed the impact of freezing on the quality of serum. A total of 158 serum samples, prepared in a university-based andrology-IVF center, were included in the study. The frozen sera were thawed in batches to be used in a series of laboratory experiments. Serum quality was evaluated by spectrophotometric analysis and sperm bioassay under several defined conditions: fresh, frozen, pre- and postfiltration, pre- and postcentrifugation, and the patients' fertility condition. Although all sera were filtered through 0.22-micron filter, more than 10% frozen sera required 0.4- or a combination of 0.8- and 0.4-micron filters before they could be passed through the 0.22-micron filter. Frozen sera that were directly filtrable with a 0.22-micron filter lost 13% turbidity upon filtration. The turbidity of the frozen sera were higher compared to fresh ones as revealed by optical density (OD) and relative light scattering (RLS) spectrophotometry. The freeze/storage-induced spectrophotometric changes did not correlate with the storage time. The centrifugation caused precipitation of sera components. The rate of precipitation of the serum components correlated with the duration of freezing. Spectrophotometric analysis and sperm bioassay did not differentiate the sera of pregnancy-positive and pregnancy-negative subjects. The sperm bioassay failed to detect any biological impact of freezing-induced spectrophotometric changes in the sera, suggesting that the freezing-induced changes did not significantly diminish the serum's capability of supplementing the culture media.

Globulin-enriched protein supplements shorten the pre-compaction mitotic interval and promote hatching of murine embryos

PROBLEM

To determine whether Synthetic Serum Substitute (SSS), which contains human globulins in addition to Human Serum Albumin (HSA), is superior to HSA alone as a protein supplement for embryo culture.

METHOD

Development of mouse zygotes to eight-cell/compacting morulae and to hatching/hatched blastocysts was assessed in Human Tubal Fluid (HTF) medium containing either SSS of HSA.

RESULTS

Although there was no difference in the overall blastocyst rate at 120 h in HTF+SSS versus HTF+HSA, significantly more embryos at 54 h were at the eight-cell/compacting morula stage in HTF+SSS. At 120 h, there were more hatching/hatched blastocysts in HTF+SSS, and hatching correlated with SSS concentration. Addition of isolated globulins to HSA significantly stimulated the number of hatching/hatched blastocysts. Hatching could be "rescued" by transfer of embryos grown in HTF+HSA to globulin-containing media and prevented by removal of globulins as late as the compacted morula stage (54 h).

CONCLUSIONS

SSS is superior to HSA alone for embryo culture. The stimulatory effects on mitosis and hatching may be mediated directly by globulins or by other components in the globulin-enriched fraction.

A serum-free medium for use in a cumulus cell co-culture system for bovine embryos derived from in vitro maturation and in vitro fertilization

The objective of this study was to develop a serum-free medium for the co-culture of bovine embryos that would yield a percentage of blastocysts equal to that obtained with fetal bovine serum (FBS)-supplemented medium. Cumulus cell-enclosed oocytes (CEO) matured and inseminated in vitro were cultured in a tissue culture medium (TCM)-199 or in a serum-free medium (bovine embryo culture medium; BECM) until 240 h post insemination. Replacement of 10% (v/v) FBS with either 3 mg crystallized bovine serum albumin (BSA)/ml or 3 mg fatty acid-free BSA/ml in TCM-199 had no effect (P > 0.14) on embryo development to the >or= 2-cell (51 to 60%), >or= 8-cell (24 to 33%), blastocyst (16 to 19%) and hatched-blastocyst (7 to 10%) stages at 48, 96, 192 and 240 h post insemination, respectively. Oocyte-enclosing cumulus cells in BSA-supplemented medium grew in clusters rather than in layers, as was noted in FBS-supplemented medium. When CEO were cultured in fatty acid-free BSA-supplemented media (TCM-199 and BECM), a significantly (P < 0.001) higher percentage of oocytes developed to blastocysts after culture with (22%) or without (18%) a cumulus cell monolayer than after denuding the oocytes (7%). Glucose in concentrations of 0 to 5.56 mM added for periods of 18 and 120 h post-insemination had neither a stimulatory nor a deleterious effect on preimplantation development. In conclusion, a serum-free medium supplemented with BSA can be successfully used in a cumulus cell co-culture system for bovine embryos.

