Vitamin E improves learning performance and changes the expression of nitric oxide-producing neurons in the brains of diabetic rats

Molecular mechanisms underlying hyperglycemia associated cognitive decline

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia. DM can lead to a number of secondary complications affecting multiple organs in the body including the eyes, kidney, heart, and brain. The most common effect of hyperglycemia on the brain is cognitive decline. It has been estimated that 20-70% of people with DM have cognitive deficits. High blood sugar affects key brain areas involved in learning, memory, and spatial navigation, and the structural complexity of the brain has made it prone to a variety of pathological disorders, including T2DM. Studies have reported that cognitive decline can occur in people with diabetes, which could go undetected for several years. Moreover, studies on brain imaging suggest extensive effects on different brain regions in patients with T2D. It remains unclear whether diabetes-associated cognitive decline is a consequence of hyperglycemia or a complication that co-occurs with T2D. The exact mechanism underlying cognitive impairment in diabetes is complex; however, impaired glucose metabolism and abnormal insulin function are thought to play important roles. In this review, we have tried to summarize the effect of hyperglycemia on the brain structure and functions, along with the potential mechanisms underlying T2DM-associated cognitive decline.

Intracerebral Hemorrhage and Diabetes Mellitus: Blood-Brain Barrier Disruption, Pathophysiology, and Cognitive Impairments

There is a surge in diabetes incidence with an estimated 463 million individuals been diagnosed worldwide. Diabetes Mellitus (DM) is a major stroke-related comorbid condition that increases the susceptibility of disabling post-stroke outcomes. Although less common, intracerebral hemorrhage (ICH) is the most dramatic subtype of stroke that is associated with higher mortality, particularly in DM population. Previous studies have focused mainly on the impact of DM on ischemic stroke. Few studies have focused on impact of DM on ICH and discussed the blood-brain barrier disruption, brain edema, and hematoma formation. However, more recently, investigating the role of oxidative damage and reactive oxygen species (ROS) production in preclinical studies involving DM-ICH animal models has gained attention. But, little is known about the correlation between neuroinflammatory processes, glial cells activation, and peripheral immune cell invasion with DM-ICH injury. DM and ICH patients experience impaired abilities in multiple cognitive domains by relatively comparable mechanisms, which could get exacerbated in the setting of comorbidities. In this review, we discuss both the pathology of DM as a comorbid condition for ICH and the potential molecular therapeutic targets for the clinical management of the ICH and its recovery.

Vitamin E for the management of major depressive disorder: possible role of the anti-inflammatory and antioxidant systems

OBJECTIVES

Vitamin E has various functions in humans, including antioxidant, anti-inflammatory, anti-cancer, and anti-atherogenic actions, as well as direct effects on enzymatic activities and modulation of gene transcription. In addition to these functions, vitamin E is also important for the central nervous system, and its role in the prevention and/or treatment of some neurological diseases has been suggested. In particular, the role of vitamin E in the modulation of major depressive disorder (MDD) is an issue that has emerged in recent studies. Many factors have been implicated in the pathophysiology of this disorder, including inflammation, oxidative, and nitrosative stress.

METHODS

This narrative review discusses the involvement of inflammation, oxidative, and nitrosative stress in the pathophysiology of MDD and presents clinical and preclinical studies that correlate vitamin E with this psychiatric disorder.

RESULTS

We gathered evidence from clinical studies that demonstrated the relationship between low vitamin E status and MDD symptoms. Vitamin E has been reported to exert a beneficial influence on the oxidative and inflammatory status of individuals, factors that may account for the attenuation of depressive symptoms. Preclinical studies have reinforced the antidepressant-like response of vitamin E, and the mechanisms underlying its effect seem to be related to the modulation of oxidative stress and neuroinflammation.

CONCLUSION

We suggest that vitamin E has potential to be used as an adjuvant for the management of MDD, but more studies are clearly needed to ascertain the efficacy of vitamin E for alleviating depressive symptoms.

Evaluation of the modulation of nitric oxide synthase expression in the cerebellum of diabetic albino rats and the possible protective effect of ferulic acid

INTRODUCTION

Diabetes mellitus is a multisystem disease. Oxidative stress and nitric oxide isoforms are involved in diabetic pathogenesis. Ferulic acid is a natural substance that is distributed broadly in plants with strong potent properties.

