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.

Beneficial effects of L-arginine on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neuronal degeneration in substantia nigra of Balb/c mice.

BACKGROUND: L-arginine has been recently investigated and proposed to reduce neurological damage after various experimental models of neuronal cellular damage. In this study, we aim to evaluate the beneficial effects of L-arginine administration on the numerical density of dark neurons (DNs) in the substantia nigra pars compacta (SNc) of Balb/c mice subjected to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration. MATERIALS AND METHODS: Male Balb/c mice were randomly divided into 4 groups (n = 7 each): MPTP only; saline only (control); MPTP + L-arginine; and L-arginine only. The animals were infused intranasally with a single intranasal administration of the proneurotoxin MPTP (1 mg/nostril). L-arginine (300 mg/kg) was administrated intraperitoneally once daily for 1-week starting from 3 days after MPTP administration. Cavalieri principle method was used to estimate the numerical density of DNs in the SNc of different studied groups. RESULTS: Twenty days following MPTP administration, the number of DNs was significantly increased when compared to sham-control and L-arginine-control groups (P < 0.05). Nevertheless, our results showed that L-arginine administration significantly decreased the numerical density of DNs in SNc of mice. CONCLUSION: This investigation provides new insights in experimental models of Parkinson's disease, indicating that L-arginine represents a potential treatment agent for dopaminergic neuron degeneration in SNc observed in Parkinson's disease patients.

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 aqueous extract of turnip leaf (Brassica rapa) in alloxan-induced diabetic rats.

OBJECTIVES: Turnip leaf has been used in folk medicine of Iran for the treatment of diabetes. However,so far no scientific study has been done to support its use in traditional medicine. The present study was carried out to evaluate the possible hypoglycemic efficacy of aqueous extract of turnip leaf (AETL) in diabetic rats. MATERIALS AND METHODS: Alloxan-induced diabetic rats were orally treated with AETL at doses of 200 and 400 mg/kg body weight (bw) per day for 28 days. In order to evaluate the anti-diabetic activity, fasting blood glucose concentrations were determined on the 1(st), 14(th) and 29(th) days. Moreover,at the end of the study, plasma concentrations of total cholesterol, triglyceride (TG), high density lipoprotein cholesterol (HDL-c), low density lipoprotein cholesterol (LDL-c), aspartate amino transfarase (AST), and alanine amino transferase (ALT) were measured by the use of standard kits and auto-analyzer. RESULTS: Both doses of AETL significantly decreased (p<0.001) blood glucose and ALT levels in diabetic rats after 28 days of administration. AETL at both doses decreased (p<0.05) plasma total cholesterol and LDL-c in diabetic rats, but they significantly decreased (p<0.05) HDL-c and increased triglycerideand AST levels in a-dose dependent manner. CONCLUSION: The results showed that AETL has a dose- dependent decrease in the blood glucose in diabetic rats. However,we should not be unaware of adverse effects of AETL on lipid profiles and liver enzymes activity, especially decrease of HDL and increase of TG and AST.

Effects of L-arginine pre-treatment in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's diseases in Balb/c mice.

BACKGROUND: Parkinson's disease (PD) is a common neurodegenerative disease resulting from the degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc). Increasing evidence demonstrated that mice treated intranasally with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) suffered impairments in motor functions associated with disruption of DA neurons in SNc conceivably analogous to those observed in PD. L-arginine has been proposed as a novel neuroprotective agent that plays protective roles in several models of neuronal cellular damage. This study aimed to evaluate the effects of L-arginine on the numerical density of dark neurons (DNs) in the SNc of Balb/c mice subjected to MPTP administration. METHODS: In the present study, we demonstrated that repeated treatment with L-arginine (300 mg/kg, i.p.) during 7 consecutive days attenuated the production of DNs in SNc of adult male Balb/c mice infused with a single intranasal administration of MPTP (1 mg/nostril). RESULTS: Pre-treatment with L-arginine significantly decreased the numerical density of DNs in SNc of mice 21 days after intranasal MPTP administration. CONCLUSION: This investigation provides new insights in experimental models of PD, indicating that L-arginine represents a potential neuroprotective agent for the prevention of DA neuron degeneration in SNc observed in PD patients.