Feb 1, 1981

Sister-chromatid exchange analyses in rodent maternal, embryonic and extra-embryonic tissues: transplacental and direct mutagen exposures

Mutation Research
J W AllenR L Dixon

Abstract

Sister-chromatid exchange (SCE) analyses were conducted in maternal, embryonic and extraembryonic tissues of pregnant rats and mice. The various tissues were substituted in vivo with 5-bromodeoxyuridine (BrdU) by implantation of a BrdU tablet in pregnant animals at mid-gestation. Following maternal exposure to 5-20 mg/kg cyclophosphamide, embryonic liver cells demonstrated dose-dependent SCE increases up to 10-fold that of control. Rat embryos revealed little intralitter variability for this transplacental effect. Maternal marrow and yolk sac cells examined in the rat also underwent significant increases in SCE, although to different extents. While marrow SCE frequencies were similar to those of embryo liver, yolk sac SCE frequencies were generally much lower. SCE analyses were also conducted in rat yolk sac cells substituted in vivo with BrdU and subsequently explanted to whole-embryo culture. In vitro exposure to cyclophosphamide at concentrations up to 100 microgram/ml had no SCE-inducing effect. However, similar exposures to phosphoramide mustard, a presumed metabolite of cyclophosphamide, caused dose-dependent increases in SCE up to 8-fold higher than control at 2 microgram/ml. Thus, cyclophosphamide appears to require mat...Continue Reading

Mentioned in this Paper

Embryo
Mustard antigen
Cyclophosphamide
Entire Embryo
Sister Chromatid Exchange
Blastocyst Implantation, Natural
Pregnancy, Animal
Mustard preparation
Embryonic Tissue
Chromatids

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