The possible role of insulin-like growth factors (IGFs) and their receptors (IGFRs) in the pathogenesis of diabetic embryopathy was investigated. Sexually mature female ICR mice of 6-8 weeks old were made diabetic by a single intraperitoneal injection with 200 mg/kg streptozotocin ten days prior to mating. Fallopian tubes and uterine tissues were obtained from the superovulated diabetic and normal mice 48, 72 and 96 hours following human chorionic gonadotropin (hCG) injection. The mRNA expression of IGF-1 and IGF-2 as well as their receptors was determined in the tissues using Real-time Polymerase Chain Reaction (Real-time PCR). The mRNA expression of IGF-1 in the fallopian tube and uterus of the diabetic mice was significantly lower 72 and 96 hours after hCG treatment, respectively, as compared to the controls. The mRNA expression of IGF-1R at 96 hours post-hCG treatment was significantly higher in the fallopian tube and lower in the uterus of the diabetic mice as compared to the controls. The mRNA expression IGF-2 in the fallopian tube was significantly higher 48 and 96 hours after hCG treatment, but was lower in the uterus of diabetic mice 96 hours after hCG treatment as compared to controls. The mRNA expression of IGF-2R in the diabetic mice was significantly higher 48 and 96 hours (the fallopian tube) and 48 hours (uterus) after hCG treatments as compared to the controls. In conclusion, an alteration in mRNA expression of IGFs and their receptors in the diabetic mice as observed in this study could possibly result in diabetic embryopathy.
The aim of the present study was to analyze the immunolocalization of insulin-like growth factor (IGF)-1 and IGF-2 and their receptors in the oviduct and uterus of control and diabetic mice. Sexually mature female ICR mice aged 6-8 weeks were rendered diabetic by streptozotocin (200 mg/kg, administered intraperitoneally). Oviductal and uterine tissues were obtained from the superovulated control and diabetic mice at 48, 72 and 96 h post-human chorionic gonadotropin (hCG) treatment. Localization of IGF-1, IGF-2, IGF-1R and IGF-2R was determined by immunohistochemistry and a semi-quantitative scoring of immunolabelling was performed using a standardized 5-point system. The immunohistochemical scorings for both IGF-1 and IGF-1R were significantly decreased in the oviducts of diabetic mice at 96 h post-hCG treatment. The scores for IGF-2 were significantly increased in the oviducts of diabetic mice at 48 and 72 h post-hCG treatment, and for IGF-2R at 72 h post-hCG treatment. However, there was no significant difference in the scores of IGFs and their receptors in the uterus of control and diabetic mice. In conclusion, the oviductal immunolabelling for IGFs and their receptors was significantly altered by maternal diabetes, which may be of importance in the pathogenesis of preimplantation diabetic embryopathy.