Can Vero cell co-culture improve in-vitro maturation of bovine oocytes?
ABSTRACT This study was carried out to evaluate the effect of Vero cell co-culture on developmental competence of immature oocytes. Bovine cumulus-oocyte complexes (COC) were matured in presence or absence of Vero cells. Matured oocytes were inseminated and cultured for up to 9 days. Cleavage percentages were recorded on day 2 after insemination and embryos were evaluated on a daily basis. Expanding/expanded and hatching/hatched blastocysts were used for cell number assay. Results indicated a significantly greater cleavage percentage in oocytes matured in presence of Vero cells than control (86% versus 76%, P < or = 0.05). The percentages of advanced embryos appear to be greater on a daily basis in COC matured in presence of Vero cells compared with control. However, these differences were not significant. Blastocysts derived from COC matured in the presence of Vero cells had a significantly higher (P < or = 0.05) number of inner cell mass, trophectoderm and total cell number in expanding/expanded (65.25, 224.5 and 289.7 respectively) and hatching/hatched (67.75, 289.75 and 357.5) embryos in comparison to the control (42, 203.5, 245.5 and 51.3, 265, 316.3 respectively). Results confirm that co-culture of bovine COC during in-vitro maturation, enhances their ability for cleavage and for producing blastocysts with higher quality.
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ABSTRACT: Regulatory effect of GH on follicular growth and development in the cow is well documented. The aim of this study was to investigate the role of GH on in vitro bovine oocyte maturation. Therefore bovine cumulus oocyte complexes (COCs) were cultured in M199 without FCS and gonadotropins and in the presence of 10, 100, or 1,000 ng/ml bovine GH (NIH-GH-B18). The COCs were incubated at 39 degrees C in a humidified atmosphere with 5% CO2 in air and nuclear stage was assessed after 2, 4, 8, 16, 22, and 24 hr of incubation using DAPI staining. To assess the effect of GH on developmental capacity of the oocytes, COCs were incubated in the presence of GH for 22 hr, followed by IVF and in vitro embryo culture. Cultures without GH served as controls. For subsequent development, the embryos were cultured in M199 supplemented with 10% FCS on a monolayer of BRL cells. Embryos were scored morphologically and the efficiency of the culture system was evaluated as (1) the percentage of cleaved embryos 4 days after IVF, (2) the percentage of blastocysts on day 9 expressed on the basis of the number of oocytes at the onset of culture, and (3) the percentage of hatched blastocysts on day 11 expressed on the basis of the total number of blastocysts present at day 9. GH (100 and 1,000 ng/ml) significantly accelerated nuclear maturation (P < 0.001). At 4 and 8 h the percentage of oocytes in GV stage after GH treatment (54% and 19%) was significantly lower than the control (64% and 41%). Similarly at 16 and 22 h the percentage of oocytes in MII stage was significantly higher in the GH-treated group; (58% and 77%) and (46% and 62%) for GH and control respectively. The number of oocytes in MII beyond 22 hr of culture did not differ; 100 and 1,000 ng/ml GH induced significant cumulus expansion (P < 0.05), which was not observed in the absence of GH. Addition of 100 and 1,000 ng/ml GH during maturation significantly (P < 0.01) enhanced subsequent cleavage rate from (64% and 67%) in control to (75% and 81%) in GH-treated group; embryonic development in terms of day 9 blastocyst formation was also significantly increased in the presence of GH (29% and 34%) compared to the control (18% and 24%). The hatchability of the blastocysts was not influenced by GH. From the present data, it can be concluded that GH present during IVM has a beneficial effect on subsequent development.Molecular Reproduction and Development 12/1996; 45(3):372-7. · 2.81 Impact Factor
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ABSTRACT: The effectiveness of blastocyst culture and transfer in human in-vitro fertilization (IVF) was evaluated in a prospective randomized trial in patients having a moderate to good response to gonadotrophin stimulation. Embryos were transferred either on day 3 after culture to around the 8-cell stage in Ham's F-10 medium supplemented with fetal cord serum, or on day 5 after culture to the blastocyst stage in the sequential serum-free media G 1.2 and G 2.2. The pregnancy rates after transfer on day 3 or day 5 were equivalent, 66 and 71% respectively; however, significantly more embryos were transferred on day 3 (3.7) than on day 5 (2.2). The number of blastocysts transferred did not affect the implantation rate, and pregnancy rates when either two or three blastocysts were transferred were 68 and 87% respectively. The implantation rate of the blastocysts (50.5% fetal heart beat) was significantly higher compared to the cleavage stage embryos transferred on day 3 (30.1%). The percentage of blastocyst development was not affected by the number of 2-pronuclear embryos, or by maternal age. Irrespective of the number of blastocysts formed, pregnancy rates were similar. Furthermore, the pregnancy rate following blastocyst transfer in patients with 10 or more follicles at the time of human chorionic gonadotrophin administration was not affected by patient age. More than 60% of patients having blastocyst culture and transfer had supernumerary embryos for cryopreservation. The establishment of a pregnancy following thaw and transfer confirmed the viability of cryopreserved blastocysts cultured in the absence of serum or co-culture. The ability to transfer just two blastocysts while maintaining high pregnancy rates will therefore help to eliminate high order multiple gestations and improve the overall efficiency of human IVF.Human Reproduction 01/1999; 13(12):3434-40. · 4.67 Impact Factor
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ABSTRACT: We have investigated the effect of protein- and amino acid-free simple human tubal fluid (HTF) medium conditioned with bovine granulosa cells (BGC) or Vero cells on the development of early bovine embryos to the blastocyst stage. Serum-containing medium (SCM) and serum-free medium (CM) conditioned by BGC (BGC-SCM, BGC-CM) and by Vero cells (VC-SCM, VC-CM) were prepared. Early embryos (1-cell stage and 5- to 8-cell stage) were obtained by in vitro maturation and fertilization of oocytes from slaughtered cows. Embryos were randomly divided into 7 culture groups as follows: culture with BGC-SCM, BGC-CM, VC-SCM, or VC-CM; coculture with BGC or Vero cells; or culture with fresh HTF medium without serum. The proportion of 5- to 8-cell embryos developing to the blastocyst stage in BGC-CM (16%) and VC-CM (12%) was significantly lower (p < 0.05) than in BGC-SCM (41%) and in VC-SCM (29%) and after coculture with BGC (48%) and Vero cells (30%). Similarly, the percentages of 1-cell embryos developing to blastocyst in BGC-CM and VC-CM were significantly lower than in BGC-SCM and VC-SCM and after coculture. Cell numbers per blastocyst developed from 5- to 8-cell embryos in BGC-CM (96.8 cells) and in VC-CM (94.0 cells) were somewhat lower than those in BGC-SCM (128.5 cells) and VC-SCM (117.1 cells) and after coculture with BGC (124.2 cells) and Vero cells (115.3 cells). These results suggest that BGC and Vero cells cultured in a protein- and amino acid-free simple HTF medium synthesize and secrete factor(s) promoting blastocyst formation in vitro. Physiochemical analysis indicated that the embryotrophic substances in BGC-CM were distributed in two molecular size ranges, one between 10 kDa and 30 kDa and another greater than 30 kDa.Biology of Reproduction 04/1996; 54(4):930-6. · 4.03 Impact Factor