Protective role of endogenous ovarian hormones against learning and memory impairments and brain tissues oxidative damage induced by lipopolysaccharide

The inhibitory influence of carvacrol on behavioral modifications, brain oxidation, and general inflammation triggered by paraquat exposure through inhalation

The current study investigated how carvacrol (C) can prevent behavioral and brain oxidative changes, along with systemic inflammation caused by inhaled paraquat (PQ). Control rats exposed to saline solution, whereas six rat groups were subjected to PQ aerosols at a concentration of 54 mg/m3 in 16 days. The PQ-exposed groups received saline (PQ group), C at dosages of 20 (C-L) and 80 mg/kg/day (C-H), dexamethasone at a dosage of 0.03 mg/kg/day, pioglitazone at dose of 5 and 10 mg/kg/day (Pio-L and Pio-H), and a combination of C-L + Pio-L. Various parameters were assessed following the end of the treatment duration. There were marked elevation in total and differential white blood cell counts (WBCs), and malondialdehyde levels in the blood, hippocampus, and cerebral tissue but, thiol, superoxide dismutase (SOD), and catalase (CAT) exhibited a notable decrease (p < 0.05 to p < 0.001). The escape delay and traveled distance exhibited enhancement, however, on the probe day, the duration spent in the target quadrant and the time taken to enter the dark room at 3, 24, 48, and 72 hours post an electrical shock, showed a reduction in the PQ group (P<0.05 to P<0.001). Inhaled PQ-induced changes were significantly improved in C, Pio, Dexa, and C-L + Pio-L treated groups (P<0.05 to P<0.001). The effects of C-L + Pio-L on most measured variables were higher than C-L and Pio-L (P<0.05 to P<0.001). C improved PQ-induced changes similar to dexamethasone and C-L showed additive effects when administered in combination with Pio.

Morin Ameliorates Lipopolysaccharides-Induced Sepsis-Associated Encephalopathy and Cognitive Impairment in Albino Mice

Sepsis-associated encephalopathy is a common neurological complication of sepsis that is characterized by neuroinflammation, oxidative stress and apoptosis, which results in cognitive impairments in septic survivors. Despite numerous treatment options for this condition, none of them are definite. Therefore, this study aimed to investigate the impact of morin, a flavone known for its neuroprotective and anti-inflammatory effects, against lipopolysaccharides-induced sepsis-associated encephalopathy in albino mice for 7 days. Mice were divided into 4 groups: Negative control, morin, septic, and septic morin-treated mice. Sepsis was induced by a single injection of lipopolysaccharides (5 mg/kg, intraperitoneally), morin (50 mg/kg b. wt.) was given orally, starting from 5 h after sepsis induction, then daily for 4 other days. Morin ameliorated septic structural and functional alternations as manifested by improving the survival rate, the behavioral functions, in addition to preserving and protecting the brain tissue. This was accompanied with the augmentation of the total antioxidant capacity, as well as the suppression of tissue levels of the lipid peroxidation marker malondialdehyde, apoptosis (cleaved-caspase-3), glial fibrillary acidic protein, and the proinflammatory cytokine tumor necrosis factor. In conclusion, morin has a promising ameliorative effect to counteract the sepsis-associated encephalopathy via its anti-inflammatory and antioxidant effects and to prevent the associated cognitive impairments.

Sodium nitroprusside restored lipopolysaccharide-induced learning and memory impairment in male rats via attenuating inflammation and oxidative stress

Inflammation and oxidative stress upset memory. We explored influence of sodium nitroprusside (SNP) on memory deficits resulted from lipopolysaccharide (LPS).Groups include control, LPS, LPS + SNP 1 mg/kg, LPS + SNP 2 mg/kg, and LPS + SNP 3 mg/kg. Morris water maze and passive avoidance tests and biochemical measurements were carried out.In Morris water maze, LPS prolonged time and distance for finding the platform. In probe trial, it diminished time spent and traveled distance in the target zone. Injection of 2 and 3 mg/kg of SNP overturned the effect of LPS. In passive avoidance task, LPS postponed entrance into darkroom and reduced time spent in light room and incremented time spent in darkroom in 3, 24, and 72 h after electrical shock. All three doses of SNP restored the effects of LPS. Biochemical experiments confirmed that LPS elevated interleukin-6 and malondialdehyde concentration and declined total thiol content and superoxide dismutase and catalase activity in the hippocampus and cortex tissues. SNP particularly at a 3 mg/kg dose ameliorated LPS effects on these parameters.SNP attenuated memory disabilities resulting from LPS through modifying inflammation and boosting antioxidant defense.

Feeding metformin during pregnancy and lactation periods improved learning and memory impairment in the rat offspring exposed to febrile seizure: Role of oxidative stress and inflammatory response

BACKGROUND

Many clinical evidences have reported the higher risk of seizure in young children and infants after exposure to hyperthermia, which more likely can cause brain damage and affect cognitive function, so, many researches were focused on prevention or treatment of febrile seizure (FS) with minimal adverse effects. Considering the potential effects of oxidative stress as a prominent trigger in FS, and demonstrating the anti-oxidant effects of metformin, the present study aimed to investigate the protective effect of metformin administration in prenatal and lactation periods in rat pups exposed to hyperthermia by which induced seizure.

METHOD AND MATERIALS

Pregnant rats were divided into six groups: (1) vehicle: pregnant rats received normal saline during pregnancy and lactation; (2) FS: pregnant rats received normal saline during pregnancy and lactation; (3-5) FS-Met50/100/150 mg/kg: pregnant rats received different doses of metformin including 50, 100 and 150 mg/kg during pregnancy and lactation; (6) Met150 mg/kg: pregnant rats received Met150 mg/kg during pregnancy and lactation. The male pups born to mothers received in all FS groups exposed to hyperthermia. All experimental groups were allowed to grow up, and after the lactation period, they were subjected for behavioural tests and biochemical analysis.

RESULTS

According to the present findings, the prenatal and lactation exposure to the highest dose of metformin demonstrated significant difference with FS group in both behavioural and biochemical test analyses. Although the remaining doses of metformin were also effective, the much better results were reported with the highest dose of metformin (150 mg/kg). Interestingly, the highest dose of metformin administered alone demonstrated better result than vehicle in probe trial test.

CONCLUSION

Considering the present research and related study in relation to metformin in ameliorating the epilepsy symptoms, there are numerous evidences on positive effect of metformin on seizure. Although the exact mechanism is unclear, the anti-oxidant effect of metformin is strongly supported.

