Fertilization and early embryology: Intracytoplasmic sperm injection for Rhesus monkey fertilization results in unusual chromatin, cytoskeletal, and membrane events, but eventually leads to pronuclear development and sperm aster assembly
Source: Human Reproduction, Volume 11, Number 8, August 1996 , pp. 1703-1712(10)
Publisher: Oxford University Press
Abstract:The disassembly and reorganization of sperm-derived structures are landmarks for the onset of embryonic development. Since complete information on these events is not yet available, we examined the disassembly of the sperm axoneme, the formation of the sperm aster, and the decondensation and development of the male and female pronuclel in inseminated Rhesus monkey oocytes conceived by in-vitro fertilization (IVF) or by intracytoplassnic sperm injection. During IVF, the spermatozoa lose their acrosomes after contacting the zona pellucida, and the plasma membrane and nuclear envelope disappear after fusion with the oolemma. Subsequently, a sperm aster of microtubules forms around the proximal centriole, which is bound to the sperm connecting piece. This process is then followed by the formation of both pronuclei. The single sperm centriole later duplicates and the bipolar mitotic apparatus is observed. Following sperm injection, the spermatozoa have both an intact plasma membrane and acrosome. Although the microtubules form the sperm aster in a fashion identical to that seen during IVF, the presence of an intact acrosome appears to be associated with a heterogeneity in the decondensation of sperm chromatin. While this may indicate an abnormal pattern of chromatin decondensation during the formation of the male pro-nucleus following sperm injection, the male pronucleus eventually fully decondenses, as during 1W. Sperm mito chondria are displaced as the sperm centriole is exposed. Annulate lamellae and a previously undescribed organelle which seems to contain annulate lamellae precursors, as well as maternal mitochondria, are found in association with the developing pronuclear envelopes. This information increases understanding of fertilization in primates, and may also be of significance for use in assisted human reproduction as well as in the preservation of endangered mammalian species. In addition, these results demonstrate the similarities between fertilization in Rhesus monkeys and humans, providing additional evidence for the use of this non-human primate as a model system in which to investigate the cellular and molecular biological basis of human reproduction.
Document Type: Research Article
Publication date: 1996-08-01
- Human Reproduction features full-length, peer-reviewed papers reporting original research, clinical case histories, as well as opinions and debates on topical issues. Papers published cover the scientific and medical aspects of reproductive physiology and pathology, endocrinology, andrology, gonad function, gametogenesis, fertilization, embryo development, implantation, pregnancy, genetics, genetic diagnosis, oncology, infectious disease, surgery, contraception, infertility treatment, psychology, ethics and social issues. The highest scientific and editorial standard is maintained throughout the journal along with a rapid rate of publication.