Effect of Different Manganese Concentrations during in vitro Maturation of Bovine Oocytes on DNA Integrity of Cumulus Cells and Subsequent Embryo Development

Manganese (Mn) is a trace element present in forages and cereals, and its concentration depends on soil status. Manganese deficiency in cattle, goats and ewes not only impairs oestrous cycle but reduces calf birth weight. The achievement of the first oestrus is delayed, and more attempts are necessary to obtain a successful conception. This study was conducted to investigate the effect of the availability of supplemental Mn during IVM on DNA damage of cumulus cells and total glutathione (GSH) content in oocytes and cumulus cells. The effect of supplementary Mn during IVM on subsequent embryo development was also studied. The results reported here indicate (i) DNA damage in cumulus cells decreased with 0, 2, 5 and 6 ng/ml Mn supplementation during IVM (p < 0.05). (ii) Intracellular GSHGSSG content increased (p < 0.01) with different Mn concentrations in oocytes and cumulus cells. Also, cumulus cell number per cumulus oocyte-complexes (COC) did not differ either before or after IVM. (iii) Addition of Mn to maturation medium resulted in similar cleavage rates (p > 0.05) at 0, 2, 5 and 6 ng/ml Mn. However, subsequent embryo development to blastocyst stage was significantly higher (p < 0.01) in oocytes matured with 5 and 6 ng/ml Mn. (iv) There was also an increase (p < 0.05) in mean cell number per blastocyst obtained from oocytes matured with 5 and 6 ng/ml respect to zero Mn (IVM alone) and 2 ng/ml Mn. This study provides evidence that optimal embryo development to the blastocyst stage was partially dependent on the presence of Mn during IVM. Moreover, the availability of Mn during oocyte maturation ensures ‘normal’ intracellular GSH content in COCs and protects DNA integrity of cumulus cells.

Fil: Anchordoquy, Juan Patricio. Universidad Nacional de la Plata. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Laboratorio de Nutricion Mineral y Fisiologia Reproductiva; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Genética Veterinaria;

Fil: Anchordoquy, Juan Mateo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Genética Veterinaria; Universidad Nacional de la Plata. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Laboratorio de Nutricion Mineral y Fisiologia Reproductiva; Argentina;

Fil: Sirini, Matias Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Genética Veterinaria; Universidad Nacional de la Plata. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Laboratorio de Nutricion Mineral y Fisiologia Reproductiva; Argentina;

Fil: Mattioli, Guillermo Alberto. Universidad Nacional de la Plata. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Laboratorio de Nutricion Mineral y Fisiologia Reproductiva; Argentina;

Fil: Picco, Sebastian Julio. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - la Plata. Instituto de Genetica Veterinaria Ing Fernando Noel Dulout; Universidad Nacional de la Plata. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Laboratorio de Nutricion Mineral y Fisiologia Reproductiva; Argentina;

Fil: Furnus, Cecilia Cristina. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - la Plata. Instituto de Genetica Veterinaria Ing Fernando Noel Dulout; Universidad Nacional de la Plata. Facultad de Cs.medicas. Departamento de Ciencias Morfologicas. Catedra de Citologia y Embriologia A; Argentina;