Altered Uterine Perfusion is Involved in Fetal Outcome of Diabetic Rats

Abstract 

Maternal diabetes affects the development of the offspring by altering the uterine environment. We aimed to investigate the extent to which the blood flow (measured as Tissue Perfusion Units; TPU) to implantation sites and the expression of developmentally important genes in the offspring are affected by maternal diabetes. We measured mRNA levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), Bcl-2 associated X protein (Bax), B-cell lymphoma protein (Bcl-2), tumor suppressor protein-53 (p53), paired box protein-3 (Pax-3) and vascular endothelial growth factor-A (Vegf-A). Moreover, we studied the effect on uterine blood flow (TPU) and the expression of the genes exerted by embryonic maldevelopment (malformation or resorption). Streptozotocin induced diabetic (D) and non-diabetic (N) pregnant rats were used in the study. Blood flow (TPU) to implantation sites was measured by a laser Doppler flow meter, and gene expression was analyzed by RT-PCR. Maternal diabetes caused increased blood flow (TPU) to implantation sites compared with normal pregnancy. Furthermore, implantation sites of D rats containing malformed offspring showed impaired growth and decreased blood flow (TPU) compared with their littermates at all gestational days. Resorbed offspring from both N and D rats displayed increased blood flow (TPU) compared with their non-resorbed littermates. Moreover, we found that maternal diabetes causes decreased expression of genes involved in the oxidative stress defense system (CuZnSOD in non-malformed D11 embryos, MnSOD at all gestational time points, ECSOD and Gpx-1 at GD11–GD15, CAT and Gpx-2 at GD15), decreased expression of Pax-3 at GD11, and increased expression of Vegf-A at all gestational time points. We conclude that both maternal metabolism and embryonic developmental state affect the blood flow (TPU) to the implantation site. Maternal diabetes causes decreased expression of anti-oxidative enzymes and enhanced angiogenesis in the offspring in rats.

Keywords: Maternal diabetes, Blood flow (TPU), SOD, CAT, GPX, Bax, Bcl-2, p53, Vegf-A

Abbreviations: CAT, catalase, CR, crown rump length, D, diabetic rat, DEPC, diethyl pyrocarbonate, GD, gestational day, GPX, glutathione peroxidase, G6PDH, glucose-6-phosphate dehydrogenase, i.v., intravenous, N, non-diabetic control rat, SZ, streptozotocin, TPU, Tissue Perfusion Units, Vegf-A, vascular endothelial growth factor-A