Evaluación de la capacidad de desarrollo in vitro de ovocitos bovinos provenientes de vacas con predominancia fenotípica Bos taurus y Bos indicus / Evaluation of in vitro development capacity of bovine oocytes obtained from predominantly Bos taurus and Bos indicus cows

El objetivo de este estudio fue evaluar la capacidad de desarrollo in vitro de ovocitos bovinos de vacas mestizas B. taurus y B. indicus. Los ovocitos fueron recuperados de ovarios de hembras bovinas provenientes de un matadero comercial. Para la obtención de los complejos cumulus-ovocitos (CCO) se realizó la técnica de slicing, seleccionando los ovocitos que tenían al menos una capa de células del cumulus y un citoplasma homogéneo. Los ovocitos seleccionados fueron madurados y fecundados in vitro (MIV-FIV). Se utilizó semen de un toro Brahman puro (B. indicus). Para la evaluación de la MIV y FIV todos los ovocitos se fijaron por al menos 24 h a 4°C en solución metanol-ácido acético (3:1) y teñidos con aceto-orceína al 1,1%. La tasa de maduración de ovocitos de vacas con predominancia fenotípica B. indicus fue del 66,17% mientras que las vacas con predominancia fenotípica B. taurus alcanzaron un 50,94% (P>0,05). En cuanto a la tasa de fecundación se obtuvo un 14,28 y 35,72% de ovocitos penetrados normalmente y anormales, respectivamente, para el grupo de ovocitos con predominancia fenotípica B. indicus. Mientras que para vacas con predominancia fenotípica B. taurus, un 10,22% correspondió a ovocitos penetrados normales y 19,31% de ovocitos penetrados anormales, sin encontrar diferencias estadísticamente significativas en ambos grupos. Los presentes resultados, tanto para la progresión meiótica como para las tasas de fecundación, indican que los ovocitos de vacas mestizas con predominancia fenotípica B. indicus son más competentes en las primeras etapas de desarrollo in vitro que los ovocitos de vacas mestizas con predominancia fenotípica B. taurus.

The aim of this study was to evaluate the in vitro development capacity of bovine oocytes from crossbred B. taurus and B. indicus cows. Oocytes from bovine cows were collected from commercial slaughterhouse. The cumulus-oocyte complex (COC) ovaries were obtained by Slicing technique, selecting those oocytes that had 2 to 3 layers of cumulus cells and homogeneous cytoplasm. After selection oocytes proceed with maturation (IVM) and fertilization in vitro (IVF). It used semen from a pure Brahman bull (B. indicus). For the assessment of IVM as for IVF oocytes were fixed for about 24 hours at 4°C in methanol-acetic acid (3:1) solution and stained with 1.1% aceto-orcein. The maturation rate of oocytes from cows with B. indicus phenotypic predominance was 66.17%, whereas cows with B. taurus phenotypic predominance 50.94% (P>0.05). Fertilization rate obtained in B. indicus phenotypic predominance group was 14.28% of oocytes normal penetrated and abnormal penetrated 35.72%, for cows with a phenotypic predominance B. taurus oocytes normal penetrated were 10.22% and 19.31% of abnormal oocytes penetrated. In conclusion, the present results indicate that oocytes from cows with phenotypic predominance B. indicus are more competent in the early stages of development in vitro than oocytes from cows with phenotypic predominance B. taurus.

Effect of beta-mercaptoethanol or epidermal growth factor supplementation on in vitro maturation of canine oocytes collected from dogs with different stages of the estrus cycle

Supplementation of beta-mercaptoethanol (beta-ME) in in vitro maturation (IVM) medium was shown to improve embryo development and quality in several species. Epidermal growth factor (EGF) was also shown to improve IVM of human oocyte and embryo development after in vitro fertilization (IVF). The effect of these two compounds were suggested to be mediated through the synthesis of glutathione (GSH) which is known to play an important role in protecting the cell or embryos from oxidative damage. Thus, it is suggested that supplementation of canine IVM medium with beta-ME or EGF may be of benefit due to its positive role in IVM of various mammalian oocytes and embryo development, including cattle, pigs, rodents and humans. This study investigates the effect of ovarian estrus stage on canine oocyte quality and supplementation of medium with beta-ME or EGF on IVM of canine oocytes. As results, a significantly higher percentage of oocytes progressed to metaphase II (MII) stage in 50 or 100 microM of beta-ME supplemented oocytes collected from the follicular stage. The maturation rate to metaphase I (MI) stage was also significantly higher in oocytes collected from follicular stage and cultured with 25 or 100 microM compared to other experimental groups. After IVM culture, oocytes recovered from dogs with the follicular stage and matured in TCM-199 supplemented with 20 ng/ml EGF yielded better oocyte maturation to MII phase compared to other groups. Taken together, supplementation of beta-ME (50 or 100 microM) or EGF (20 ng/ml) improved IVM of canine oocytes to MII stage.

In vitro maturation,fertilization and embryo transfer of immature oocytes derived from nature cycles / 重庆医科大学学报

Objective:To investigate the effect of in vitro maturation(IVM),fertilization and embryo transfer of immature oocytes derived from nature cycles in infertility couples.Methods:30 IVF/ICSI-ET cycles were involved in this study.Oocytes retrieval performed after follicle larger than 10 mm and before endogenesis Luteinizing hormone(LH) surge occurrence in nature cycle.Mature oocytes(Metaphase Ⅱ) were inseminated by standard in vitro fertilization(IVF) on the oocytes pick-up day.Immature oocytes(Metaphase I and germinal vesicle stage) were cultured for 24~48 hours and fertilized by intracytoplasmic sperm injection(ICSI) as soon as it developed to Metaphase Ⅱ stage.Embryo transfer was performed 72 h after fertilization.Results:2 of 30 IVM cycles brought no oocytes in this study.113 oocytes were obtained among other 28 oocyte retrieval cycles,74 of which were immature,29 were mature,and 10 were degenerated.60 of 74 immature oocytes developed to MⅡ after IVM(maturation rate 81.08%).6 cases of clinical pregnancy were obtained in the 20 embryo transfer cycles,five of which brought healthy babies(one came from immature oocyte and four came from mature oocyte) and one was abortive.Conclusion:IVM,fertilization and embryo transfer of immature oocytes derived from nature cycles is a feasible treatment for women with infertility.