Japanese Journal of Veterinary Research;Volume 33, Number 1-2

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HISTOCHEMICAL OBSERVATIONS OF LIPID DROPLETS IN MOUSE EMBRYOS

HISHINUMA, Mitsugu;TAKAHASHI, Yoshiyuki;KANAGAWA, Hiroshi

Permalink : http://hdl.handle.net/2115/2319
JaLCDOI : 10.14943/jjvr.33.1-2.51
KEYWORDS : lipid droplet;mouse;embryo

Abstract

Morphology of lipid droplets in 313 embryos of different developmental stages was examined. Embryos were obtained from spontaneously ovulated and superovulated mice of ddY strain. Sudan III was used to stain embryos so as to count the number of lipid droplets. Lipid droplets were classified into three groups according to the diameter : small (≦ 1.0μm), medium (1.1-3.0μm) and large (3.1-5.0μm). From the 2-cell stage to the expanded blastocyst, lipid droplets were found to be abundant. Numerous small lipid droplets were observed in all developmental stages. The number of medium and large lipid droplets increased with the development of embryos. The numbers of medium lipid droplets in the embryos at the 2-cell stage, 8-cell stage and expanded blastocyst were 0.5±0.4,11.2±3.3 and 60.3±3.2,respectively. Large lipid droplets were not observed in the 2-cell and 4-cell stages, but were found to be abundant in the morula and blastocyst. A sudden and significant increase in the number of medium and large lipid droplets was observed from the 8-cell stage to the morula (p<0.01). Similar increase of lipid droplets was also observed in morulae developed from 8-cell embryos in in vitro culture (p<0.01). The number of lipid droplets in expanded blastocysts was not affected by the ovulation methods.

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