Evaluation of synthetic serum substitute versus serum as protein supplementation for mouse and human embryo culture

PURPOSE

Our purpose was to determine the effect of Synthetic Serum Substitute (SSS) versus serum supplementation on fertilization rates and subsequent development of embryos from patients undergoing IVF.

PROCEDURE

Experiment I compared the effects of SSS to human serum on mouse embryo development. Two hundred one-cell B6D2F1 mouse embryos were cultured in 100-microliter droplets of human tubal fluid (HTF) containing either (1) no protein (control; n = 37), (2) 15% serum from women with tubal infertility (n = 44), (3) 15% serum from women with endometriosis (n = 49), (4) 15% fertile donor serum (n = 33), or (5) 15% SSS (n = 37). Experiment II compared the effects of SSS to human serum on the development of embryos from patients undergoing IVF. Thirty-three women were included in this study. A total of 371 oocytes was cultured in HTF containing either (1) maternal or donor serum (n = 140) or (2) 15% SSS (n = 231). Embryo development was evaluated 48 hr after fertilization.

RESULTS

In Experiment I, the rate of blastocyst development was evaluated at 48, 72, and 96 hr of culture. Sixty-four and nine-tenths percent of embryos cultured in SSS were morulae at 48 hr of culture (versus 5.4, 0, 8.2, and 6.1 in Groups 1, 2, 3, and 4, respectively). By 72 hr, 29.7% of these embryos had developed into blastocysts (versus 0, 0, 8.2, and 3.0, for Groups 1, 2, 3, and 4, respectively). This percentage increased to a total of 83.7 after 96 hr (versus 27.0, 20.4, 38.8, and 39.4 for Groups 1, 2, 3, and 4, respectively). Forty-three and two-tenths percent of the blastocysts cultured in SSS had hatched from their zonae by 96 hr. With the exception of Group 5, which had a rate of 9.1%, embryo hatching was not observed in any of the groups at the termination of culture (96 hr). In Experiment II there were no differences in cell stage or quality of human embryos cultured in SSS or serum, but fertilization rates tended to be better (P = 0.07) for oocytes inseminated in media containing SSS (70.0%, vs 55.0% for serum).

CONCLUSIONS

SSS appears to be a superior protein source for mouse embryo growth and is as good as serum from fertile donors in promoting in vitro human embryo development.

Serum is more effective than albumin in promoting human embryo development and implantation

OBJECTIVE

To compare the effects of serum with those of Albuminar-5 (Armour Pharmaceutical Co., Eastbourne, Sussex, United Kingdom) as medium supplements to Earl's balanced salt solution (EBSS) for IVF and subsequent embryo development.

DESIGN

A retrospective study. Gametes and embryos from 318 patients were cultured in the presence of serum (group 1). Gametes and embryos from 130 patients were cultured in the presence of Albuminar-5 (group 2). Embryos obtained from IVF were replaced into the uterus within 48 hours after insemination. Surplus bipronucleate embryos were cultured up to 14 days with either serum or Albuminar-5.

SETTING

Two tertiary referral fertility clinics; university teaching hospital.

PATIENTS

Four hundred forty-eight patients with a wide spectrum of causes of subfertility, ranging in age from 24 to 43 years.

MAIN OUTCOME MEASURES

Fertilization rate, pregnancy rate (PR), implantation rate, and surplus embryo development in vitro.

RESULTS

The PR for group 1 patients was higher than that of group 2 (27.0% versus 15.4%, respectively). Although fertilization rates were identical in the two groups, cumulative embryo scores and implantation rates were significantly higher in group 1. There was no difference between the groups in age distribution, types of ovarian stimulation, numbers of patients with day 1 or day 2 transfers, or luteal phase support. Of 31 embryos cultured with serum, 54.8% reached the fully expanded blastocyst stage and 25.8% hatched. Of 19 embryos cultured with Albuminar-5, only 5.3% reached the fully expanded blastocyst stage and none hatched.

CONCLUSIONS

The results suggest that, under certain conditions, serum supplementation yields better results than protein supplementation alone. The latter may be suitable only in conjunction with additional components.