The effects of pioglitazone and rosiglitazone on liver function in hypothyroid rats

OBJECTIVES

This study aimed to investigate the antioxidant effect of rosiglitazone (ROG) and pioglitazone (POG) on oxidative damage and dysfunction of hepatic tissue in hypothyroid rats.

METHODS

The male rats were classified into six groups: (1) Control; (2) Hypothyroid, (3) Hypothyroid-POG 10, (4) Hypothyroid-POG 20, (5) Hypothyroid-ROG 2, and (6) Hypothyroid-ROG 4. To induction hypothyroidism in rats, propylthiouracil (PTU) (0.05 %w/v) was added to drinking water. In groups 2-6, besides PTU, the rats were also intraperitoneal administrated with 10 or 20 mg/kg POG or 2 or 4 mg/kg ROG for six weeks. Finally, after deep anesthesia, the blood was collected to measure the serum biochemical markers and hepatic tissue was separated for biochemical oxidative stress markers.

RESULTS

Administration of PTU significantly reduced serum thyroxin concentration, total thiol levels, activity of superoxide dismutase (SOD) and catalase (CAT) enzymes, and increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (Alk-P) and malondialdehyde (MDA) in the liver. Additionally, our results showed that prescription of POG or ROG for six weeks to hypothyroid rats resulted in an improvement in liver dysfunction (decrease in serum levels of AST, ALT, and ALK-P) through reducing oxidative damage in hepatic tissue (increase in CAT, SOD, or total thiols and decrease in MDA levels).

CONCLUSIONS

The findings of the present study presented that the IP administration of POG and ROG for six weeks improves liver dysfunction induced by hypothyroidism in juvenile rats by reducing oxidative damage.

Folic acid supplementation improved cognitive deficits associated with lithium administration during pregnancy in rat offspring

INTRODUCTION

The present study aimed to analyse both neurobehavioural and biochemical results of neonates born of mothers exposed to different doses of lithium along with the groups that received lithium at the highest dose with folic acid as a preventive treatment.

MATERIALS AND METHODS

Male and female rats were mated in separate cages, and pregnant rats were divided into eight first group as (1) vehicle; (2) propylthiouracil (PTU)-induced hypothyroidism; (3-4) received two different doses of lithium carbonate (15 and 30 mg/kg); (5-7) the highest doses of lithium (30 mg/kg) plus three different doses of folic acid (5, 10 and 15 mg/kg); and (8) received just folic acid (15 mg/kg). All treatments were dissolved in drinking water and continued until delivery, followed by returning to a regular diet without treatment.

RESULTS

Lithium (30 mg/kg) disrupts both behavioural and biochemical markers, including TSH, T3 and T4 as measuring indicators to assess thyroid function, IL-10 and TNF-α as anti-inflammatory and inflammatory agents, respectively, malondialdehyde as an oxidative stress marker, alongside SOD, and catalase activity as antioxidant indicators. Besides, folic acid, almost at the highest dose (15 mg/kg), attenuated memory impairement and anxiety-like behaviour caused by lithium. Moreover, the groups treated with folic acid alone in comparison with vehicles demonstrated higher levels of antioxidant and anti-inflammatory indicators.

CONCLUSION

According to the results, prenatal exposure to a high dose of lithium (30 mg/kg) leads to foetal neurodevelopmental disorder and growth restriction through various mechanisms more likely attributed to hypothyroidism, which means it should be either prohibited or prescribed cautiously during pregnancy.

Assessment of the neuroprotective effect of Cocos nucifera L. oil on learning and behavior impairment in ovariectomized rats

OBJECTIVE

The current study aimed to investigate whether Cocos nucifera L. oil (CO) is effective on menopause-related memory dysfunction in ovariectomized (OVX) rats.

MATERIALS AND METHODS

Fifty healthy female Wistar rats were randomly selected and classified into five groups as control, OVX rats, and three OVX groups of rats which received three different doses (100, 200, and 400 mg/kg/day) of CO for five consecutive weeks by gavage. To assess the effect of CO, neurobehavioral tests such as Morris water maze (MWM) and Passive avoidance (PA) were done and then the animals were sacrificed to remove cortical and hippocampal tissues for biochemical analysis.

RESULTS

In both behavioral tests including MWM and PA, treatment with CO particularly two higher doses of 200, and 400 mg/kg demonstrated significant improvement in comparison with OVX group. Furthermore, antioxidant biomarkers such as total thiol content, catalase and superoxide dismutase (SOD) activities were significantly higher in the OVX-CO groups versus the OVX group. On the contrary, malondialdehyde (MDA) concentration as an oxidative stress biomarker was remarkably lower in the OVX-CO200 and 400 mg groups than the OVX group.

CONCLUSION

The present study demonstrated the significant improvement of CO on learning and memory impairment induced by ovariectomy. Although the exact mechanism needs further investigation, it might have occurred due to the anti-oxidative effect of CO.

Sex-dependent deficits in associative learning across multiple LPS doses

Activation of the immune system by administration of the bacterial endotoxin lipopolysaccharide (LPS) impairs cognitive and neural plasticity processes. For instance, acute LPS exposure has been reported to impair memory consolidation, spatial learning and memory, and associative learning. However, the inclusion of both males and females in basic research is limited. Whether LPS-induced cognitive deficits are comparable in males and females is currently unclear. Therefore, the present study evaluated sex differences in associative learning following administration of LPS at a dose (i.e., 0.25 mg/kg) that impairs learning in males and higher LPS doses (i.e., 0.325 - 1 mg/kg) across multiple experiments. Adult male and female C57BL/6J mice were trained in a two-way active avoidance conditioning task following their respective treatments. Results showed that LPS had sex-dependent effects on associative learning. The 0.25 mg/kg LPS dose impaired learning in males, consistent with prior work. However, LPS, at any of the doses employed across three experiments, did not disrupt associative learning in females. Female mice were resistant to learning deficits despite showing heightened levels of select proinflammatory cytokines in response to LPS. Collectively, these findings demonstrate that the learning impairments resulting from acute LPS exposure are sex-dependent.

Feeding crocin ameliorate cognitive dysfunction, oxidative stress and neuroinflammation induced by unpredictable chronic mild stress in rats

INTRODUCTION

The aim of the current study was to investigate the probable mechanism and effect of crocin on brain oxidative damage and memory deficits induced by unpredictable chronic mild stress (UCMS).

