Влияние сублетальных доз хлорида кадмия на развитие доимплантационных зародышей в двух поколениях мышей

Abstract

Cadmium is a heavy metal, highly toxic pollutant, entering the environment as a by-product of most modern industries. The effect of cadmium on the body depends on the route of entry, duration and dose of exposure. One of the important areas of this research is the study of the effect of cadmium on early development, leading to diseases in the adult body and possible developmental abnormalities in offspring. The aim of this study was to analyze the development of preimplantation embryos of mice exposed in utero to cadmium chloride and embryos obtained from cadmium-exposed parents. Preimplantation embryos of F1 (CBA×C57BL) hybrid mice exposed in utero to 30 µM of cadmium chloride (F1 — the first generation) and embryos of similar age, obtained from females and males, exposed in utero (F2 — the second generation), was studied. The toxic effect of cadmium chloride was studied by paternal, maternal and “double” (both parents were exposed) lines of inheritance. The development of embryos was assessed by the rate of blastomeres cleavage and the number of blastocysts. The F1 generation embryos exposed to cadmium chloride in utero passed the initial stages of cleavage and blastocyst formation faster compared to the control embryos. The development of the the maternal line second generation embryos (F2) was comparable with the control group. In the paternal and “double” (both parents were exposed) lines of inheritance, the rate of cleavage at the morula stage was slowdown, however, at the blastocyst stage, the rate of cleavage of embryos did not statistically differ from the control embryos. The effect of sublethal doses of cadmium chloride on famale mice at the onset of pregnancy affects not only the embryos of the first generation, directly exposed to cadmium chloride, but also the descendants of exposed parents in the second generation, slowing down the process of proliferation in the embryos of the paternal line of inheritance and in embryos born from two exposed parents. The results obtained in our model suggest that the harm from smoking caused by the accumulation of cadmium is manifested not only in children, but also in grandchildren. The epigenetic mechanism of such inheritance is most likely, which gives grounds for the development of preventive approaches to eliminate possible harmful consequences. It is advisable to recommend stopping smoking during pregnancy and in the period before conception.