Chromosome Analysis in Preimplantation Stage Embryos of Non‐Obese Diabetic (NOD) Mice

Abstract

Congenital malformations such as exencephaly occur at a high incidence in non-obese diabetic (NOD) mouse embryos (Otani et al., 1987a). Using in vitro culture and embryo transfer, genetic predispositions as well as environmental factors were suggested to be the causes (Tatewaki et al., 1987).Chromosomes of preimplantation embryos, cultured to transfer mutually between non-obese diabetic (NOD) and ICR mice, were analyzed as a clue to elucidate the cause of developmental anomalies. Among these preimplantation embryos, aneuploidy, mixoploidy and structural anomalies were found, but in incidence of chromosomal anomalies there was no significant difference, statistically, between preimplantation embryos from diabetic mothers and those from nondiabetic mothers. These findings are considered to show that no increase in developmental abnormality in chromosomes occurs during the preimplantation stage.

Chromosome Analysis of Postimplantation Stage Embryos for Studying Possible Causes of Developmental Abnormalities in Nonobese Diabetic Mice

“…However, the number of ex ternally abnormal embryos from diabetic mice (NOD-DM), and therefore the number of embryos with a high incidence of chromo somal anomalies, was notably larger than those from nondiabetic (NOD-N) mice (p < 0.005). In preimplatation stage embryos, in cidences of chromosomal abnormalities were not significantly different between those from diabetic and from nondiabetic mothers [21,22], Thus, the chromosomes of embryos from diabetic mice appeared to be influenced by long-term (i.e. pre-plus post implantation period: about 7 days) maternal diabetic conditions.…”

“…These changes suggested a signifi cant alteration of the hormonal environment in diabetic mice. To determine the genetic predisposition, chromosomes from the pre implantation stage were analyzed [22], and no significant increase in chromosomal aberra tions was found among these embryos.…”

Relationship between Associations of NOR and Chromosomal Anomalies in the Abnormal Embryos of Nonobese Diabetic and STZ-Diabetic Mouse

“…By using mutual intrauterine embryo transplantation between the NOD and the ICR mice, it is strongly suggested that the diabetic environ ment is a major cause, but that genetic predis position is also a cause of congenital malfor mation in the NOD fetus [19], To determine the genetic predisposition, chromosomes from the preimplantation stage were analyzed [22], and no significant increase in chromo somal aberrations was found among these em bryos. On the other hand, postimplatation stage embryos (day 12 of gestation) in diabetic (NOD-DM) and nondiabetic (NOD-N) mice had a high or similar incidence of chromo somal anomalies, respectively, in comparison with those of nondiabetic ICR mice.…”

Analysis of polyploid cells in mouse embryonic cells cultured under diabetic conditions

“…We previously reported on the chromosomes of preimplantationstage NOD and ICR embryos cultured to transfer mutually between NOD and ICR mice (Tatewaki et al 1989a;Otani et al 1991). There was no significant difference among the ratios of chromosomal abnormalities, suggesting that developmental abnormality did not occur at least in chromosomal level during the preimplantation stage.…”

“…We have also investigated the diabetic environment and genetic factors as causal mechanisms in these developmental anomalies in the offspring from diabetic mothers (Tatewaki et al 1989a(Tatewaki et al ,b, 1991(Tatewaki et al , 1995Otani et al 1991), as well as in the pathogenesis of diabetes (Kagohashi et al 2005a,b). A high incidence in chromosomal abnormalities, especially numerical abnormalities, was found in the externally abnormal embryos of diabetic non-obese-diabetic (NOD) mice ).…”