MATERIALS AND METHODS

Male Wistar rats were randomly divided into six groups consisting of one vehicle group (received normal saline), four groups included rats who received UCMS 4 weeks out of which three groups were pretreated with different doses of crocin (10, 20, and 30 mg/kg/day) concomitantly. To assess the pure effect of crocin, the last experimental group received a high dose of crocin (30 mg/kg/day) without exposure to the UCMS procedure. The behavioral tests including Morris water maze (MWM) and passive avoidance (PA) were performed and eventually they were sacrificed for the estimation of biochemical parameters.

RESULTS

The increase in Malondialdehyde (MDA) as an oxidative stress indicator and nitrite levels in the hippocampus were observed in UCMS rats, along with memory deficits in behavioral tests including passive avoidance and Morris water maze (MWM) test. Moreover, treatment with crocin decreased MDA, nitrite, pro-inflammatory cytokine such as TNF-α, and pathological hallmark of Alzheimer's disease including amyloid-β (Aβ), and glial fibrillary acidic protein (GFAP) in the hippocampus, whereas antioxidant agents including total thiol content, SOD, and catalase activity were increased. Also behavioral test demonstrated a positive effect of crocin on memory deficit induced by UCMS. Interlukin-10 as an important anti-inflammatory agent was increased as well. Interestingly, in some behavioral and biochemical findings, treatment with 30 mg/kg of crocin has given better results compared to vehicle group, which means the administration of crocin could have preventive effects on learning and memory impairment.

CONCLUSION

The present study strongly confirmed the positive effect of crocin and has the potential as an antioxidant and anti-inflammatory agent that could improve memory impairment induced by UCMS.

The effects of vitamin D on cardiovascular damage induced by lipopolysaccharides in rats

INTRODUCTION

Inflammation and oxidative stress are contributed to cardiovascular diseases. Vitamin D (Vit D) has antioxidant and anti-inflammatory properties. In the current research, the effect of Vit D on cardiac fibrosis and inflammation, and oxidative stress indicators in cardiovascular tissues was studied in lipopolysaccharides(LPS) injected rats.

METHODS

Rats were distributed into 5 groups and were treated for 2 weeks. Control: received vehicle(saline supplemented with tween-80) instead of Vit D and saline instead of LPS, LPS: treated by 1 mg/kg of LPS and was given vehicle instead of Vit D, LPS-Vit D groups: received 3 doses of Vit D (100, 1000, and 10000 IU/kg) of Vit D in addition to LPS. Vit D was dissolved in saline supplemented with tween-80 (final concentration 0.1%) and LPS was dissolved in saline. The white blood cell (WBC) was counted. Oxidative stress markers were determined in serum, aorta, and heart. Cardiac tissue fibrosis was also estimated using Masson's trichrome staining method.

RESULTS

WBC and malondialdehyde (MDA) were higher in the LPS group than the control group, whereas the thiol content, superoxide dismutase (SOD), and catalase (CAT) were lower in the LPS group than the control group (P<0.01 and P<0.001). Administration of Vit D decreased WBC (P<0.001) and MDA (P<0.05 and P<0.001) while enhanced thiol (dose 10000 IU/Kg) (P<0.001), SOD (dose 10000 IU/kg) (P<0.001), and CAT (P<0.05 and P<0.001) compared to the LPS group. All doses of Vit D also decreased cardiac fibrosis compared to the LPS group (P<0.001).

CONCLUSION

Vit D protected the cardiovascular against the detrimental effect of LPS. This cardiovascular protection can be attributed to the antioxidant and anti-inflammatory properties of Vit D.

Targeting Estrogen Signaling in the Radiation-induced Neurodegeneration: A Possible Role of Phytoestrogens

Radiation for medical use is a well-established therapeutic method with an excellent prognosis rate for various cancer treatments. Unfortunately, a high dose of radiation therapy comes with its own share of side effects, causing radiation-induced non-specific cellular toxicity; consequently, a large percentage of treated patients suffer from chronic effects during the treatment and even after the post-treatment. Accumulating data evidenced that radiation exposure to the brain can alter the diverse cognitive-related signaling and cause progressive neurodegeneration in patients because of elevated oxidative stress, neuroinflammation, and loss of neurogenesis. Epidemiological studies suggested the beneficial effect of hormonal therapy using estrogen in slowing down the progression of various neuropathologies. Despite its primary function as a sex hormone, estrogen is also renowned for its neuroprotective activity and could manage radiation-induced side effects as it regulates many hallmarks of neurodegenerations. Thus, treatment with estrogen and estrogen-like molecules or modulators, including phytoestrogens, might be a potential approach capable of neuroprotection in radiation-induced brain degeneration. This review summarized the molecular mechanisms of radiation effects and estrogen signaling in the manifestation of neurodegeneration and highlighted the current evidence on the phytoestrogen mediated protective effect against radiationinduced brain injury. This existing knowledge points towards a new area to expand to identify the possible alternative therapy that can be taken with radiation therapy as adjuvants to improve patients' quality of life with compromised cognitive function.

Sexual dimorphism in spatial learning and brain metabolism after exposure to a western diet and early life stress in rats

Prolonged daily intake of Western-type diet rich in saturated fats and sugars, and exposure to early life stress have been independently linked to impaired neurodevelopment and behaviour in animal models. However, sex-specific effects of both environmental factors combined on spatial learning and memory, behavioural flexibility, and brain oxidative capacity have still not been addressed. The current study aimed to evaluate the impact of maternal and postnatal exposure to a high-fat and high-sugar diet (HFS), and exposure to early life stress by maternal separation in adult male and female Wistar rats. For this purpose, spatial learning and memory and behavioural flexibility were evaluated in the Morris water maze, and regional brain oxidative capacity and oxidative stress levels were measured in the hippocampus and medial prefrontal cortex. Spatial memory, regional brain oxidative metabolism, and levels of oxidative stress differed between females and males, suggesting sexual dimorphism in the effects of a HFS diet and early life stress. Males fed the HFS diet performed better than all other experimental groups independently of early life stress exposure. However, behavioural flexibility evaluated in the spatial reversal leaning task was impaired in males fed the HFS diet. In addition, exposure to maternal separation or the HFS diet increased the metabolic capacity of the prefrontal cortex and dorsal hippocampus in males and females. Levels of oxidative stress measured in the latter brain regions were also increased in groups fed the HFS diet, but maternal separation seemed to dampen regional brain oxidative stress levels. Therefore, these results suggest a compensatory effect resulting from the interaction between prolonged exposure to a HFS diet and early life stress.