Beneficial effects of taurine on mouse zygotes developing in protein-free culture medium

The objectives of this study were to determine if mouse zygotes from outbred mice can develop in simple culture medium in the absence of bovine serum albumin (BSA), and if taurine can be used as a medium supplement to improve development. Zygotes from 2 stocks of outbred mice (CD-1 and CF-1) were cultured in simple embryo culture medium (TE medium) lacking BSA and with or without taurine (24 mM), or in regular TE medium with BSA. The presence of BSA had little or no effect on development, but development to post-blastocyst endpoints was enhanced when CD-1 zygotes were cultured in medium containing taurine. In addition, when CD-1 blastocysts were transferred to pseudopregnant animals, embryos cultured in the presence of taurine developed into fetuses more often than those cultured in medium without taurine, and their weights were higher than those of embryos cultured in regular TE medium with BSA. These beneficial effects of taurine do not appear to be the nonspecific effects of a fixed nitrogen source, because the addition of glycine to BSA-free TE medium did not have similar beneficial effects. It was concluded that mouse zygotes from outbred mice do not require BSA for their preimplantation development in culture and that the presence of taurine in preimplantation culture medium is beneficial not only for preimplantation development of the zygotes, but also for their post-blastocyst development.

Screening of maternal sera using a mouse embryo culture assay is not predictive of human embryo development or IVF outcome

PURPOSE

Maternal serum is commonly added to media used for human IVF but can vary widely in its ability to support the development of human embryos in vitro. The objective of this study was to determine if the screening of maternal serum with a mouse one-cell embryo culture assay would be useful in predicting human embryo development and clinical outcome following IVF.

METHODS

Twenty-two individual serum samples from IVF patients were used as a supplement (7.5%) to Ham's F-10 media for culturing human embryos. All embryos were evaluated at the time of transfer for stage of development and embryo quality. Each serum sample was also tested for its ability to support mouse embryo development. One-cell embryos were recovered from superovulated female mice and cultured in serum-supplemented media. Mouse blastocyst development was assessed after 96 h of incubation.

RESULTS

No correlation was found between mouse blastocyst formation and human embryo development in media supplemented with maternal sera. Similarly, there was no association between the development of mouse blastocysts and clinical outcome following IVF. A subanalysis of patients whose sera tested poorly on the mouse assay again revealed no association between mouse and human embryo development.

CONCLUSION

Mouse embryo development in media containing human serum did not predict development of human embryos in vitro or clinical outcome following IVF. There would be little benefit to screening maternal sera using a mouse embryo culture system for determining its suitability for use in human IVF.

Effects of human serum supplementation on fertilization and development of mouse embryos

Serum is generally used as a protein supplement in culture media for human in vitro fertilization (IVF). To determine the effects of serum supplementation on the development of preimplantation embryos, one-cell and two-cell mouse embryos fertilized in vitro and in vivo were cultured in BWW medium supplemented with preovulatory patient serum (PS), human fetal cord serum (HCS), or bovine serum albumin (BSA). The rates of fertilization and development of embryos fertilized in vitro and in vivo were suppressed when the embryos were cultured with PS or HCS as compared with BSA. In the medium supplemented with HCS, growth of in vitro fertilized embryos was retarded at an earlier embryonic stage than was the case with embryos fertilized in vivo. These results suggest that the in vitro fertilized embryo culture model is more sensitive to culture conditions than is the in vivo fertilized embryo culture model. Incorporations of [3H]uridine and [3H]leucine were measured using embryos that developed to the blastocyst stage in a medium supplemented with HCS or BSA. Blastocysts cultured with HCS showed significantly higher incorporations of [3H]uridine and [3H]leucine than those cultured with BSA. While serum supplementation in culture media has adverse effects on embryo cleavage, it augments synthesis of RNA and protein.

Effects of oxygen concentration and oviductal epithelial tissue on the development of in vitro matured and fertilized bovine oocytes cultured in protein-free medium

