Expression of apoptosis-regulatory genes in the hippocampus of rat neonates born to mothers with diabetes.

Diabetes during pregnancy impairs the development of the central nervous system (CNS) and causes cognitive and behavioral abnormalities in offspring. However, the exact mechanism by which the maternal diabetes affects the development of the brain remains to be elucidated. The aim of the present study was to investigate the effects of maternal diabetes in pregnancy on the expression of Bcl-2 and Bax genes and the numerical density of degenerating dark neurons (DNs) in the hippocampus of offspring at the first postnatal two weeks. Wistar female rats were maintained diabetic from a week before pregnancy through parturition and male offspring was sacrificed at P0, P7, and P14. Our findings demonstrated a significant down-regulation in the hippocampal expression of Bcl-2 in the diabetic group newborns (P < 0.05). In contrast, the mRNA expression of Bax was markedly up-regulated in the offspring born to diabetic dams at all of studied time-points (P < 0.05). Moreover, we found a striking increase in the numerical density of DNs in the various subfields of hippocampus of diabetic group pups (P < 0.05). The results of the present study revealed that maternal hyperglycemia during gestational period may result in disturbances in the expression of Bcl-2 and Bax genes as two important genes in neuronal apoptosis regulation and induces the production of DNs in the developing hippocampus of neonatal rats. These disturbances may be a reason for the cognitive, structural, and behavioral anomalies observed in offspring born to diabetic mothers. Furthermore, the control of maternal glycaemia by insulin administration in most cases normalized these negative impacts.

Diabetes during pregnancy enhanced neuronal death in the hippocampus of rat offspring.

BACKGROUND: Diabetes in pregnancy has a detrimental effect on central nervous system (CNS) development and is associated with an increased risk of short- and long-term neurocognitive impairment in the offspring. This study aimed to investigate the effect of maternal diabetes and also insulin treatment on the numerical density of apoptotic cells in rat neonate's hippocampi during the first two postnatal weeks. METHODS: Wistar female rats were maintained diabetic from a week before gestation through parturition and their male pup's brains were collected at postnatal days (P); P0, P7 and P14, equivalent to the third trimester in human. Numerical density of total neurons and percentage of apoptotic (TUNEL-positive) cells in different subfields of hippocampus (CA1, CA2, CA3, and DG) was calculated by stereological methods. RESULTS: Immediately after birth, we found a significantly decline in the total neuronal density only in hippocampal CA3 area in neonates born to diabetic animals (p<0.0001). Moreover, the number of neurons was significantly decreased in all hippocampal sub-regions of diabetic group pups when compared to control and insulin treated diabetic pups at both P7 and P14 (p<0.0001 each). Nevertheless, in diabetic group, the percentage of apoptotic cells in different subfields of hippocampus were higher in all studied time-points compared to control or insulin treated diabetic groups (p<0.0001 each). There were no significant differences either in the total number or apoptotic cells in the different hippocampal sub-fields between the insulin-treated diabetic group and controls (p>0.05). CONCLUSION: Our data indicate that diabetes in pregnancy induce the neuronal cell apoptosis in offspring hippocampus. Furthermore, the maternal glycaemia control by insulin treatment in the most cases normalized these effects.

Effects of resuscitation with air or oxygen on blood gas and cerebral SOD concentration in neonatal rats with intrauterine asphyxia / 中华急诊医学杂志

Objective To test the effects of restuscitation with air or oxygen on the blood gas and cerebral superoxide dismutase (SOD) concentration in neonatal rats with experimental intrauterine asphyxia. Method Seventy-seven neonatal rats were randomly (random number) divided into three experimental groups: sham operation group (SHAM), air resuscitation group (AR), and oxygen resuscitation group (OR). In groups AR and OR, animal models of intrauterine asphyxia were established and then resuscitated with air (AR) or oxygen (OR) for 30min. Comparison was made between groups including the mortality 0 hour after resuscitation, and the levels of blood gas and cerebral SOD concentrations 0 h, 6 h and 24 h after resuscitation. Results Mortality of neonatal rats in SHAM group, AR group and OR group were 0 (0/24), 0 (0/26) and 3.7% (1/27), respectively (P ＞0.05). The average levels of blood PaO2 in OR group and AR group 0 h after resuscitation were (69.2 ± 8.2)mmHg and (55.5±10.3) mmHg,respectively (P=0.004). Blood pH and PaCO2 and BE levels in OR group 0 h after resuscitation were not significantly different from those in AR group (P＞0.05). Blood pH, PO2, PCO2and BE levels in OR group were also not significantly different from those in AR group 6 h and 24 hours after resuscitation. The average concentrations of cerebral SOD in OR group 0 h and 6 hours after resucitation were (38.3±9.8) U/mgprot and (8.6±3.6) U/mgprot, and those in AR group were (53.8± 10.6) U/mgprot and (13.0±4.6) U/mgprot, respectively (P = 0.003, 0.04). The cerebral SOD concentration in OR group 24 hours after resuscitation was not significantly different from that in AR group (P＞0.05). The cerebral SOD concentrations in SHAM group 0 h,6 h and 24 hours after resuscitation were much higher than those in OR group and AR group (P＜0.05). Conclusions Resuscitation with air is as good as pure oxygen in neonatal resuscitation, in respect of early mortality and improvement of acidosis in neonatal rats after intrauterine asphyxia. Resuscitation with air will generate less radical oxygen species than pure oxygen in neonatal rats after intrauterine asphyxia.