The effects of curcumin in learning and memory impairment associated with hypothyroidism in juvenile rats: the role of nitric oxide, oxidative stress, and brain-derived neurotrophic factor

The effect of curcumin (Cur) on cognitive impairment and the possible role of brain tissue oxidative stress, nitric oxide (NO) levels, and brain-derived neurotrophic factor (BDNF) were investigated in juvenile hypothyroid rats. The juvenile rats (21 days old) were allocated into the following groups: (1) control; (2) hypothyroid (0.05% propylthiouracil (PTU) in drinking water); (3-5) hypothyroid-Cur 50, 100, and 150, which in these groups 50, 100, or 150 mg/kg, Cur was orally administered by gavage during 6 weeks. In the hypothyroid rats, the time elapsed and the traveled distance to locate the hidden platform in the learning trials of Morris water maze (MWM) increased, and on the probe day, the amount of time spent in the target quadrant and the distance traveled in there was decreased. Hypothyroidism also decreased the latency and increased the time spent in the darkroom of the passive avoidance (PA) test. Compared with the hypothyroid group, Cur enhanced the performance of the rats in both MWM and PA tests. In addition, Cur reduced malondialdehyde concentration and NO metabolites; however, it increased thiol content as well as the activity of catalase (CAT) and superoxide dismutase enzymes in both the cortex and hippocampus. Cur also increased hippocampal synthesis of BDNF in hypothyroid rats. The beneficial effects of Cur cognitive function in juvenile hypothyroid rats might be attributed to its protective effect against oxidative stress and potentiation of BDNF production.

Zingiber officinale (Ginger) hydroalcoholic extract improved avoidance memory in rat model of streptozotocin-induced diabetes by regulating brain oxidative stress

OBJECTIVES

Diabetes mellitus associated cognitive impairment is suggested to be due to oxidative stress. Considering the anti-diabetic, antioxidant, antihyperlipidemic, and anti-inflammatory effects of Zingiber officinale, the present study aimed to investigate its effect on memory and oxidative stress factors in streptozotocin (STZ)-induced diabetic rats.

METHODS

The rats were allocated into five groups: Control, Diabetic, Diabetic + Ginger 100, Diabetic + Ginger 200, and Diabetic + Ginger 400. Following diabetes induction by STZ (60 mg/kg), 100, 200, or 400 mg/kg Ginger was given for eight weeks. Passive avoidance test (PA) was done and thiol, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) measurements were carried out in the brain.

RESULTS

The latency into the dark compartment decreased (p<0.001) and the number of entries and time spent in the dark chamber increased in the Diabetic group compared to the Control (p<0.001 for all). All three doses of extract improved performance of the rats in the PA test (p<0.001 for all). The hippocampal and cortical MDA level was higher (p<0.001) while CAT, SOD, and total thiol were lower (p<0.01-p<0.001) in the Diabetic group than the Control. Treatment with 200 and 400 mg/kg Z. officinale extract reduced hippocampal and cortical MDA (p<0.001) and improved CAT (p<0.001) while, just the dose of 400 mg/kg of the extract increased SOD and total thiol in hippocampal and cortical tissues (p<0.001) compared with Diabetic group.

CONCLUSIONS

Z. officinale extract could improve memory by reducing the oxidative stress in STZ-induced diabetes model.

Metformin improved memory impairment caused by chronic ethanol consumption during adolescent to adult period of rats: Role of oxidative stress and neuroinflammation

OBJECTIVE

Adolescence is a crucial time for brain maturation. We investigated the protective effects of metformin (Met) on behavioral changes, oxidative stress, tumor necrosis factor alpha (TNF-α) and nitrite in adulthood induced by ethanol (Eth) consumption during adolescent to adult period of rats.

MATERIALS AND METHODS

The adolescence male rats (21 days old) were treated as: 1) Control, 2) Eth (Eth in drinking water (20 %)), 3-5) Eth-Met50, 100 and 150 mg/kg (Eth in drinking water and Met (50, 100, or 150 mg/kg). After 5 weeks treatment, Morris water maze (MMW) and passive avoidance (PA) tests were done.

RESULTS

The latency in the MWM test was higher and the latency to enter the dark chamber in the PA test was lower in the Eth group than in control. In Eth-Met100 and 150 groups, they were less than the Eth group. Malondialdehyde (MDA) and nitrite concentration in the hippocampus and cortex of the Eth group were higher than the control group. The thiol content and catalase and superoxide dismutase (SOD) activities in hippocampal and cortical tissues of the Eth group reduced compared to the control group. TNF-α was higher in hippocampal tissues of Eth group animals. Met reversed all of these effects.

CONCLUSION

Our findings showed that the protective effects of Met against chronic Eth consumption induced learning and memory impairment were accompanied by decreasing of TNF-a, nitrite and oxidative stress in adolescent rats.

Effect of vitamin E on cisplatin-induced memory impairment in male rats

OBJECTIVE

Neurotoxicity is an adverse effect caused by cisplatin due to inflammation and oxidative stress in the central nervous system. The present study aimed to assess the effects of vitamin E injection on the learning and memory of rats with cisplatin-induced cognitive impairment.

METHODS

Male rats were administered with cisplatin (2 mg/kg/7 day; intraperitoneally [i i.p.]) and/or vitamin E (200 mg/kg/7 day; i.p.) for 1 week, and the control group received saline solution. Spatial memory was evaluated using Morris water maze (MWM). In addition, the hippocampal concentrations of malondialdehyde (MDA), thiol, and superoxide dismutase (SOD) were measured using biochemical methods.

RESULTS

According to the findings, cisplatin significantly increased the escape latency, while decreasing the time spent and travelled pathway in the target quadrant on the final trial day compared to the control group. Furthermore, pre-treatment with vitamin E significantly reversed all the results in the spatial memory test. The biochemical data indicated that vitamin E could decrease MDA activity and increase thiol and SOD activity compared to the control group.

CONCLUSION

According to the results, vitamin E could improve cisplatin-induced memory impairment possibly through affecting the hippocampal oxidative status.