THE AIM OF THE RESEARCH

This research was designed to study the possible protective role of ferulic acid on oxidative stress and different Nitric oxide synthase isoforms (NOS) in the cerebellum of streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Twenty-four albino male rats were randomly divided into equal four groups: control group, group 2 received ferulic acid orally (10 mg/kg), group 3 diabetic group, group 4 diabetic rats received ferulic acid. After 8 weeks, the left cerebellar hemisphere was taken for tissue homogenate for oxidative markers and real-time PCR for NOS isoforms. Paraffin sections of the right cerebellar hemisphere were stained with cresyl violet, Luxol fast blue and immnunohistochemically stained for neuronal NOS, inducible NOS and endothelial NOS.

RESULTS

Degenerative changes were seen in the cerebella of the diabetic rats with significant elevation of Malondialdehyde, Nitric Oxide, and decrease of Superoxide dismutase levels. nNOS expression decreased and iNOS expression increased significantly. The ferulic acid-treated group showed a reduction of the degenerative changes in the cerebellum with significant improvement in oxidative stress marker, an increase of nNOS expression, and a decrease of iNOS expression.

CONCLUSIONS

Ferulic acid improves cerebellar functional and histopathological changes induced by diabetes which can be attributed mainly to its anti-oxidative effect and its ability to modulate NOS isoforms.

Vitamin E prevents the cognitive impairments in post-traumatic stress disorder rat model: behavioral and molecular study

RATIONALE

Post-traumatic stress disorder (PTSD) is a psychiatric disorder developed after an exposure to severe traumatic events. Patients with PTSD suffer from different symptoms including memory impairment. In addition, PTSD is associated with oxidative stress. Vitamin E, a fat-soluble vitamin, possesses cognition protective effects via its antioxidative properties.

OBJECTIVES

To investigate the impact of vitamin E on memory impairment induced by PTSD in animals.

METHODS

A rat model of PTSD-like behavior and the radial arm water maze (RAWM) for testing of learning and memory paradigm were used. Rats were divided into 4 groups: control, vitamin E, PTSD, and vitamin E + PTSD.

RESULTS

In the learning phase, results showed no significant differences among experimental groups, indicating that PTSD-like behavior did not impair learning ability in rats. However, memory tests in the RAWM showed that PTSD-like animals had impairment in both short-term and long-term memories. Vitamin E, on the other hand, prevented this impairment of memory. With respect to oxidative stress, significant decreases were detected in reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, glutathione peroxidase (GPx) and catalase enzyme activities, global histone 3 acetylation, and brain derived neurotrophic factor (BDNF) levels in the PTSD-like animals group compared with other groups (P < 0.05). Vitamin E protected the reduction of these oxidative stress biomarkers, global histone 3 acetylation, and BDNF levels.

CONCLUSIONS

Vitamin E prevented memory impairment associated with PTSD-like behavior in animals, probably via its antioxidative properties, and preservation of epigenetic changes induced in PTSD-like animals.

Impaired HPA axis function in diabetes involves adrenal apoptosis and phagocytosis

PURPOSE

The aim of the present study was to analyze the involvement of oxidative stress and inflammation in the modulation of glucocorticoid production in the adrenal cortex of diabetic rats.

METHODS

Male Wistar rats were treated with or without streptozotocin (STZ, an insulinopenic model of diabetes) and either α-lipoic (90 mg/kg ip.), α-tocopherol (200 mg/kg po.) or with STZ and supplemented with insulin (STZ + INS: 2.5U/day) for 4 weeks. Oxidative/nitrosative stress parameters and antioxidant enzymes were determined in adrenocortical tissues. Apoptosis and macrophage activation were evaluated by immunohistochemistry (TUNEL and ED1⁺). Basal and ACTH-stimulated corticosterone production were assessed by RIA and plasma ACTH levels were determined by an immunometric assay.

RESULTS

Diabetic rats showed a diminished response to exogenous ACTH stimulation along with higher basal corticosterone and lower plasma ACTH levels. In the adrenal cortex we determined an increase in the levels of lipoperoxides, S-nitrosothiols, nitric oxide synthase activity and nitro-tyrosine modified proteins while catalase activity and heme oxygenase-1 expression levels were also elevated. Antioxidant treatments were effective in the prevention of these effects, and in the increase in the number of apoptotic and phagocytic (ED1⁺) cells detected in diabetic rats. No changes were observed in the STZ + INS group.