Examination was made of the effects of oxygen concentration and supplementation of bovine oviductal epithelial tissue (BOET) on the development of bovine in vitro matured and fertilized (IVM/IVF) oocytes in a protein-free medium. The IVM/IVF embryos were cultured in protein-free tissue culture medium 199 supplemented with or without BOET under 5% CO2 in air (20% O2) or 5% CO2, 5% O2 and 90% N2 (5% O2). We found that blastocyst development without BOET at 5% O2 was the same as that with BOET at 20% O2 (30 vs 33%); BOET suppressed blastocyst development at 5% O2 (4%). Blastocysts cultured without BOET at 5% O2 developed into normal fetuses after transfer to recipient heifers. Examination was also made of oxygen pressure in the medium cultured with or without BOET at 20% O2 or 5% O2 by a blood gas analyzer. Oxygen pressure in the medium cultured with BOET at 20% O2 was lower than that without BOET (111.0+/-13.3 vs 149.2+/-1.3 mmHg). These results indicate that bovine IVM/IVF embryos can develop to the blastocyst stage in a protein-free medium without somatic cell support at low oxygen concentration (5%) and that the beneficial role of BOET for embryonic development may be to reduce oxygen concentration in the medium.

A serum-free, cell-free culture system for development of bovine one-cell embryos up to blastocyst stage with improved viability

With the aim of developing a serum-free, cell-free culture system for embryo development, in vitro-matured (IVM) and -fertilized (IVF) bovine oocytes were cultured in TCM 199 with the following supplements: 1) BSA alone (10 mg/ml); 2) BSA with ITS (5 mug/ml insulin, 5 mug/ml transferrin and 5 ng/ml selenium; BSAITS medium); 3) estrous cow serum alone (ECS; 10%); or 4) ECS with BOEC (bovine oviduct epithelial cells) (Experiment 1). In Experiment 2, embryos were cultured in BSAITS medium with or without feeding with fresh medium on Day 4 (day of insemination = Day 0). Embryos were evaluated on Day 2 for first cleavage, on Day 7 for morulae and blastocysts, and on Day 8 for blastocysts. Blastocysts from Experiment 1 were frozen in 10% glycerol in PBS, thawed and further cultured in ECS medium with BOEC for 48 h, and evaluated for formation of a distinct blastocoel, or expansion and hatching of blastocysts. In vivo-developed, Grade-1 and Grade-2, 7-d-old embryos served as control for the freezing, thawing and subsequent culture procedures. The percentage of first cleavage did not differ between the treatments (74 to 79% in Experiment 1 and 80 to 83% in Experiment 2). The percentage of blastocysts developed in BSAITS medium did not differ from that in ECS medium whether BOEC were present or not. However, medium with BSA alone had fewer blastocysts than any other culture system (P<0.05). Feeding embryos with fresh BSAITS medium on Day 4 did not lead to any further increase in the proportion of blastocysts. The culture systems had a significant effect on the post-thaw viability of blastocysts developed in them (P<0.001). Blastocysts developed in BSAITS medium had better (P<0.05) viability (14/38) than those from medium with ECS alone (1/27) or with ECS and BOEC (3/37). The post-thaw survival of control embryos was 80% (n=30). One of the three transfers of BSAITS-treated, frozen-thawed blastocysts resulted in a pregnancy. The results indicate that a serum-free, cell-free culture system can support the development of IVM-IVF bovine oocytes up to the blastocyst stage with better viability than a complex co-culture system.

Influence of culture medium and protein supplementation on in vitro oocyte maturation and fertilization in the domestic cat

Domestic cat oocytes were cultured either in Waymouth MB 753/1 Medium (WAY) or in Eagle's Minimum Essential Medium (MEM) containing FSH, LH and estradiol-17beta and supplememted with one of the following: 5% fetal calf serum (FCS); 4 mg/ml bovine serum albumin (BSA); or 3 mg/ml polyvinylalcohol (PVA, a non-protein control). The oocytes were evaluated for: nuclear maturation after 48 hours of culture (in vitro maturation, IVM); fertilization and cleavage 24 to 30 hours postinsemination (in vitro fertilization, IVF); and early embryo development 48 hours postinsemination. Maturation rates were similar (P>0.05) for WAY + BSA (29.4%), MEM + BSA (46.7%) and MEM + PVA (43.3%), but were different (P<0.05) from the other treatments (range, WAY + FCS, 9.6% to WAY + PVA, 14.9%). Fertilization and cleavage rates were also similar (P>0.05) for WAY + BSA (51.4%, 30.5%), MEM + BSA (45.8%, 40.1%) and MEM + PVA (56.1%, 37.4%) and were greater (P<0.05) than all other treatments. These IVM/IVF oocytes were capable of culturing beyond 2-cells, with the highest proportion of 4- and 8- cell embryos forming in WAY and MEM media in the presence of BSA or in MEM medium containing PVA. In the domestic cat IVM/IVF system: both the type of culture medium and protein supplement influence the proportion of oocytes reaching Metaphase II; the type of protein supplement has a more significant (P<0.05) impact than medium on fertilization, cleavage and early embryo development; and nuclear maturation and fertilization in vitro can proceed in this species in the absence of supplementary protein.