Neuronal Nitric Oxide Inhibitor 7-Nitroindazole Improved Brain-Derived Neurotrophic Factor and Attenuated Brain Tissues Oxidative Damage and Learning and Memory Impairments of Hypothyroid Juvenile Rats

Hypothyroidism-associated learning and memory impairment is reported to be connected to oxidative stress and reduced levels of brain-derived neurotrophic factor (BDNF). The effects of neuronal nitric oxide inhibitor 7-nitroindazole (7NI) on brain tissues oxidative damage, nitric oxide (NO), BDNF and memory impairments in hypothyroid juvenile rats were investigated. Male Wistar juvenile rats (20 days old) were divided into five groups, including Martinez et al. (J Neurochem 78 (5):1054-1063, 2001). Control in which vehicle was injected instead of 7NI, (Jackson in Thyroid 8 (10):951-956, 1998) Propylthiouracil (PTU) where 0.05% PTU was added in drinking water and vehicle was injected instead of 7NI, (Gong et al. in BMC Neurosci 11 (1):50, 2010; Alva-Sánchez et al. in Brain Res 1271:27-35, 2009; Anaeigoudari et al. in Pharmacol Rep 68 (2): 243-249, 2016) PTU-7NI 5, PTU-7NI 10 and PTU-7NI 20 in which 5, 10, or 20 mg/kg7NI was injected intraperitoneally (i.p.). Following 6 weeks, Morris water maze (MMW) and passive avoidance learning (PAL) tests were used to evaluate the memory. Finally, the hippocampus and the cortex of the rats were removed after anesthesia by urethane to be used for future analysis. The escape latency and traveled path in MWM test was increased in PTU group (P < 0.001). PTU also reduced the latency to enter the dark box of PAL and the time spent and the distance in the target quadrant in MWM test (P < 0.001 and P < 0.01). Treatment with 7NI attenuated all adverse effects of PTU (P < 0.05 to P < 0.001). PTU lowered BDNF and thiol content and superoxide dismutase (SOD) and catalase (CAT) activities in the brain but increased malondialdehyde (MDA) and nitric oxide (NO) metabolites. In addition, 7NI improved thiol, SOD, CAT, thiol, and BDNF but attenuated MDA and NO metabolites. The results of the current study showed that 7NI improvement in the learning and memory of the hypothyroid juvenile rats, which was accompanied with improving of BDNF and attenuation of NO and brain tissues oxidative damage.

Inducible nitric oxide synthase inhibitor, aminoguanidine improved Ki67 as a marker of neurogenesis and learning and memory in juvenile hypothyroid rats

INTRODUCTION

In the present study, the effect of inducible nitric oxide (NO) synthase inhibitor, aminoguanidine (AG) on neurogenesis indicators, learning and memory, and oxidative stress status in juvenile hypothyroid (Hypo) rats was evaluated.

METHOD

The studied groups were including: (a) Control, (b) Hypo, (c-e) Hypo-AG 10, Hypo-AG 20, and Hypo-AG 30. Hypothyroidism was induced in the groups 2-5 by adding propylthiouracil in drinking water (0.05%). AG (10, 20, or 30 mg/kg) was daily injected intraperitoneally in the groups 3-5. The rats of the groups 1 and 2 were injected by saline instead of AG. After 6 weeks treatment, Morris water maze (MMW) and passive avoidance (PA) tests were done. Deep anesthesia was then induced and the brain tissue was excised for biochemical parameters measuring.

RESULTS

Ki67 as a maker of neurogenesis and thiol, superoxide dismutase (SOD), and catalase (CAT) as oxidative stress indicators were decreased in the brain of Hypo group, whereas malondialdehyde (MDA) and NO metabolites were enhanced. AG improved Ki67, thiol, CAT, and SOD while decreased MDA and NO metabolites. The escape latency in the MWM test increased in the Hypo group. The spending time in the target quadrant in the probe test of MWM and step-through latency in the PA test in the Hypo group was lower than Control group. AG reversed all the negative behavioral effects of hypothyroidism.

CONCLUSION

These results revealed that AG improved neurogenesis, learning and memory impairments, and oxidative imbalance in the brain juvenile Hypo rats.

Protective Effects of Carvacrol on Brain Tissue Inflammation and Oxidative Stress as well as Learning and Memory in Lipopolysaccharide-Challenged Rats

Inflammation can cause memory impairment. In the present study, the effect of carvacrol on brain tissue inflammation and oxidative stress as well as learning and memory in lipopolysaccharide (LPS)-challenged rats was evaluated. The animals were grouped and treated: (1) control which received vehicle instead of LPS and carvacrol, (2) LPS (1 mg/kg; i.p. 120 min before behavioral tests), and (3-5) in these groups, 25, 50, or 100 mg/kg of carvacrol (i.p.) was administered 30 min prior to LPS. In a Morris water maze test, compared to LPS group, administration of all three doses of carvacrol shortened the elapsed time and the traveled distance to find the platform, while it prolonged the traveled time in the target area. In a passive avoidance test, administration of all 25, 50, and 100 mg/kg carvacrol significantly increased the latency at the 3 h, 24 h, 48 h, and 72 h after the shock compared to the LPS group. Interleukin (IL)-6, malondialdehyde (MDA), and NO (nitric oxide) metabolites were increased in the brain by LPS injection, while thiol, superoxide dismutase (SOD), and catalase (CAT) were decreased. Pretreatment with carvacrol reduced IL-6, NO metabolites, and MDA, while it improved thiol content, CAT, and SOD. The results indicated that carvacrol protected from learning and memory impairment and the brain tissue inflammation and oxidative stress in LPS-challenged rats.

Inducible nitric oxide inhibitor aminoguanidine, ameliorated oxidative stress, interleukin-6 concentration and improved brain-derived neurotrophic factor in the brain tissues of neonates born from titanium dioxide nanoparticles exposed rats

Introduction: An interaction between oxidative stress, neuroinflammation, and nitric oxide (NO) has been suggested to have a role neurotoxicity. The aim of current research was to investigate the effect of aminoguanidine (AG) as an inducible NO synthase (iNOS) inhibitor, on brain-derived neurotrophic factor (BDNF), oxidative stress, and interleukin-6 (IL-6) concentrations in the brain tissues of neonates born from the rats exposed to titanium dioxide nanoparticles (TiO2 NPs) during gestation. Methods: The pregnant rats were grouped into three and received: (1) saline, (2) TiO2 (200 mg/kg, gavage), and (3) TiO2-AG [200 mg/kg intraperitoneal (IP)]. The treatment was started since the second gestation day up to the delivery time. The neonates born from the rats were deeply anesthetized, sacrificed, and the brains were collected for biochemical evaluations. Results: The neonates born from the rats exposed to TiO2 showed a lower BDNF (p < .001) but a higher IL-6 (p < .01) concentrations in their hippocampal tissue. TiO2 exposure also increased malondialdehyde (MDA) (p < .001) and NO metabolites (p < .001), while diminished thiol (p < .001), superoxide (SOD) (p < .001), and catalase (CAT) (p < .001) in all hippocampal, cortical, and cerebellar tissues. Administration of AG improved BDNF (p < .01) but attenuated IL-6 (p < .01) concentrations in the hippocampal tissue. AG also decreased MDA (p < .001) and NO metabolites (p < .01-p < .001), while increased thiol (p < .01-p < .001), SOD (p < .001), and CAT (p < .05-p < .001) in all cerebellar, hippocampal, cortical, and tissues. Conclusion: The results of the current research revealed that iNOS inhibitor AG, ameliorated oxidative stress, IL-6 concentration, and improved BDNF in the brain tissues of neonates born from TiO2 NPs exposed rats.