CONCLUSIONS

Generation of oxidative/nitrosative stress in the adrenal cortex of diabetic rats leads to the induction of apoptosis and the activation of adrenocortical macrophages and is associated with an elevated basal corticosteronemia and the loss of the functional capacity of the gland.

Posttraumatic stress disorder-type behaviors in streptozotocin-induced diabetic rats can be prevented by prolonged treatment with vitamin E

Anxiety and stress disorders, such as posttraumatic stress disorder (PTSD) have been described as debilitating comorbidities of diabetes. In the present study, we aimed to investigate anxiety-like behavior and the extinction and generalization of aversive memories in fear conditioning using a streptozotocin-induced model of diabetes (DBT). Moreover, considering that DBT animals present increased oxidative stress in brain areas related to anxiety and memory, we aimed to evaluate the effect of prolonged treatment with antioxidant vitamin E on behavioral parameters of anxiety and fear memory and on the diabetic condition. It was observed that DBT animals showed a deficiency in extinguishing the aversive memory in a fear conditioning test, along with a generalization of the fear memory. They also present a more pronounced anxiety-like behavior in the elevated plus maze test. VIT E treatment (300 mg/kg, p.o.) was not able to reduce hyperglycemia; however, it was able to block the anxiogenic-like behavior, also improving the deficit in the extinction of the aversive memory as well as blocking the generalization of such memory in a different context. Taken together, our data suggest that DBT animals are prone to extinction deficits and generalization of fear memories, behaviors which are observed in models of PTSD. Lastly, prolonged VIT E supplementation may be effective in the treatment of anxiety, extinction deficit and generalization of fear memories induced by the diabetic condition.

Hyperuricemia as a Protective Factor for Mild Cognitive Impairment in Non-Obese Elderly

Mild cognitive impairment (MCI) is regarded as incipient dementia. Patients with MCI have increased risk of later progressing to dementia. Blood uric acid (UA) is an important non-enzymatic antioxidant in peripheral circulation, and plays an unconfirmed protective role in MCI. Furthermore, obesity-induced inflammation, which affects UA metabolism and MCI onset, might regulate such protective role. Thus, the aim of the study was to determine the relationship of UA to MCI and the potential effect from inflammation. The study consisted of 933 MCI patients diagnosed by neuropsychological scales and 933 controls with normal cognitive function. All subjects were ≥ 60 years old. There were 378 obese subjects in MCI group and 410 obese subjects in control group. A relationship between lower serum UA levels and higher risk of MCI was found in all MCI patients and non-obese MCI patients (OR: 0.78, 95% CI: 0.72 ~ 0.86; OR: 0.66, 95% CI: 0.55 ~ 0.78), but not in obese MCI patients (OR: 0.94, 95% CI: 0.81 ~ 1.12). Serum UA and hypersensitive C reactive protein (hs-CRP) levels were higher in obese MCI patients than in non-obese MCI patients (P < 0.001 and P < 0.001). Serum UA levels showed a positive linear correlation with serum hs-CRP levels in obese MCI patients (r = 0.284, P < 0.001), but not in non-obese MCI patients (r = 0.030, P = 0.481). In conclusion, we show the significant association between lower serum UA levels and higher risk of MCI in non-obese subjects. Obesity-induced inflammation may weaken such relationship.

Comparison on hypoglycemic and antioxidant activities of the fresh and dried Portulaca oleracea L. in insulin-resistant HepG2 cells and streptozotocin-induced C57BL/6J diabetic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Fresh Portulaca oleracea L. (family: Portulacaceae; POL) has been used as a folk medicine for the treatment of diabetes mellitus for a long time. More bioactive components with higher activity could be retained in fresh medicinal herbs compared to the dried ones. The present study was conducted to compare different antidiabetic activity between fresh and dried POL, including hypoglycemic and antioxidant activities both in vivo and in vitro. Furthermore, in order to explore which components were responsible for the antidiabetic activity, the difference on chemical components between fresh and dried POL was analyzed and compared.

