Author
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LANOUE, L - UNIV. OF CALIFORNIA |
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STRONG, P - UNIV. OF CALIFORNIA |
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Hunt, Curtiss |
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KEEN, C - UNIV. OF CALIFORNIA |
Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only Publication Acceptance Date: 4/18/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Boron is a nutrient for which the limits of optimal intake remain to be defined. Boron is essential for plants, and recent studies suggest that boron is critical for early survival of frog and zebrafish embryos. the present study tests the effects of low, adequate and high exposures of boric acid (BA) on preimplantation mouse embryos. For boron essentiality, CD-1 mice were fed diets containing either low (0.04 ppm, OB) or adequate (2 ppm, 2B) levels of boron for a minimum of 10 weeks. After 10 and 12 weeks, 2-cell embryos were harvested from superovulated dams and cultured for 72h in 25 ul droplets of medium. A 10=week maternal dietary boron depletion was associated with a reduction in blastocyst formation (82%, OB) compared to boron adequate diet (93.6%, 2B); this difference was not seen at 12 week (88.9%, OB vs 91.9%, 2B). However, embryonic cell counts were consistently reduced following 10 and 12 weeks of treatment (67.7, OB vs 77.0, 2B). For boron toxicity, 2-cell embryos were cultured for 72h in medium containing graded levels of a BA (0, 6, 12, 25, 50, 100, 200, 400, 800,1000, 2000 uM). Significantly impaired embryonic differentiation and proliferation was observed only at the highest levels of BA exposure (1000 and 2000 uM) as shown by a significant reduction in blastocyst formation (84 vs 75 and 67%) and cell number (74.7 vs 53.4 and 47.7; 0, vs 1000 and 2000 uM BA). These data confirm a low order of boron toxicity during reproduction, and suggest hat boron deficient impairs early embryonic development in rodents. |