Effects of human sera and human serum albumin on mouse embryo culture

Human proteins normally used to supplement human in vitro fertilization-embryo transfer (IVF-ET) culture media were tested for their effects on mouse embryo development from the zygote stage. These proteins included follicular and luteal-phase maternal sera, fetal cord sera, and both human and bovine serum albumin. Our results revealed that both maternal and fetal cord sera did not permit mouse blastocyst formation. Furthermore, predialysis of the human maternal sera and removal of IgG by protein A column chromatography did not improve their support of mouse embryonic development to the blastocyst stage. Similar detrimental effects were observed with maternal sera from term-pregnant IVF-ET patients. Interestingly, these serum samples had supported the in vitro growth of the human zygotes which resulted in these patients' pregnancies. Only some batches of human serum albumin supported mouse blastocyst formation, whereas all sources of bovine serum albumin were effective in this regard. These results raise the question of the suitability of the mouse embryo culture system as a quality control for the testing of protein supplements for human IVF-ET.

Culture medium and protein supplementation influence in vitro fertilization and embryo development in the domestic cat

The influence of culture medium and protein supplements on in vitro fertilization (IVF) and morula-to-blastocyst development in culture was examined in the domestic cat. In Study I, follicular oocytes were fertilized and cultured in 1) modified Krebs Ringer bicarbonate (mKRB); 2) modified Tyrode's solution (TALP) without phosphate or glucose; or 3) Ham's F10. All media contained bovine serum albumin (BSA). Fertilization rates were similar (P greater than .05) among mKRB (75.0%), TALP (70.6%), and Ham's F10 (80.0%) treatments. Compared to TALP (77.8%), more (P less than .05) embryos in Ham's F10 (95.0%) developed to the morula stage; development of mKRB embryos (88.9%) was intermediate and not different (P greater than .05). Study II evaluated the effects of protein availability and type on IVF and embryo growth. Ham's F10 was supplemented with polyvinylalcohol (PVA, 2 mg/ml), BSA (4 mg/ml), fetal calf serum (FCS, 5%), or estrous cat serum (ECS, 5%) and used to fertilize and culture embryos. Fertilization was enhanced (P less than .05) using either FCS (84.0%) or ECS (85.2%) compared to PVA (67.3%). Oocytes exposed to BSA fertilized at a rate (76.1%) similar (P greater than .05) to other treatments. Embryos exposed to all four treatment groups (PVA, 82.8%; BSA, 82.8%; FCS, 92.9%; or ECS, 97.8%) were equally capable (P greater than .05) of becoming morulae. However, more FCS- or ECS-supplemented morulae continued to the early blastocyst stage (30.8%, 22.2%, respectively, P less than .05) than PVA- (10.3%) or BSA- (13.8%) exposed morulae. In the domestic cat IVF system, the type of medium and protein supplement used appears to have a greater impact on embryo development in vitro than on fertilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the hamster sperm motility assay to the mouse one-cell and two-cell embryo bioassays as quality control tests for in vitro fertilization

The hamster sperm motility assay, mouse one-cell embryo, and mouse two-cell embryo bioassays were used to test modified Tyrode's solution and modified Ham's F-10 (Gibco, Grand Island, NY) medium prepared in tap water versus ultrapure water. Factors influencing the ability of each assay to discriminate water quality were evaluated to characterize these assays for quality control use in the in vitro fertilization laboratory. The hamster sperm motility assay reproducibly detected differences in treatment without significant interanimal, interanalyst, or interassay variation. Interanalyst and interanimal variation significantly affected the ability to detect treatment differences using the mouse bioassays. Sample sizes needed to predict clinically significant treatment effects were calculated using varying assay conditions. Ham's F-10 medium can be tested with the hamster sperm motility assay.

