Japanese society of Ova Research

Abstract

Vol.16 No.3

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Effect of Gravity Load on Cortical Granule Distribution in the Mouse Oocyte
JMOR, 16(3) 104-109, 1999
DOI: 10.1274/jmor.16.104
1Laboratory of Animal Biotechnology, Faculty of Bioindustry, Tokyo University of Agriculture, Yasaka, Abashiri 099-2422 and 2Second Department of Anatomy, Toho University School of Medicine, Ota-ku, Tokyo 143-0015, Japan

In this study we investigated the effects of gravity over 1 G on the distribution of cortical granules (CGs) in mouse oocytes. We had found eggs incubated in a centrifuge culture medium showing a high rate of polyspermy, but there had been no difference between 2 G and 3 G loads in the incidence of polyspermy. We focused on cortical granules (CGs) which are known to act as a protection against polyspermy. The CG-free area of mouse oocytes subjected to increased G, when compared to that of control oocytes, was found to be significantly larger. Therefore, it can be assumed that the increased G caused an abnormal CG distribution which resulted in a high incidence of polyspermy in oocytes subjected to increased G. Further, as the centrifugation force was increased, the CGs free area of oocytes did not tend to expand. Observation was facilitated by using FITC-LCA fluorescent dye and TEM.

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