MATERIALS AND METHODS

Insulin-resistant HepG2 cells induced by insulin were used to evaluate the promoting effect of the fresh and dried POL on glucose utilization in vitro. Streptozotocin (STZ)-induced C57BL/6J diabetic mice were used to compare the differences on hypoglycemic and antioxidant activities of fresh and dried POL, including the fasting blood glucose, glucose tolerance, serum insulin level, malondialdehyde (MDA) level and superoxide dismutase (SOD) activity in vivo. UPLC/Q-TOF-MS method was performed to analyze the difference of antidiabetic components between fresh and dried POL.

RESULTS

Compared with the dried POL extract, the fresh POL extract significantly increased the consumption of extracellular glucose in insulin-resistant HepG2 cells (P<0.05). In STZ-induced C57BL/6J diabetic mice, both fresh and dried extracts decreased markedly the fasting blood glucose (FBG) levels, and improved significantly oral glucose tolerance test (OGTT), as well as enhanced significantly insulin secretion and antioxidative activities (P<0.05; P<0.01). Furthermore, the fresh extract showed stronger antidiabetic activity (P<0.05). The UPLC/Q-TOF-MS analysis results also revealed that the relative contents of polyphenols and alkaloids in the fresh herbs were more abundant than those in the dried POL.

CONCLUSION

Our results indicated that both fresh and dried POL possessed antidiabetic activities, besides stronger activity was observed in the fresh herb. These findings provided evidence for the application and development of fresh POL in the treatment of diabetes mellitus.

Vitamin E ameliorates neurodegeneration related phenotypes caused by neurotoxicity of Al2O3-nanoparticles in C. elegans

Vitamin E has the potential to ameliorate the neurotoxicity of Al₂O₃-nanoparticles that induce neurodegeneration related phenotypes inC. elegans.

Diabetes Mellitus, Cognitive Impairment, and Traditional Chinese Medicine

Diabetes mellitus (DM) is a metabolic disorder affecting a large number of people worldwide. Numerous studies have demonstrated that DM can cause damage to multiple systems, leading to complications such as heart disease, cancer, and cerebrovascular disorders. Numerous epidemiological studies have shown that DM is closely associated with dementia and cognition dysfunction, with recent research focusing on the role of DM-mediated cerebrovascular damage in dementia. Despite the therapeutic benefits of antidiabetic agents for the treatment of DM-mediated cognitive dysfunction, most of these pharmaceutical agents are associated with various undesirable side-effects and their long-term benefits are therefore in doubt. Early evidence exists to support the use of traditional Chinese medicine (TCM) interventions, which tend to have minimal toxicity and side-effects. More importantly, these TCM interventions appear to offer significant effects in reducing DM-related complications beyond blood glucose control. However, more research is needed to further validate these claims and to explore their relevant mechanisms of action. The aims of this paper are (1) to provide an updated overview on the association between DM and cognitive dysfunction and (2) to review the scientific evidence underpinning the use of TCM interventions for the treatment and prevention of DM-induced cognitive dysfunction and dementia.

Neuroprotective effect of ginger in the brain of streptozotocin-induced diabetic rats

Diabetes mellitus results in neuronal damage caused by increased intracellular glucose leading to oxidative stress. Recent evidence revealed the potential of ginger for reducing diabetes-induced oxidative stress markers. The aim of this study is to investigate, for the first time, whether the antioxidant properties of ginger has beneficial effects on the structural brain damage associated with diabetes. We investigated the observable neurodegenerative changes in the frontal cortex, dentate gyrus, and cerebellum after 4, 6, and 8 weeks of streptozotocin (STZ)-induced diabetes in rats and the effect(s) of ginger (500 mg/kg/day). Sections of frontal cortex, dentate gyrus, and cerebellum were stained with hematoxylin and eosin and examined using light microscopy. In addition, quantitative immunohistochemical assessments of the expression of inducible NO synthase (iNOS), tumor necrosis factor (TNF)-α, caspase-3, glial fibrillary acidic protein (GFAP), acetylcholinesterase (AChE), and Ki67 were performed. Our results revealed a protective role of ginger on the diabetic brain via reducing oxidative stress, apoptosis, and inflammation. In addition, this study revealed that the beneficial effect of ginger was also mediated by modulating the astroglial response to the injury, reducing AChE expression, and improving neurogenesis. These results represent a new insight into the beneficial effects of ginger on the structural alterations of diabetic brain and suggest that ginger might be a potential therapeutic strategy for the treatment of diabetic-induced damage in brain.