Embryotoxicity of micropore filters used in liquid sterilization

Microfiltration is the usual method of sterilization of tissue culture media. The filtrates of eight commercial filters were tested for embryotoxicity using mouse embryo growth. Four of five disk filters tested showed embryo-toxicity in the first 5 ml of filtrate and the three larger-capacity filters showed embryotoxicity for up to the first 10 ml of filtrate. The ethylene oxide-sterilized filters appeared to give poorer results than the gamma-irradiated filters. The importance of discarding the initial filtrate or preflushing such filters before use is emphasized.

The incidence of human immunodeficiency virus (HIV) in fetal cord samples utilized as serum supplements for in vitro fertilization

Prior to initiating routine fetal cord serum (FCS) supplementation in our in vitro laboratory, the incidence of HIV in 306 random fetal cord samples obtained at the Labor and Delivery Unit of the Johns Hopkins Hospital from July 1985 to January 1988 was determined from a cross-sectional patient sample. Of 306 samples, 3 (0.98%) were positive for HIV, and confirmed by Western blot analysis, enzyme immunoassay (ELISA), a prevalence significantly higher than a national sample (0.012%). The use of FCS in this setting was determined to be an unacceptable risk to patients undergoing in vitro fertilization. The 90-day quarantine period for verification of HIV seronegativity applied to semen donors may not be applicable to FCS sampling. Patient risk may also increase with pooling of FCS samples prior to HIV testing.

Monozygous double inner cell masses in mouse blastocysts following fertilization in vitro and in vivo

The incidence of human identical twins after in vitro fertilization and embryo transfer (IVF-ET) is estimated to be higher than the commonly accepted incidence after conception in vivo. This paper reports that 8 mouse blastocysts which had double inner cell masses in 261 blastocysts (3.1%) were identified after fertilization in vitro and they developed into trophoblastic outgrowth formation with two inner cell masses. In contrast, only 3 monozygous double inner cell masses were observed in 526 blastocysts (0.6%) which were fertilized in vivo and cultured from the two-cell stage in vitro. It is therefore possible that fertilization in vitro predisposes to monozygous twinning.

Development of two-cell mouse embryos in protein-free and protein-supplemented media

Two-cell mouse embryos from CFW (Swiss-Webster) mice were cultured to the blastocyst stage in Ham's F10, Whittingham's T6, or human tubal fluid medium. Media were used without any protein supplements or were supplemented with human maternal serum, human fetal cord serum, or human serum albumin. Blastocysts were transferred to modified Eagle's basal medium supplemented with 10% fetal bovine serum for postblastocyst development. Blastocyst and postblastocyst development was depressed among embryos cultured during the preimplantation stage in protein-free Whittingham's T6 and human tubal fluid media compared with embryos cultured in protein-free Ham's F10 medium. This advantage of Ham's F10 disappeared when amino acids and vitamins were added to the other two media. Whittingham's T6 and human tubal fluid supplemented with human serum albumin, human maternal serum, or human fetal cord serum also supported excellent embryo development. When supplemented with protein, Ham's F10 was the poorest of the media in supporting embryo development. Although these results suggest that Ham's F10 is not the best medium for culture of mouse embryos, there is need for caution in extrapolating results from the mouse to the human.

Analysis of proteins secreted by mouse embryos developing in vivo and in vitro

Proteins secreted by mouse blastocysts developing in vitro were compared to these from blastocysts developing in utero to determine if a simple medium supporting blastocyst development also supports secreted protein expression. In-vivo embryos were collected on days 3, 4, or 5 of pregnancy and incubated in 35S-methionine to produce conditioned medium containing released, labeled proteins. Embryos for culture were collected on day 3 and after 48 or 72 h labeled conditioned medium was produced. Labeled proteins were separated by two-dimensional electrophoresis and compared using a digital image analysis system. Day 3 embryos did not release proteins in detectable amounts, although synthesis of intracellular proteins was substantial. Day-4 and -5 blastocysts released proteins in increasing amount and complexity, consistent with previous results. When day-3 embryos were cultured in medium containing 4 mg/ml BSA for 48 h, secreted protein patterns were similar but not identical to those of day-5 uterine blastocysts. Although most of the proteins produced by uterine blastocysts were secreted by cultured embryos, differences were found in the relative quantities of certain proteins. Neither crystallized BSA nor polyvinyl alcohol at 4 mg/ml supported development of protein secretion as well as the crude fraction-V BSA. Blastocysts restricted to the oviduct also exhibited quantitative differences in protein secretion patterns compared to uterine blastocysts. Thus, although blastocyst development and the expression of many secreted proteins are supported outside the uterus, the full pattern of secretion characteristic of the peri-implantation embryo may be dependent on specific uterine influences.