Effects of PPAR-γ agonist, pioglitazone on brain tissues oxidative damage and learning and memory impairment in juvenile hypothyroid rats

Aim: The effect of peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist pioglitazone on the brain tissues oxidative damage and learning and memory impairment in the juvenile hypothyroid rats was evaluated. Main methods: Rats were classified as: ( 1 ) Control; (2) Propylthiouracil (PTU); (3) PTU-Pio 10 and (4) PTU-Pio 20. PTU was given in drinking water (0.05%) during 6 weeks. Pioglitazone (10 or 20 mg/kg) was daily injected intraperitoneally. Passive avoidance (PA) and Morris water maze (MMW) were conducted. Later, the animals were sacrificed and the brain tissues were removed for biochemical measurements. Key funding: The results indicated that in the MWM escape latency as well as traveled path increased in the PTU group as compared to the control group. Also, the time spent in the target quadrant in the probe test of MWM and step-through latency in the PA test were decreased in the PTU group as compared to the control group. Pioglitazone reversed all the negative behavioral effects of hypothyroidism. Administration of PTU attenuated thiol and superoxide dismutase (SOD), and catalase (CAT) activities in the brain tissues, whereas increased malondialdehyde (MDA) and nitric oxide (NO) metabolites. PPARγ agonist improved thiol, SOD and CAT, while diminished MDA concentration. Significance: Our finding in the present study indicated that PPARγ agonist pioglitazone prevented the brain tissues from oxidative damage and learning and memory impairments in juvenile hypothyroid rats.

Memory enhancing effect of Nigella Sativa hydro-alcoholic extract on lipopolysaccharide-induced memory impairment in rats

In this study, the effects of Nigella Sativa (NS) hydro-alcoholic extract on lipopolysaccharide (LPS)-induced learning and memory impairments, hippocampal cytokine levels, and brain tissues oxidative damage were investigated in rats. The rats were grouped and treated: (1) control (saline), (2) LPS (1 mg/kg i.p.), and (3-5) 100, 200, or 400 mg/kg NS hydro-alcoholic extract 30 min before LPS injection. The treatment was started since 6 days before the behavioral experiments and continued during the behavioral tests (LPS injection 2 h before each behavioral experiment). Finally, the brains were removed for biochemical assessments. In Morris water maze (MWM) test, LPS increased the escape latency and traveled path compared to control group, whereas all doses of NS hydro-alcoholic extract decreased them compared to LPS group. In passive avoidance (PA) test, the latency to enter the dark compartment in LPS group was shorter than control group while in all treated groups it was longer than LPS group. LPS increased tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), and nitric oxide (NO) metabolites, and decreased thiol content, superoxide dismutase (SOD), and catalase (CAT) in the hippocampal tissues compared to control group while NS hydro-alcoholic extract decreased MDA and NO metabolites and increased thiol content, SOD, and CAT compared to LPS group. Findings of the current study indicated that the hydro-alcoholic extract of NS improved the LPS-induced learning and memory impairments induced by LPS in rats by improving hippocampal cytokine levels and brain tissues oxidative damage.

Feeding Vitamin C during Neonatal and Juvenile Growth Improves Learning and Memory of Rats

We investigated the effects of feeding vitamin C (Vit C) during neonatal and juvenile growth on learning and memory of rats. Rats after delivery were randomly divided into four groups and treated. Group 1, control group, received normal drinking water. Groups 2-4 received Vit C 10, 100, and 500 mg/kg, respectively, from the first day. After 8 weeks, 10 male offspring of each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA) tests. Finally, the brains were removed for biochemical measurement. In MWM, 10-500 mg/kg Vit C reduced the latency and traveled distance and increased time spent in the target quadrant. In PA, 10 and 100 mg/kg of Vit C increased the latency; 10-500 mg/kg of Vit C decreased the malondialdehyde (MDA) in the brain tissues and increased thiol and catalase (CAT) activity compared to the control group. We showed that feeding rats Vit C during neonatal and juvenile growth has positive effects on learning and memory.

Angiotensin receptor blocker, losartan ameliorates neuroinflammation and behavioral consequences of lipopolysaccharide injection

AIMS

Neuroinflammation has a critical role in brain diseases. Angiotensin II (Ang II) is an important player in inflammation via stimulating of Ang II type 1 receptor (AT1R). In this study, the effects of losartan, an Ang II receptor blocker, on the brain inflammation, oxidative stress and behavioral consequences of lipopolysaccharide (LPS) injection were investigated.

MAIN METHODS

Rats were intraperitoneally (i.p.) injected with 1 or 3 mg/kg losartan or saline for 24 continuous days. At the day 4 of the experiment, rats received a single i.p. injection of 1 mg/kg LPS or saline and two weeks later they received the second LPS challenge which they were administrated with 0.5 mg/kg LPS or saline for 7 continuous days. At the 72 h after the last treatment, the behavioral tests were conducted. The brains were removed for the biochemical analyses.

KEY FINDINGS

LPS injection increased IL (interleukin)-6, malondialdehyde (MDA) and nitric oxide (NO) metabolites and reduced thiol content and activities of catalase (CAT) and superoxide dismutase (SOD) in the cortex and hippocampus. Moreover, LPS injection impaired fear memory in the PA (passive avoidance), induced anhedonia in the SPT (sucrose preference test) and increased immobility time in the FST (force swimming test). Pretreatment with 3 mg/kg losartan decreased the brain IL-6, MDA and NO metabolites while, increased the anti-oxidant parameters and improved the performances of rats in the PA, SPT and FST.

SIGNIFICANCE

The results indicated that systemic inflammation had deleterious long-lasting consequences on brain, which were reversed by pretreatment with losartan.

