Developmental-stage-dependent teratogenic effects of maternal spontaneous diabetes in the chinese hamster

The effect of maternal diabetes on teratogenesis was examined utilizing female Chinese hamsters with typical diabetic symptoms from our closed colony (CHA) and F13-F19 of the brother-sister mating generations of a diabetic strain (CHAD). Both groups were mated with nondiabetic males from CHA. Embryologic studies on day 2.5, 4.5, and 18.5 of gestation were performed with 30, 31, 71 diabetic females that were impregnated during a normal 4-day estrous cycle. The preimplantation embryos of day 2.5 and 4.5 were also karyotyped. The results indicated that: (1) There was no decrease in the number of ovulated ova, of collected embryos, and of implantation sites in the diabetic females. (2) As far as the preimplantation stages were concerned, there was no decrease in the cleavage activity and no increase in the incidence of developmental anomalies. (3) There was no increase of chromosomal aberrations in the preimplantation embryos. (4) With respect to the postimplantation development, however, there were significant increases in embryonic death (P less than 0.001), gross malformation (P less than 0.001), and fetal hypoplasia (P less than 0.001). Results (1), (2), and (3) indicated that in diabetic females capable of conceiving during a normal estrous cycle, the maternal diabetic milieu did not affect oogenesis, ovulation, fertilization, cleavage division, implantation, and chromosomal behavior. Result (4), however, showed definitely that maternal diabetes exerted deleterious effects on fetal development during the stage of organogenesis, and also markedly reduced fetal growth during later developmental stages.