Bovine serum albumin (BSA) can replace patient serum as a protein source in an in vitro fertilization (IVF) program

Alternate protein sources have been suggested to replace the commonly used cord or patient serum for in vitro fertilization (IVF) procedures. During an 11-month period 127 patients treated for in vitro fertilization had either their serum (N = 71) or bovine serum albumin (BSA; N = 56) used as the protein source in the insemination and growth media. Ham's F-10 + 0.5% BSA was used for sperm swim-up and insemination media and 1% BSA was used for the growth media. Patient's serum was added to Ham's F-10 culture media at concentrations of 7.5 and 15% for insemination and growth, respectively. Embryo transfer was performed with Ham's F-10 containing 90% maternal serum in both groups. Fertilization rate of 259 oocytes inseminated in medium containing patient's serum did not differ when compared with 200 oocytes inseminated in medium containing BSA. Likewise, rates of abnormal fertilization, cleavage, and pregnancy were similar in both groups. In a second experiment, 148 normally fertilized oocytes were transferred after 24 hr in culture to growth media containing two different concentrations of BSA (0.5 or 1%). Cleavage rates for the two groups were similar and the percentage of embryos developed to greater than or equal to 4 cells did not differ significantly. We conclude that a single concentration of BSA can safely be used to supplement culture media in human IVF with several practical and economical benefits.

In vivo development of transferred mouse embryos conceived in vitro in simple and complex media

Ovulated mouse ova were fertilized in vitro and cultured to the four-cell stage in simple medium (modified Earle's balanced salts solution, EBSS) supplemented with bovine serum albumin (BSA) and in complex media (modified Ham's F-10 medium, Gibco, Grand Island, NY) with and without human cord serum supplementation. Fertilization and cleavage to the four-cell stage were the same for the three groups. Embryos in cohorts of six were transferred into oviducts of 14 to 16 pseudopregnant recipients per group. Pregnancy rates were higher for the EBSS/BSA and Ham's F-10 groups (36%) than for the Ham's F-10/cord serum group (19%). The percentage of embryos that developed into fetuses in the pregnant recipients was also higher for the Ham's F-10 group (47%) and the EBSS/BSA group (33%) than for the Ham's F-10/cord serum group (22%). The average fetal weights 17 days after transfer for the EBSS/BSA embryo group was 659 +/- 40 mg and for the Ham's F-10 group was 666 +/- 20 mg, higher (P less than 0.05 and P less than 0.003, respectively) than for the Ham's F-10/cord serum group, which was 522 +/- 30 mg. Although all developmental parameters were lower for the in vitro conceived embryos than for a control group of in vivo developed embryos transferred directly to pseudopregnant recipients, the cord serum culture conditions were the least supportive of normal embryo development.

The temporal effects of changes in in vitro fertilization culture media on the one-cell mouse embryo system

The one-cell mouse embryo system has previously been shown to be more sensitive than the two-cell system to mild changes in in vitro fertilization (IVF) culture media. To determine whether this greater sensitivity is related to the developmental stage or to the length of exposure, one-cell embryos were collected and cultured in control media (Ham's F-10, 282 mOsm/liter), in media of altered osmolality (260, 300, and 316 mOsm/liter), or in media containing Cidex diluted 1:100,000. The one-cell embryos were exposed to control or altered media in four patterns: control group--control medium for 96 hr; Group A--altered medium for the first 24 hr followed by control medium for 72 hr; Group B--control medium for the first 24 hr followed by altered medium for 72 hr; and Group C--control medium for the first 24 hr, altered medium for the next 24 hr, and control medium again for 48 hr. The percentage of embryos developing to blastocysts in Group A (exposed to adverse conditions only for the first 24 hr of culture) was significantly lower than in the control group under all conditions studied. In contrast, the percentage of blastocysts developing in Group B was significantly lower than in the control group only in medium of 315 mOsm/liter and was not different from that in controls under the other conditions studied. There was no difference between Group C and the control group. We conclude that the higher sensitivity of the one-cell system is an inherent property of the one-cell stage, as exposure of the embryo during this critical first 24-hr period proved to have the most profound consequences.