The effects of vitamin E on brain derived neurotrophic factor, tissues oxidative damage and learning and memory of juvenile hypothyroid rats

The effects of vitamin E (Vit E) on brain derived neurotrophic factor (BDNF) and brain tissues oxidative damage as well as on learning and memory impairments in juvenile hypothyroid rats were examined. The rats were grouped as: (1) Control; (2) Propylthiouracil (PTU); (3) PTU-Vit E and (4) Vit E. PTU was added to their drinking water (0.05%) during 6 weeks. Vit E (20 mg/kg) was daily injected (IP). Morris water maze (MWM) and passive avoidance (PA) were carried out. The animals were deeply anesthetized and the brain tissues were removed for biochemical measurements. PTU increased the escape latency and traveled path in MWM (P < 0.001). It also shortened the latency to enter the dark compartment of PA as well as the time spent in the target quadrant in probe trial of MWM (P < 0.01-P < 0.001). All the effects of PTU were reversed by Vit E (P < 0.01-P < 0.001). PTU administration attenuated thiol and BDNF content as well as the activities of superoxide dismutase (SOD) and catalase (CAT) in the brain tissues while increased molondialdehyde (MDA). Moreover, Vit E improved BDNF, thiol, SOD and CAT while diminished MDA. The results of the present study showed that Vit E improved BDNF and prevented from brain tissues oxidative damage as well as learning and memory impairments in juvenile hypothyroid rats.

Pistacia lentiscus oil attenuates memory dysfunction and decreases levels of biomarkers of oxidative stress induced by lipopolysaccharide in rats

Pistacia lentiscus L. is a well-known medicinal plant that has been used for its antioxidant, anti-inflammatory, neuroprotective, and hepatoprotective effects. However, the neuroprotective effect of Pistacia lentiscus oil (PLo) of has not been reported. The present study was designed to examine the neuroprotective and hepatoprotective effects of PLo aigainst lipopolysaccharide (LPS)-induced memory impairment and oxidative damage in rats. Twenty-four adult male Wistar rats were equally divided into three groups. The first group was kept as a control. In the second group, LPS was given at the single dose of 1 mg/kg intraperitoneally (i.p.). In the third group, PLo (3.3 mL/kg; per orally (p.o.)) was administered daily for 15 days, and challenged with LPS (1 mg/kg; i.p. injection two h before behavioral test). Thereafter, memory was assessed using spatial object recognition test. Cholinesterase activity and oxidative stress response were estimated in brain tissues and liver. PLo attenuated LPS-induced memory impairment in spatial object recognition test (p < 0.05). LPS treatment caused significant oxidative damage via induction of lipid peroxidation and reductions antioxidant defense system potency in the brain tissue and liver. Moreover, LPS increased brain activity of acetylcholinesterase and butyrylcholinesterase activity in the liver. The present results suggest that the beneficial effects of PLo on memory impairment of LPS-treated rats may be due to its protective effects against oxidative stress damage presumably via its antioxidant property.

Protective effect against brain tissues oxidative damage as a possible mechanism for beneficial effects of L-arginine on lipopolysaccharide induced memory impairment in rats

L-Arginine (LA) and nitric oxide (NO) have been suggested to have some effects on learning, memory, brain tissues oxidative damage, and neuroinflammation. In this study, protective effect against brain tissues oxidative damage as a possible mechanism for beneficial effects of LA on lipopolysaccharide (LPS) induced memory impairment was investigated. The rats were grouped into and treated by (1) control (saline), (2) LPS (1 mg/kg, IP), (3) LA (200 mg/kg) - LPS (4) LA. In passive avoidance (PA) test, LPS administration shortened the latency to enter the dark compartment in LPS group compared to control (p < .001) which was accompanied with a high level of malondialdehyde (MDA) and NO metabolite concentrations in the hippocampal tissues (p < .001and p < .05, respectively). Pretreatment with LA prolonged the latency in LA-LPS group compared with LPS group (p < .01-.001) and re-stored MDA and NO metabolites in the hippocampal tissues (p < .05). LPS also reduced superoxide dismutase (SOD) and catalase (CAT) activities and thiol content in the hippocampal tissues in LPS group compared to control (p < .05 and p < .001, respectively) which improved by LA when it was administered before LPS in LA-LPS group (p < .05 and p < .001). Finally, the serum TNFα level of LPS group was higher than the control (p < .01) while, in LA-LPS group it was lower than LPS group (p < .01). It seems that the beneficial effects of LA on memory impairment of LPS-treated rats may be due to its protective effects against brain tissues oxidative damage.

Impact of sex steroids and reproductive stage on sleep-dependent memory consolidation in women

Age and sex are two of the three major risk factors for Alzheimer's disease (ApoE-e4 allele is the third), with women having a twofold greater risk for Alzheimer's disease after the age of 75 years. Sex differences have been shown across a wide range of cognitive skills in young and older adults, and evidence supports a role for sex steroids, especially estradiol, in protecting against the development of cognitive decline in women. Sleep may also be a protective factor against age-related cognitive decline, since specific electrophysiological sleep events (e.g. sleep spindle/slow oscillation coupling) are critical for offline memory consolidation. Furthermore, studies in young women have shown fluctuations in sleep events and sleep-dependent memory consolidation during different phases of the menstrual cycle that are associated with the levels of sex steroids. An under-appreciated possibility is that there may be an important interaction between these two protective factors (sex steroids and sleep) that may play a role in daily fluctuations in cognitive processing, in particular memory, across a woman's lifespan. Here, we summarize the current knowledge of sex steroid-dependent influences on sleep and cognition across the lifespan in women, with special emphasis on sleep-dependent memory processing. We further indicate gaps in knowledge that require further experimental examination in order to fully appreciate the complex and changing landscape of sex steroids and cognition. Lastly, we propose a series of testable predictions for how sex steroids impact sleep events and sleep-dependent cognition across the three major reproductive stages in women (reproductive years, menopause transition, and post-menopause).

The effect of Zataria multiflora on pulmonary function tests, hematological and oxidant/antioxidant parameters in sulfur mustard exposed veterans, a randomized doubled-blind clinical trial

BACKGROUND

Sulfur mustard is an alkylating agent which cause to short and long term incapacitations on various organs including lung. There is no definite treatment for lung disorders induced by SM exposure. In the present study, the preventive effect of Zataria multiflora (Z. multiflora) on hematological parameters, oxidant/antioxidant markers and pulmonary function tests (PFT) in veterans, 27-30 years after exposed to SM were studied.

