Sperm chromatin remodeling after intracytoplasmic sperm injection differs from that of in vitro fertilization.

Full Abstract

Intracytoplasmic sperm injection (ICSI) is a popular method used in assisted conception, and live offspring have been born from a variety of species, including humans. In ICSI, sperm chromatin is introduced into the oocyte together with the acrosome, a structure that does not enter the oocyte during normal fertilization. We compared sperm chromatin remodeling, the potential of embryos to develop in vitro, and DNA synthesis in mouse embryos obtained from in vitro fertilization (IVF) and ICSI. We also tested whether sperm pretreatment prior to ICSI (i.e., capacitation, acrosome reaction, membrane removal, and reduction of disulfide bonds in protamines) facilitates chromatin remodeling and affects embryo development. Sperm chromatin was examined on air-dried, Giemsa-stained preparations at 30-min intervals for up to 4.5 h postfertilization. In all experimental groups, the oocytes underwent activation and formed pronuclei with similar rates. However, the dynamics of sperm chromatin remodeling in ICSI and IVF embryos varied. In ICSI, chromatin remodeling was more asynchronous than in IVF. Sperm capacitation prior to injection enhanced remodeling asynchrony and resulted in delayed pronuclei formation and DNA synthesis. The removal of the acrosome prior to injection with calcium ionophore A23187 but not with detergent Triton X-100 allowed more synchronous chromatin remodeling, timely DNA synthesis, and good embryo development. Our data have significance for the refinement of the molecular and biologic mechanisms associated with ICSI for current and future applications.

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Author information

Author/s: Ajduk, Anna (A); Yamauchi, Yasuhiro (Y); Ward, Monika A (MA);

Affiliation: Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96822, USA.

Grants: R21 HD048845 (Agency:NICHD NIH HHS)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural

Journal: Biology of reproduction (Biol Reprod), published in United States. (Language: eng)

Reference: 2006-Sep; vol 75 (issue 3) : pp 442-51

Dates: Created 2006/08/24; Completed 2007/11/13; Revised 2007/12/03;

PMID: 16775225, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Acrosome Reaction - physiology
Animals
Calcimycin - pharmacology
Chromatin - physiology
Coloring Agents
DNA Replication - physiology
Detergents - pharmacology
Embryonic Development
Female
Fertilization in Vitro

Ionophores - pharmacology
Male
Mice
Mice, Inbred C57BL
Mice, Inbred DBA
Octoxynol - pharmacology
Oocytes - metabolism
Pregnancy
Sperm Injections, Intracytoplasmic
Spermatozoa - physiology

Associated Chemicals: Chromatin (0) ; Coloring Agents (0) ; Detergents (0) ; Ionophores (0) ; Calcimycin (52665-69-7) ; Octoxynol (9002-93-1)

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