Mouse embryo culture as quality control for human in vitro fertilization: the one-cell versus the two-cell model

Female mice were superovulated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) and mated with male mice. One-cell (n = 429) and 2-cell (n = 450) embryos were collected 20 and 42 hours after hCG and cultured in Ham's F-10 medium (Gibco, Grand Island, NY) (282 mOsm/l, pH 7.4) and in media of altered osmolality (260, 300, 316 mOsm/l), altered pH (7.0, 7.8, 8.0) or various dilutions of Cidex (Surgikos, Arlington, TX) (1:1000, 1:10,000, 1:100,000). Stages of development were observed for 4 days. The development of embryos in the 1-cell system was significantly impaired under all studied conditions by the 4-cell stage of development. The 2-cell system failed to detect trace amounts of Cidex in the culture media and an increase in osmolality to 300 mOsm/l. Other changes in osmolality (260 mOsm/l) and pH (7.8) were detected by the 2-cell system only at the blastocyst stage. The authors conclude that the 1-cell system is more sensitive than the 2-cell system to mild changes in in vitro fertilization culture media.

Improved pronuclear mouse embryo development over an extended pH range in Ham's F-10 medium without protein

Pronuclear mouse embryos were cultured at four different pHs (7.17, 7.27, 7.37, and 7.50) in Ham's F-10 medium (Gibco, Grand Island, NY) alone and in Ham's F-10 medium supplemented with 10% human cord serum (v/v) to assess the effects of pH and serum on preimplantation embryo development. Media used in these experiments was stored both without (old protocol) or with triple gas equilibration (new protocol). Development was assessed by the percent of embryos developing to the 2-cell stage and on to the morula and blastocyst stages. Triple gas equilibration prior to media storage improved development to the morula and blastocyst stages. Development to the 2-cell and morula stages was not adversely affected by the presence of serum, but development to the blastocyst stage was significantly higher in Ham's F-10 medium without serum at all pHs tested. In conditions without serum, percent development at all stages examined was similar over the pH range of 7.17 to 7.37, with a significant decrease in development to the morula and blastocyst stage at pH 7.50. Embryos cultured in the presence of serum demonstrated a greater decrease in the percent development to blastocyst at both the low, 7.17 and 7.27, and high, 7.50, pHs, with an apparent pH optimum at 7.37. In summary, the complex media Ham's F-10 medium supports mouse embryo development without the need for serum. Serum inhibits pronuclear embryo development to the blastocyst stage. Mouse embryo culture in the absence of serum can tolerate a pH as low as 7.17 (8.4% CO2) without any detrimental effects.

The effect of serum fractions on single-cell mouse embryos in vitro

To examine the effect of various fractions of human fetal cord serum (HCS) on mouse embryos cultured in vitro, heat-inactivated HCS was separated by ultrafiltration into five distinct fractions: Fractions A, MW greater than 30,000; B, MW 30,000-10,000; C, MW 10,000-5,000; D, MW 5,000-1,000; and E, MW less than 1,000. Seven hundred twenty-eight single-cell embryos were cultured in TYH-280 medium supplemented with 8 mg/ml bovine serum albumin (BSA) and a 20% concentration of Fraction A, B, C, D, or E, whole HCS, or BSA alone. Embryos cultured with Fraction A or E or whole HCS demonstrated a significantly reduced growth rate (P less than 0.01), while embryos cultured with Fraction D demonstrated a significantly increased growth rate (P less than 0.01). Additionally, 649 single-cell embryos were cultured in medium which was supplemented with 8 mg BSA/ml and a 0, 1, 2, or 5% concentration of Fraction A or E. Fraction E displayed toxicity even at a 1% concentration (P less than 0.01), while Fraction A demonstrated growth inhibition at a 5% concentration (P less than 0.05) but increased the hatching rate at a 1% concentration (P less than 0.01). Finally, 635 single-cell embryos were cultured with four distinct fractions of HCS obtained from a Sephacryl S-200 column: Fractions I, MW 100,000; II, MW 70,000-100,000; III, MW 30,000-70,000; and IV, low molecular weight (less than 5,000).(ABSTRACT TRUNCATED AT 250 WORDS)