Translocation of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro.

The distribution of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro was revealed by using MitoTracker Green staining and confocal laser scanning microscopy. The regulation of mitochondrial translocation by microfilaments and microtubules was also studied. In oocytes collected from small follicles, strong staining of active mitochondria was observed in the cell cortex. Accumulation of active mitochondria in the peripheral cytoplasm and around the germinal vesicles was characteristic of fully grown oocytes collected from large follicles. Mitochondria accumulated in the perinuclear area during meiotic progression from germinal vesicle breakdown (GVBD) to anaphase I. Larger mitochondrial foci were formed and moved to the inner cytoplasm in mature oocytes. Compared with the oocytes matured in vivo, in which large mitochondrial foci were distributed throughout the cytoplasm, mitochondria were not observed in the central cytoplasm in most of the oocytes matured in vitro. Strong staining of mitochondria was observed in the first polar bodies in metaphase II oocytes. In fertilized eggs, active mitochondria aggregated in the pronuclear region. Perinuclear clustering and a cortical ring were the most marked features of early cleavage. Active mitochondria were distributed in both inner cell mass cells and trophectoderm cells of the blastocysts. Disassembly of microtubules with nocodazole inhibited both mitochondrial aggregations to the germinal vesicle area and their inward movement to the inner cytoplasm during oocyte maturation, as well as the translocation of mitochondria to the peri-pronuclear region during fertilization, whereas disruption of microfilaments by cytochalasin B had no effects. These data indicate that: (i) oocyte maturation, fertilization and early embryo development in pigs are associated with changes in active mitochondrial distribution; (ii) mitochondrial translocation is mediated by microtubules, but not by microfilaments; and (iii) in vitro maturation conditions may cause incomplete movement of mitochondria to the inner cytoplasm and thus affect cytoplasmic maturation.

[1]  R. Prather,et al.  Nuclear control of early embryonic development in domestic pigs. , 2020, Journal of reproduction and fertility. Supplement.

[2]  R. Prather,et al.  Dynamic Events Are Differently Mediated by Microfilaments, Microtubules, and Mitogen-Activated Protein Kinase During Porcine Oocyte Maturation and Fertilization In Vitro1 , 2001, Biology of reproduction.

[3]  J. van Blerkom,et al.  Differential mitochondrial distribution in human pronuclear embryos leads to disproportionate inheritance between blastomeres: relationship to microtubular organization, ATP content and competence. , 2000, Human reproduction.

[4]  D M Porterfield,et al.  Oxidative Phosphorylation-Dependent and -Independent Oxygen Consumption by Individual Preimplantation Mouse Embryos1 , 2000, Biology of reproduction.

[5]  B. N. Day,et al.  Pronuclear location before the first cell division determines ploidy of polyspermic pig embryos. , 1999, Biology of reproduction.

[6]  M. Clayton,et al.  Glucose and phosphate toxicity in hamster preimplantation embryos involves disruption of cellular organization, including distribution of active mitochondria , 1997, Molecular reproduction and development.

[7]  B. Bavister,et al.  Translocation of active mitochondria during hamster preimplantation embryo development studied by confocal laser scanning microscopy , 1996, Developmental dynamics : an official publication of the American Association of Anatomists.

[8]  J. van Blerkom,et al.  ATP content of human oocytes and developmental potential and outcome after in-vitro fertilization and embryo transfer. , 1995, Human reproduction.

[9]  S. M. Downs,et al.  The participation of energy substrates in the control of meiotic maturation in murine oocytes. , 1994, Developmental biology.

[10]  J. van Blerkom,et al.  Cellular and developmental biological aspects of bovine meiotic maturation, fertilization, and preimplantation embryogenesis in vitro. , 1990, Journal of electron microscopy technique.

[11]  P. Hyttel,et al.  Ultrastructure of in-vitro oocyte maturation in cattle. , 1986, Journal of reproduction and fertility.

[12]  J. van Blerkom,et al.  Mitochondrial reorganization during resumption of arrested meiosis in the mouse oocyte. , 1984, The American journal of anatomy.

[13]  B. N. Day,et al.  Practical considerations for the in vitro production of pig embryos. , 1998, Theriogenology.

[14]  Sun Qing-yua.  Chronological and Morphological Progression of Nucleus during Mouse Oocyte Maturation and Fertilization in vitro , 1996 .

[15]  J. van Blerkom,et al.  Microtubule mediation of cytoplasmic and nuclear maturation during the early stages of resumed meiosis in cultured mouse oocytes. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[16]  J. Eppig.  The relationship between cumulus cell-oocyte coupling, oocyte meiotic maturation, and cumulus expansion. , 1982, Developmental biology.

[17]  L. Zamboni,et al.  Electron microscopic studies on rabbit ova , 1966 .