Utilización de compuestos tiol en la producción in vitro de embriones a partir de ovocitos de cabras prepúberes

Con el fin de mejorar la producción in vitro de embriones (PIVE) desde ovocitos de cabra perpúber, fueron diseñados tres estudios en esta investigación. El objetivo del primer estudio fue determinar en ovocitos seleccionados mediante el test azul de cresol brillante (BCB), el efecto de la adición de gutatión (GSH) solo o en combinación con glucosa al medio de cultivo in vitro (CIV), sobre el desarrollo embrionario de ovocitos de cabra perpúber. Los ovocitos fueron expuestos al test de BCB y fueron clasificados como: ovocitos con citoplasma azul (BCB+) y ovocitos sin el citoplasma azul (BCB-). Los ovocitos BCB+ mostraron mayor porcentaje de maduración nuclear que los ovocitos BCB- y grupo control (82.6%, 55.7% y 74.7% respectivamente). El porcentaje de ovocitos poliespérmicos fue mayor en ovocitos BCB- que en los BCB+. La suplementación del medio de cultivo (CIV) con 1 mM de GSH, no afectó el desarrollo embrionario, pero el porcentaje de embriones totales desarrollados después del cultivo fue mayor en ovocitos BCB+ que en los BCB-, independientemente de la suplementación con GSH. La adición de glucosa, sola o con GSH no afectó el desarrollo embrionario. La finalidad del segundo estudio era evaluar el efecto de agregar diferentes concentraciones de cisteamina (100μM, 200μM o 400μM) al medio de MIV y al medio de CIV (50 μM o 100 μM) sobre el desarrollo embrionario de ovocitos de cabra perpúber seleccionados por el test BCB. La adición de 400 μM de cisteamina al medio MIV mejoró la fecundación normal y desarrollo embrionario de ovocitos BCB- a los mismos niveles de los ovocitos BCB+. Las proporciones de mórulas mas blastocistos desarrollados no fueron afectados por los tratamientos. Finalmente, fue estudiado el efecto de la adición de cisteamina (400 μM) para el medio de MIV, glutatión (1mM) al medio FIV e ionomicina al medio de capacitación espermática. Este tratamiento mejoró la fecundación normal, cigotos con pronúcleos masculinos y el desarrollo embrionario de ovocitos de cabra prepuber, sin embargo no mejoró el desarrollo de blastocistos.With the aim of trying to improve in vitro embryo production (IVEP) from prepubertal goat oocytes, three studies were designed in this investigation. The objetive of first study was to assess, in oocytes selected by the brillant cresyl blue (BCB) test, the effect of the addition to in vitro culture (IVC) medium of either glutathione (GSH) alone or GSH in combination with glucose on the embryo development. Oocytes were exposed to BCB and were classified as: oocytes with a blue cytoplasm (BCB+) and oocytes without blue cytoplasm (BCB-). BCB+ oocytes showed higher percentage of nuclear maturation than the BCB- and control group (82.6%, 55.7% and 74.7%, respectively). The percentage of polyspermic oocytes was higher in BCB- than BCB+ oocytes. Supplementation of in vitro culture (IVC) medium with 1mM de GSH did not affect embryo development, but the porcentage of total embryos developed after culture was higher in BCB+ oocytes than in BCB- oocytes independently of the GSH supplementation. The addition of glucose, alone or with GSH, did not affect embryo development. The aim of the second study was to evaluate the effect of adding different concentrations (100μM, 200μM and 400 μM) of cyteamine to the IVM medium and to the in vitro embryo culture (IVC) medium (50 μM or 100 μM) on the embryo development of prepubertal goat oocytes BCB-selected. The addition of 400 μM cysteamine to the IVM improved normal fertilisation and embryo development of BCB- oocytes at the same rates as those obtained from BCB+ oocytes. The proportions of morulae plus blastocyst development were not affects by the treatments. Finally, was studied the effect of adding cysteamine (400 μM) to IVM medium, glutathione (1mM) to IVF medium and ionomycin to the sperm capacitation medium. This treatment improved normal fertilisation, zygotes with male pronucleus and embryo development of prepubertal goat oocytes, however did not improve blastocyst development

Effect of Roscovitine on nuclear maturation, MPF and MAP kinase activity and embryo development of prepubertal goat oocytes

The low number of embryos obtained from IVM-IVF-IVC of prepubertal goat oocytes could be due to an incomplete cytoplasmic maturation. Roscovitine (ROS) inhibits MPF and MAP kinase activity and maintains the oocyte at Germinal Vesicle (GV) stage. The aim of this study was to determine if meiotic activity is arrested in prepubertal goat oocytes cultured with 0, 12.5, 25, 50 and 100 m M of ROS for 24 h. A group of oocytes from adult goats was cultured with 25 m M of ROS to compare the effect of ROS on prepubertal and adult goat oocytes. A sample of oocytes was stained to evaluate the nuclear stage at oocyte collection time and after ROS incubation. IVM-oocytes not exposed to ROS formed the control group. Prepubertal goat IVM-oocytes were inseminated and cultured for 8 days. The percentage of oocytes at GV stage, after exposition to ROS was significantly higher in adult goat oocytes (64.5%) than in prepubertal goat oocytes. No differences were found among 25, 50 and 100 m M ROS concentrations (29, 23 and 26%, oocytes at GV stage, respectively). After 8 days of culture, no differences in total embryos were observed between control oocytes and oocytes treated with 12.5 and 25 m M (45.2, 36.1 and 39.4%, respectively), however the percentage of lastocysts was higher in the control group. Western blot for the MAPK and p34 cdc2 showed that both enzymes were active in prepubertal goat oocytes after 24 h of ROS exposition. In conclusion, a low percentage of prepubertal goat oocytes reached GV stage after ROS incubation; possibly because most of them had reinitiated the meiosis inside the follicle. ROS did not affect fertilization or total embryos but ROS showed a negative effect on blastocyst development