Diabetes cognitive impairments and the effect of traditional chinese herbs

The problem of cognitive impairment resulting from diabetes is gaining more acceptance and attention. Both type 1 and type 2 diabetes mellitus have been proved to be associated with reduced performance on numerous domains of cognitive function. Although the exact mechanisms of cognitive impairments in diabetes have not been completely understood, hyperglycemia and insulin resistance seem to play significant roles. And other possible risk factors such as hypoglycemia, insulin deficiency, vascular risk factors, hyperactive HPA axis, depression, and altered neurotransmitters will also be examined. In the meanwhile, this review analyzed the role of the active ingredient of Chinese herbal medicine in the treatment of diabetes cognitive impairments.

The effect of Chinese Jinzhida recipe on the hippocampus in a rat model of diabetes-associated cognitive decline

Background

To investigate the effects of treatment with Multi component Chinese Medicine Jinzhida (JZD) on behavioral deficits in diabetes-associated cognitive decline (DACD) rats and verify our hypothesis that JZD treatment improves cognitive function by suppressing the endoplasmic reticulum stress (ERS) and improving insulin signaling transduction in the rats’ hippocampus.

Methods

A rat model of type 2 diabetes mellitus (T2DM) was established using high fat diet and streptozotocin (30 mg/kg, ip). Insulin sensitivity was evaluated by the oral glucose tolerance test and the insulin tolerance test. After 7 weeks, the T2DM rats were treated with JZD. The step-down test and Morris water maze were used to evaluate behavior in T2DM rats after 5 weeks of treatment with JZD. Levels of phosphorylated proteins involved in the ERS and in insulin signaling transduction pathways were assessed by Western blot for T2DM rats’ hippocampus.

Results

Compared to healthy control rats, T2DM rats initially showed insulin resistance and had declines in acquisition and retrieval processes in the step-down test and in spatial memory in the Morris water maze after 12 weeks. Performance on both the step-down test and Morris water maze tasks improved after JZD treatment. In T2DM rats, the ERS was activated, and then inhibited the insulin signal transduction pathways through the Jun NH2-terminal kinases (JNK) mediated. JZD treatment suppressed the ERS, increased insulin signal transduction, and improved insulin resistance in the rats’ hippocampus.

Conclusions

Treatment with JZD improved cognitive function in the T2DM rat model. The possible mechanism for DACD was related with ERS inducing the insulin signal transduction dysfunction in T2DM rats’ hippocampus. The JZD could reduce ERS and improve insulin signal transduction and insulin resistance in T2DM rats’ hippocampus and as a result improved the cognitive function.

The effects of the Chinese medicine ZiBu PiYin recipe on the hippocampus in a rat model of diabetes-associated cognitive decline: a proteomic analysis

AIMS/HYPOTHESIS

Increasing evidence suggests that diabetes is associated with an enhanced risk of cognitive decline. The precise mechanisms underlying diabetes-associated cognitive decline (DACD) remain unclear. Here we investigated the molecular changes associated with DACD using a comparative proteomics study of hippocampus in a rat model of type 2 diabetes. In addition, we tested the effects of the Chinese medicine ZiBu PiYin recipe (ZBPYR) on DACD.

METHODS

The hippocampus was dissected from control, diabetic and diabetic rats treated with ZBPYR (DM/ZBPYR). Soluble proteins were separated using fluorescence-based difference gel electrophoresis. Protein spots were visualised with fluorescent dyes and spot density was compared between each pair of groups. Proteins of interest were identified using mass spectrometry. Proteins of specific interest were also tested by western blot and real-time PCR analysis.

RESULTS

We found 13 spots that were altered between control and diabetes groups, and 12 spots that were changed between diabetes and DM/ZBPYR groups. The identities of nine proteins were determined by mass spectrometry. The identified proteins were largely involved in energy metabolism, cytoskeleton regulation and oxidative stress. The protein alterations observed in the diabetes group were ameliorated to varying degrees following ZBPYR treatment.

CONCLUSIONS/INTERPRETATION

The protein changes identified in hippocampus from a rat model of type 2 diabetes suggest that specific cellular alterations contribute to DACD. The Chinese medicine ZBPYR was found to affect multiple targets and partially repaired the original cellular balance. This study may provide important insights into the molecular events underlying DACD and allow the identification of novel therapeutic targets.

