Document Detail

Functional assessment of centrosomes of spermatozoa and spermatids microinjected into rabbit oocytes.
MedLine Citation:
PMID:  18646048     Owner:  NLM     Status:  MEDLINE    
Although intracytoplasmic sperm injection (ICSI) is a widely used assisted reproductive technique, the fertilization rates and pregnancy rates of immature spermatids especially in round spermatid injection (ROSI) remain very low. During mammalian fertilization, the sperm typically introduces its own centrosome which then acts as a microtubule organizing center (MTOC) and is essential for the male and female genome union. In order to evaluate the function of immature germ cell centrosomes, we used the rabbit gamete model because rabbit fertilization follows paternal pattern of centrosome inheritance. First, rabbit spermatids and spermatozoa were injected into oocytes using a piezo-micromanipulator. Next, the centrosomal function to form a sperm aster was determined. Furthermore, two functional centrosome proteins (gamma-tubulin and centrin) of the rabbit spermatogenic cells were examined. Our results show that the oocyte activation rates by spermatozoa, elongated spermatids, and round spermatids were 86% (30/35), 30% (11/36), and 5% (1/22), respectively. Sperm aster formation rates after spermatozoa, elongated spermatids, and round spermatids injections were 47% (14/30), 27% (3/11), and 0% (0/1), respectively. The aster formation rate of the injected elongating/elongated spermatids was significantly lower than that of the mature spermatozoa (P = 0.0242). Moreover, sperm asters were not observed in round spermatid injection even after artificial activation. These data suggest that poor centrosomal function, as measured by diminished aster formation rates, is related to the poor fertilization rates when immature spermatogenic cells are injected.
Masahito Tachibana; Yukihiro Terada; Narumi Ogonuki; Tomohisa Ugajin; Atsuo Ogura; Takashi Murakami; Nobuo Yaegashi; Kunihiro Okamura
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Molecular reproduction and development     Volume:  76     ISSN:  1098-2795     ISO Abbreviation:  Mol. Reprod. Dev.     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-01-26     Completed Date:  2009-08-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8903333     Medline TA:  Mol Reprod Dev     Country:  United States    
Other Details:
Languages:  eng     Pagination:  270-7     Citation Subset:  IM    
Department of Obstetrics and Gynecology, Tohoku University School of Medicine, Sendai, Japan.
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MeSH Terms
Centrosome / physiology*
Chromatin / metabolism
Embryo, Mammalian / metabolism,  ultrastructure
Micromanipulation / methods
Microscopy, Fluorescence
Microtubule-Organizing Center / metabolism
Microtubules / metabolism
Oocytes / metabolism*
Sperm Injections, Intracytoplasmic / methods*
Spermatids / metabolism*
Spermatozoa / metabolism*
Trimethoprim-Sulfamethoxazole Combination / metabolism
Tubulin / metabolism
Reg. No./Substance:
0/Chromatin; 0/Tubulin; 8064-90-2/Trimethoprim-Sulfamethoxazole Combination

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