Effect of streptozotocin diabetes on polysomal aggregation and protein synthesis rate in the liver of pregnant rats and their offspring

Looking at the Future Through the Mother's Womb: Gestational Diabetes and Offspring Fertility

Altered nutrition or intrauterine exposure to various adverse conditions during fetal development or earlier in a mother's life can lead to epigenetic changes in fetal tissues, predisposing those tissues to diseases that manifest when offspring become adults. An example is a maternal obesity associated with gestational diabetes (GDM), where fetal exposure to a hyperglycemic, hyperinsulinemic, and/or hyperlipidemic gestational environment can provoke epigenetic changes that predispose offspring to various diseased conditions later in life. While it is now well established that offspring exposed to GDM have an increased risk of developing obesity, metabolic disorders, and/or cardiovascular disease in adult life, there are limited studies assessing the reproductive health of these offspring. This mini-review discusses the long-term effect of in utero exposure to GDM-associated adverse prenatal environment on the reproductive health of the offspring. Moreover, using evidence from various animal models and human epidemiological studies, this review offers molecular insight and understanding of how epigenetic reprogramming of genes culminates in reproductive dysfunction and the development of subfertility or infertility later in adult life.

In Vivo and In Vitro Models of Diabetes: A Focus on Pregnancy

Diabetes in pregnancy is associated with an increased risk of poor outcomes, both for the mother and her offspring. Although clinical and epidemiological studies are invaluable to assess these outcomes and the effectiveness of potential treatments, there are certain ethical and practical limitations to what can be assessed in human studies.Thus, both in vivo and in vitro models can aid us in the understanding of the mechanisms behind these complications and, in the long run, towards their prevention and treatment. This review summarizes the existing animal and cell models used to mimic diabetes, with a specific focus on the intrauterine environment. Summary of this review.

Advancements and challenges in generating accurate animal models of gestational diabetes mellitus

The maintenance of glucose homeostasis during pregnancy is critical to the health and well-being of both the mother and the developing fetus. Strikingly, approximately 7% of human pregnancies are characterized by insufficient insulin production or signaling, resulting in gestational diabetes mellitus (GDM). In addition to the acute health concerns of hyperglycemia, women diagnosed with GDM during pregnancy have an increased incidence of complications during pregnancy as well as an increased risk of developing type 2 diabetes (T2D) later in life. Furthermore, children born to mothers diagnosed with GDM have increased incidence of perinatal complications, including hypoglycemia, respiratory distress syndrome, and macrosomia, as well as an increased risk of being obese or developing T2D as adults. No single environmental or genetic factor is solely responsible for the disease; instead, a variety of risk factors, including weight, ethnicity, genetics, and family history, contribute to the likelihood of developing GDM, making the generation of animal models that fully recapitulate the disease difficult. Here, we discuss and critique the various animal models that have been generated to better understand the etiology of diabetes during pregnancy and its physiological impacts on both the mother and the fetus. Strategies utilized are diverse in nature and include the use of surgical manipulation, pharmacological treatment, nutritional manipulation, and genetic approaches in a variety of animal models. Continued development of animal models of GDM is essential for understanding the consequences of this disease as well as providing insights into potential treatments and preventative measures.

Possible mechanisms involved in the down-regulation of translation during transient global ischaemia in the rat brain

The striking correlation between neuronal vulnerability and down-regulation of translation suggests that this cellular process plays a critical part in the cascade of pathogenetic events leading to ischaemic cell death. There is compelling evidence supporting the idea that inhibition of translation is exerted at the polypeptide chain initiation step, and the present study explores the possible mechanism/s implicated. Incomplete forebrain ischaemia (30 min) was induced in rats by using the four-vessel occlusion model. Eukaryotic initiation factor (eIF)2, eIF4E and eIF4E-binding protein (4E-BP1) phosphorylation levels, eIF4F complex formation, as well as eIF2B and ribosomal protein S6 kinase (p70(S6K)) activities, were determined in different subcellular fractions from the cortex and the hippocampus [the CA1-subfield and the remaining hippocampus (RH)], at several post-ischaemic times. Increased phosphorylation of the alpha subunit of eIF2 (eIF2 alpha) and eIF2B inhibition paralleled the inhibition of translation in the hippocampus, but they normalized to control values, including the CA1-subfield, after 4--6 h of reperfusion. eIF4E and 4E-BP1 were significantly dephosphorylated during ischaemia and total eIF4E levels decreased during reperfusion both in the cortex and hippocampus, with values normalizing after 4 h of reperfusion only in the cortex. Conversely, p70(S6K) activity, which was inhibited in both regions during ischaemia, recovered to control values earlier in the hippocampus than in the cortex. eIF4F complex formation diminished both in the cortex and the hippocampus during ischaemia and reperfusion, and it was lower in the CA1-subfield than in the RH, roughly paralleling the observed decrease in eIF4E and eIF4G levels. Our findings are consistent with a potential role for eIF4E, 4E-BP1 and eIF4G in the down-regulation of translation during ischaemia. eIF2 alpha, eIF2B, eIF4G and p70(S6K) are positively implicated in the translational inhibition induced at early reperfusion, whereas eIF4F complex formation is likely to contribute to the persistent inhibition of translation observed at longer reperfusion times.

Prevention by L-arginine and polyamines of delayed development and embryotoxicity caused by chemically-induced diabetes in rats

Diabetes mellitus induction with alloxan at a dose of 110 mg/kg i.p. in rats on Day 4 of pregnancy causes delayed development and resorptions as signs of embryotoxicity. In the present study, the administration of human NPH insulin at doses of 1 to 5 U/d to rats or 1.0 mL of 10 mM L-arginine for 8 d, starting the day following diabetes induction, prevented embryotoxicity and delayed development. Similar results were obtained when the polyamines putrescine, spermidine, or spermine were administered at doses of 1.0 mL of a 10 microM solution to each rat daily. However, even though L-arginine and polyamines prevented adverse effects of severe diabetes on the conceptus, and caused normalization of glucose, beta-hydroxybutyrate levels remained elevated. These results support the hypothesis that the mechanisms of normal and altered development could be mediated by the action of polyamines.