Alpha-tocopherol protects against memory impairment caused by L-NAME and modulates the injury marker and blood coagulant parameters

Cerebrovascular disease studies have shown similarity between humans and spontaneously hypertensive rats stroke-prone rats in the development of spontaneous stroke and transitory ischemic attacks (TIA). In addition, nitric oxide (NO) suppression by L-arginine methyl ester (L-NAME) can precipitate several vascular diseases including TIA and strokes. On the other hand, alpha-tocopherol (AT) has been associated with beneficial effects on vascular disorders. Four groups were tested to evaluate AT effects on NO inhibition: AT, control (C), AT + L-NAME, and L-NAME. During 4 weeks, all groups had their physiologic parameters evaluated and were submitted to neurological tests. After the sacrifice of the animals, total L-lactate dehydrogenase, fibrinogen levels, and platelet counts were measured. Our results demonstrated improvement in memory function and sensory-motor function of the rats treated with AT. The AT treatment also demonstrated a significant difference on the injury identifier, fibrinogen levels, and platelet count between the treated groups and the L-NAME group. In conclusion, AT reversed damaging L-NAME neurological effects and could be considered as a possible protective agent in neurological diseases.

The role of oxidative stress in fetal alcohol spectrum disorders

The ingestion of alcohol/ethanol during pregnancy can result in abnormal fetal development in both humans and a variety of experimental animal models. Depending on the pattern of consumption, the dose, and the period of exposure to ethanol, a myriad of structural and functional deficits can be observed. These teratogenic effects are thought to result from the ethanol-induced dysregulation of a variety of intracellular pathways ultimately culminating in toxicity and cell death. For instance, ethanol exposure can lead to the generation of reactive oxygen species (ROS) and produce an imbalance in the intracellular redox state, leading to an overall increase in oxidative stress. In the present review we will provide an up-to-date summary on the effects of prenatal/neonatal ethanol exposure on the levels of oxidative stress in the central nervous system (CNS) of experimental models of fetal alcohol spectrum disorders (FASD). We will also review the evidence for the use of antioxidants as potential therapeutic strategies for the treatment of some of the neuropathological deficits characteristic of both rodent models of FASD and children afflicted with these disorders. We conclude that an imbalance in the intracellular redox state contributes to the deficits seen in FASD and suggest that antioxidants are potential candidates for the development of novel therapeutic strategies for the treatment of these developmental disorders.

Prolonged treatment with vitamins C and E separately and together decreases anxiety-related open-field behavior and acoustic startle in hooded rats

Adult male and female hooded rats (about 110 days old) consumed vitamins C and E separately and combined together in their drinking water and were assessed for anxiety approximately 50 and then 80 days later in an open field and an acoustic startle apparatus. They were tested when 160+ days old, and then again at 190+ days. For both testing ages combined, the vitamins and their combination increased open-field ambulation and occupancy of the four center squares of the apparatus, while also accordingly decreasing occupancy of the four corners. Treatment with vitamins C and E separately and combined together also decreased acoustic startle amplitude. While there were several significant overall sex and testing age differences, there was no evidence that the vitamin treatment effects were dependent on the operation of either variable. There was also no evidence of synergism between vitamins C and E in their effects. It was suggested that decreases in anxiety produced by the vitamins may have arisen from their antioxidant properties, attenuation of cortisol activity or some as yet undetermined effects on anxiety-related brain structures and neurotransmitters.

Neonatal handling impairs spatial memory and leads to altered nitric oxide production and DNA breaks in a sex specific manner

Early life events lead to behavioral and neurochemical changes in adulthood. The aim of this study is to verify the effects of neonatal handling on spatial memory, nitric oxide (NO) production, antioxidant enzymatic activities and DNA breaks in the hippocampus of male and female adult rats. Litters of rats were non-handled or handled (10 min/day, days 1-10 after birth). In adulthood they were subjected to a Morris water maze or used for biochemical evaluations. Female handled rats showed impairment in spatial learning. They also showed decreased NO production, while no effects were observed in these parameters in male rats. No effects were observed on the number of hippocampal NADPH diaphorase positive cells. In the Comet Assay, male handled rats showed increased DNA breaks index when compared to non-handled ones. We conclude that neonatal handling impairs learning performance in a sex-specific manner, what may be related to NO decreased levels.