Fertilization Archives - Revista Brasileira de Ginecologia e Obstetrícia
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2008;30(7):360-365
DOI 10.1590/S0100-72032008000700007
PURPOSE: to determine the relationship between the morphology of the first spindle pole of human oocytes and rates of fertilization, fragmentation and embryo quality in procedures of Intracytoplasmic Sperm Injection (ICSI). METHODS: retrospective study of 582 consecutive ICSI cycles, from July 2003 to July 2005. The morphology of the first spindle pole (SP) was assessed through the analysis of 3,177 oocytes in metaphase II, immediately before the ICSI procedure, always by the same observer. SP has been classified in the following categories: normal size intact, fragmented or augmented SP. Fertilization rate and fragmentation, and the number and rate of good quality embryos in each one of the three groups studied have been evaluated, 48 hours after ICSI (D2). Embryos with four cells, without fragmentation and with symmetric blastomeres in D2 were considered as of good quality. RESULTS: rates of fertilization, fragmentation and of good quality embryo formation, resulting from oocyte insemination, with augmented SP (20.7, 16.7 and 5% respectively) were significantly lower than the ones from intact and normal size SP (70.8, 62.5 and 19%, respectively) or from fragmented SP oocytes (69.7, 60.5 and 17.1%, respectively). CONCLUSIONS: it has been observed that the presence of augmented first spindle pole is related to worse rates of fertilization, fragmentation and bad quality embryo formation. Nevertheless, fragmentation in the first spindle pole of the oocyte does not seem to affect ICSI results.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2008;30(7):360-365
DOI 10.1590/S0100-72032008000700007
PURPOSE: to determine the relationship between the morphology of the first spindle pole of human oocytes and rates of fertilization, fragmentation and embryo quality in procedures of Intracytoplasmic Sperm Injection (ICSI). METHODS: retrospective study of 582 consecutive ICSI cycles, from July 2003 to July 2005. The morphology of the first spindle pole (SP) was assessed through the analysis of 3,177 oocytes in metaphase II, immediately before the ICSI procedure, always by the same observer. SP has been classified in the following categories: normal size intact, fragmented or augmented SP. Fertilization rate and fragmentation, and the number and rate of good quality embryos in each one of the three groups studied have been evaluated, 48 hours after ICSI (D2). Embryos with four cells, without fragmentation and with symmetric blastomeres in D2 were considered as of good quality. RESULTS: rates of fertilization, fragmentation and of good quality embryo formation, resulting from oocyte insemination, with augmented SP (20.7, 16.7 and 5% respectively) were significantly lower than the ones from intact and normal size SP (70.8, 62.5 and 19%, respectively) or from fragmented SP oocytes (69.7, 60.5 and 17.1%, respectively). CONCLUSIONS: it has been observed that the presence of augmented first spindle pole is related to worse rates of fertilization, fragmentation and bad quality embryo formation. Nevertheless, fragmentation in the first spindle pole of the oocyte does not seem to affect ICSI results.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(8):553-559
DOI 10.1590/S0100-72032003000800003
PURPOSE: to verify vitrification techniques using 6 M DMSO to cryopreserve in vitro matured bovine oocytes, and to assess the effects of the time of exposure to vitrification solutions (VS). METHODS: dilutions of VS were prepared from the stock VS (VS 100%) consisting of 6 M DMSO to give 25 and 65% DMSO solutions. Bovine oocytes were in vitro matured for 18-22 h. Matured oocytes were placed first into 25% VS, at room temperature for 5 min, then transferred to 65% VS, before being pipetted into the 100% VS in plastic straws. Three experimental groups were formed: in the first group, time of pipetting through 65% VS and loading the straw took up to 60 s, in the second group it did not exceed 30 s. For thawing, straws were held in air for 10 s and then in a water bath for 10 s. The contents of each straw were expelled in sucrose solution and held for 5 min. In the third experimental group, oocytes went through all VS, but were not vitrified. All retrieved oocytes were inseminated. For control, fresh, in vitro matured oocytes were inseminated. RESULTS: after vitrification, 69.1 and 59.8% of the oocytes were retrieved from the 30 s and 60 s groups, respectively, and 93 and 89% of these oocytes appeared morphologically normal 24 h after insemination, respectively. In the group of oocytes exposed without vitrification, 75.6% were retrieved and 84.7% were morphologically viable, 24 h after insemination. No fertilization was observed in the experimental groups. Among controls, 65.4% were fertilized. CONCLUSIONS: the vitrification technique using 6 M DMSO is not a feasible approach to cryopreserve in vitro matured bovine oocytes. Decreasing the time of exposure to VS did not overcome deleterious effects of the procedure on the fertilizability of oocytes. Improvements in the technique are needed to protect the zona pellucida and oolemma.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(8):553-559
DOI 10.1590/S0100-72032003000800003
PURPOSE: to verify vitrification techniques using 6 M DMSO to cryopreserve in vitro matured bovine oocytes, and to assess the effects of the time of exposure to vitrification solutions (VS). METHODS: dilutions of VS were prepared from the stock VS (VS 100%) consisting of 6 M DMSO to give 25 and 65% DMSO solutions. Bovine oocytes were in vitro matured for 18-22 h. Matured oocytes were placed first into 25% VS, at room temperature for 5 min, then transferred to 65% VS, before being pipetted into the 100% VS in plastic straws. Three experimental groups were formed: in the first group, time of pipetting through 65% VS and loading the straw took up to 60 s, in the second group it did not exceed 30 s. For thawing, straws were held in air for 10 s and then in a water bath for 10 s. The contents of each straw were expelled in sucrose solution and held for 5 min. In the third experimental group, oocytes went through all VS, but were not vitrified. All retrieved oocytes were inseminated. For control, fresh, in vitro matured oocytes were inseminated. RESULTS: after vitrification, 69.1 and 59.8% of the oocytes were retrieved from the 30 s and 60 s groups, respectively, and 93 and 89% of these oocytes appeared morphologically normal 24 h after insemination, respectively. In the group of oocytes exposed without vitrification, 75.6% were retrieved and 84.7% were morphologically viable, 24 h after insemination. No fertilization was observed in the experimental groups. Among controls, 65.4% were fertilized. CONCLUSIONS: the vitrification technique using 6 M DMSO is not a feasible approach to cryopreserve in vitro matured bovine oocytes. Decreasing the time of exposure to VS did not overcome deleterious effects of the procedure on the fertilizability of oocytes. Improvements in the technique are needed to protect the zona pellucida and oolemma.