Diabetes Mellitus Effect on Murine Embryonic Development

The Kunming mice used in this study were obtained from the Laboratory Animal Centre of Sun Yat-Sen University (Guangzhou, China). Eight-week-old female mice were used to induce diabetes mellitus by injecting STZ (Sigma, MO, USA) dissolved in 0.01 M citrate buffer at a pH of 4.5 and a dose of 75 mg kg⁻¹ body weight for three consecutive days. Blood glucose levels were measured 7 days after STZ injection by Roche Accu-Chek Aviva Blood Glucose System (Roche, USA). Diabetes mellitus was defined as a non-fasting blood glucose level greater than 288 mg dl⁻¹ (16 mM) [17 (link)]. Control mice were maintained euglycaemic prior to and during pregnancy (4–8 mM). Two female mice were housed with one normal male mouse overnight in a cage. The day when vaginal plugs were observed was designated as embryonic day 0.5 (E0.5). During pregnancy, blood glucose levels were monitored every 6 days. At E13.5 and E18.5, the embryos were dissected by Caesarean section after the pregnant mice were anaesthetized by an intraperitoneal injecting pentobarbital (150 mg kg⁻¹ body weight) [18 (link)]. The experiments were performed in triplicates for the three embryonic days, with 24 mice assigned to control and pregestational diabetes mellitus (PGDM) groups.