Cysteamine, glutathione and ionomycin treatments improve IVF of prepubertal goat oocytes

The aim of this study was to improve in vitro embryo development of prepubertal goat oocytes by T1 studying the effect of adding cysteamine to in vitro maturation medium, glutathione (GSH) to in vitro fertilization medium and ionomycin to the sperm capacitation medium. In experiment 1, we analysed the effect of 1mM GSH added to fertilization medium of oocytes matured with 400 μ M cysteamine. The control group were oocytes without cysteamine and GSH. In experiment 2, oocytes matured and fertilized in the presence of 400 μ M cysteamine and 1 mM GSH, respectively, were inseminated with spermatozoa treated with ionomycin or heparin. In experiment 1, the percentages of total and normal fertilized oocytes were significantly higher for oocytes supplemented with cysteamine and GSH (40.26% and 30.20%, respectively) than for oocytes from the control group (16.66%, and 10.61%, respectively). The percentage of total embryos obtained after 7 days of culture was significantly higher in the group supplemented with cysteamine and GSH (30.62%) than in the control group (8.09%). In experiment 2, percentages of total and normal fertilized oocytes were significantly higher for the group of spermatozoa capacitated with ionomycin (52.21% and 37.17%, respectively) than with heparin (38.62% and 28.35%, respectively). After 7 days of culture, total embryo rate was significantly higher in the group of sperm capacitated with ionomycin (44.91%) than with heparin (38.69%). However, the percentage of embryos developed to the blastocyst stage was not affected by any of the treatments studied

Cysteamine, glutathione and ionomycin treatments improve IVF of prepubertal goat oocytes

The aim of this study was to improve in vitro embryo development of prepubertal goat oocytes by T1 studying the effect of adding cysteamine to in vitro maturation medium, glutathione (GSH) to in vitro fertilization medium and ionomycin to the sperm capacitation medium. In experiment 1, we analysed the effect of 1mM GSH added to fertilization medium of oocytes matured with 400 μ M cysteamine. The control group were oocytes without cysteamine and GSH. In experiment 2, oocytes matured and fertilized in the presence of 400 μ M cysteamine and 1 mM GSH, respectively, were inseminated with spermatozoa treated with ionomycin or heparin. In experiment 1, the percentages of total and normal fertilized oocytes were significantly higher for oocytes supplemented with cysteamine and GSH (40.26% and 30.20%, respectively) than for oocytes from the control group (16.66%, and 10.61%, respectively). The percentage of total embryos obtained after 7 days of culture was significantly higher in the group supplemented with cysteamine and GSH (30.62%) than in the control group (8.09%). In experiment 2, percentages of total and normal fertilized oocytes were significantly higher for the group of spermatozoa capacitated with ionomycin (52.21% and 37.17%, respectively) than with heparin (38.62% and 28.35%, respectively). After 7 days of culture, total embryo rate was significantly higher in the group of sperm capacitated with ionomycin (44.91%) than with heparin (38.69%). However, the percentage of embryos developed to the blastocyst stage was not affected by any of the treatments studied

Effect of Roscovitine on nuclear maturation, MPF and MAP kinase activity and embryo development of prepubertal goat oocytes

The low number of embryos obtained from IVM-IVF-IVC of prepubertal goat oocytes could be due to an incomplete cytoplasmic maturation. Roscovitine (ROS) inhibits MPF and MAP kinase activity and maintains the oocyte at Germinal Vesicle (GV) stage. The aim of this study was to determine if meiotic activity is arrested in prepubertal goat oocytes cultured with 0, 12.5, 25, 50 and 100 m M of ROS for 24 h. A group of oocytes from adult goats was cultured with 25 m M of ROS to compare the effect of ROS on prepubertal and adult goat oocytes. A sample of oocytes was stained to evaluate the nuclear stage at oocyte collection time and after ROS incubation. IVM-oocytes not exposed to ROS formed the control group. Prepubertal goat IVM-oocytes were inseminated and cultured for 8 days. The percentage of oocytes at GV stage, after exposition to ROS was significantly higher in adult goat oocytes (64.5%) than in prepubertal goat oocytes. No differences were found among 25, 50 and 100 m M ROS concentrations (29, 23 and 26%, oocytes at GV stage, respectively). After 8 days of culture, no differences in total embryos were observed between control oocytes and oocytes treated with 12.5 and 25 m M (45.2, 36.1 and 39.4%, respectively), however the percentage of lastocysts was higher in the control group. Western blot for the MAPK and p34 cdc2 showed that both enzymes were active in prepubertal goat oocytes after 24 h of ROS exposition. In conclusion, a low percentage of prepubertal goat oocytes reached GV stage after ROS incubation; possibly because most of them had reinitiated the meiosis inside the follicle. ROS did not affect fertilization or total embryos but ROS showed a negative effect on blastocyst development