Centrosomal Function Assessment in Human Sperm Using Heterologous ICSI with Rabbit Eggs: A New Male Factor Infertility Assay

Yukihiro Terada, Sou Ichi Nakamura, Calvin Simerly, Laura Hewitson, Takashi Murakami, Nobuo Yaegashi, Kunihiro Okamura, Gerald Schatten

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


Sperm centrosomal function was assessed by immunocytochemical analysis after the injection of human sperm into mature rabbit eggs. Three hours after intracytoplasmic sperm injection (ICSI), an astral microtubule array from the base of the human sperm was observed in the rabbit eggs. This sperm aster expanded in the egg cytoplasm, concommitant with pronuclear formation, and a dense microtubule array was organized at the time of pronuclear centration. Using fertile donor sperm, the sperm aster formation rate at 3 hr after ICSI was 35.0 ± 1.5%. Using sperm from infertile patients, the average aster formation rate was lower (25.4 ± 14.8%, P < 0.05). Among infertile cases, there was no correlation between sperm aster formation rates and conventional parameters of semen analysis. However, the sperm aster formation rate correlated with the embryonic cleavage rate following human in vitro fertilization (IVF). These data suggest that this assay reflects sperm function during embryonic development after sperm entry and that reproductive success during the first cell cycle requires a functional sperm centrosome. Furthermore, sperm centrosomal function cannot be predicted from conventional parameters of semen analysis. We propose that insufficient centrosomal function could be the cause of certain cases of idiopathic infertility. These assays may lead to the discovery of new types of infertility, which have previously been treated as "unexplained infertility," and may also lead to the treatment of infertility incurable even by ICSI. Consequently, an accurate and relevant assay to help assure couples of the success of fertilization is warranted, perhaps prior to ICSI therapy.

Original languageEnglish
Pages (from-to)360-365
Number of pages6
JournalMolecular reproduction and development
Issue number3
Publication statusPublished - 2004 Mar 1


  • ICSI
  • Male infertility
  • Rabbit egg
  • Sperm aster
  • Sperm centrosome

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology
  • Cell Biology


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