MATERIALS AND METHODS

Forty seven veterans allocated to three groups included: placebo group (P) and two groups treated with 5 and 10 mg/kg/day of Z. multiflora (Zat 5 and Zat 10). Drugs were prescribed in a double-blind manner for two months. Total and different WBC, hematological indices, oxidant/antioxidant markers and PFT values included; force vital capacity (FVC) and peak expiratory flow (PEF) were assessed at the beginning (step 0), one and two month (step I and II, respectively) after starting treatment.

RESULTS

Total and different white blood cell in Zat 5 and 10 mg/kg treated groups in Step I and II were significantly decreased compared to Step 0 (p < 0.05 to p < 0.001). The levels of thiol, superoxide dismutase (SOD) and catalase (CAT) in Zat 5 and 10 mg/kg treated groups in step I and II were significantly increased (p < 0.05 to p < 0.001) but the level of malondialdehyde (MDA) significantly decreased in two treatment groups compared to Step 0 (p < 0.05 and p < 0.001 respectively). FVC and PEF values were significant increase in Zat 5 and 10 mg/kg treated groups in step I and II compared to step 0 (p < 0.05 to p < 0.001). Furthermore, FVC and PEF values in Zat 5 mg/kg were also increased in step II compared to step I (p < 0.01 for both). The percentage improvement of total and differential WBC, oxidant/antioxidant markers, FVC and PEF values during two moth treatment period significantly improved in the treated groups compared to the placebo group.

CONCLUSION

Z. multiflora reduces inflammatory cells and oxidant biomarkers, while increase antioxidant biomarkers and improved PFT tests in SM exposed patients in a two moth treatment period.

Protective effects of estrogen against cardiovascular disease mediated via oxidative stress in the brain

During their reproductive years women produce significant levels of estrogens, predominantly in the form of estradiol, that are thought to play an important role in cardioprotection. Mechanisms underlying this action include both estrogen-mediated changes in gene expression, and post-transcriptional activation of protein signaling cascades in the heart and in neural centers controlling cardiovascular function, in particular, in the brainstem. There, specific neurons, especially those of the bulbar region play an important role in the neuronal control of the cardiovascular system because they control the outflow of sympathetic activity and parasympathetic activity as well as the reception of chemical and mechanical signals. In the present review, we discuss how estrogens exert their cardioprotective effect in part by modulating the actions of internally generated products of cellular oxidation such as reactive oxygen species (ROS) in brain stem neurons. The significance of this review is in integrating the literature of oxidative damage in the brain with the literature of neuroprotection by estrogen in order to better understand both the benefits and limitations of using this hormone to prevent cardiovascular disease.

The effects of captopril on lipopolysaccharide induced learning and memory impairments and the brain cytokine levels and oxidative damage in rats

AIM

Renin-angiotensin system has a role in inflammation and also involves in learning and memory. In the present study, the effects of captopril on lipopolysaccharide (LPS) induced learning and memory impairments, hippocampal cytokine levels and brain tissues oxidative damage was investigated.

MATERIALS AND METHODS

The rats were divided and treated : [1] saline (Control), [2] LPS (1mg/kg), [3-5] 10, 50 or 100mg/kg captopril 30min before LPS. The treatment was started since six days before the behavioral experiments and continued during the behavioral tests (LPS injection two h before each behavioral experiment).

RESULTS

Administration of LPS prolonged the escape latency and traveled path to find the platform in Morris water maze (MWM) test (P<0.01-P<0.001) while, shortened the latency to enter the dark compartment in passive avoidance (PA) test (P<0.001). Pretreatment by all doses of captopril improved performances of the rats in MWM (P<0.05-P<0.001) and also prolonged the latency to enter the dark in PA test (P<0.001). LPS also increased IL-6, TNF-α, malondialdehyde (MDA) and nitric oxide(NO) metabolites in the hippocampal tissues (P<0.05-P<0.001) which were prevented by captopril (P<0.05-P<0.001). The thiol, superoxide dismutase(SOD) and catalase(CAT) in the hippocampus of LPS group were lower than the control (P<0.001) while, they were enhanced when the aniamls were pretraeted by captopril (P<0.01-P<0.001).

CONCLUSION

The results of present study showed that captopril improved the LPS-induced learning and memory impairments in rats which were accompanied with attenuating hippocampal cytokine levels and improving the brain tissues oxidative damage criteria.

Cognitive Functions, Concentration of Endogenous Estradiol, Estrogen Receptor α (ERα) Polymorphism in Postmenopausal Women

BACKGROUND The goal of this study was to investigate the relationship between cognitive functions and the level of endogenous estradiol in postmenopausal women, according to which estrogen receptor α (ERα) polymorphism the woman carries. MATERIAL AND METHODS The study group consisted of 210 women. The inclusion criteria were: minimum 2 years after the last menstruation, FSH concentration 30 U/ml, and no dementia signs on Montreal Cognitive Assessment (MoCA). A computerized battery of Central Nervous System Vital Signs (CNS VS) test was used to diagnose cognitive functions. Genotyping of the ERa polymorphism was performed using a polymerase chain reaction and restriction enzymes (PCR-RFLP). Blood plasma was tested for FSH and estradiol (E2). Statistical analysis was performed using STATISTICA software. RESULTS A relationship was confirmed between standard scores for 3 cognitive functions: general memory, verbal memory, and processing speed, and the XbaI polymorphism in the women in the study. In the group of women with genotype TT PvuII, significant positive relationships were observed between the concentration of E2 and the standard scores of 3 cognitive functions: general memory, verbal memory, and processing speed. In the group of women with genotype TC PvuII, significant negative correlations were found between the concentration of E2 and the standard scores of 4 cognitive functions: NCI, general memory, verbal memory, and processing speed. CONCLUSIONS ERα polymorphism exerted an effect on the interaction between the concentration of estradiol and the results for cognitive functions. The concentration of estradiol did not depend on Xba1 and PvuII polymorphisms. The results for cognitive functions depended on which Xba1 polymorphism the woman carried.

Inducible nitric oxide inhibitor aminoguanidine, ameliorates deleterious effects of lipopolysaccharide on memory and long term potentiation in rat

AIM

An interaction between nitric oxide (NO) and neuro-inflammation has been considered to modulate learning and memory. In the present study, the effect of an inducible NO synthase (iNOS) inhibitor, aminoguanidine (AG) on lipopolysaccharide (LPS)-induced memory impairment was evaluated.

MATERIALS AND METHODS

The rats were divided and treated: Control (Saline), LPS, AG - LPS and AG, before behavioral and electrophysiological experiments.

RESULTS

The escape latency in Morris water maze (MWM) test and the latency to enter the dark compartment in Passive avoidance (PA) test in LPS group were significantly higher than in control (P<0.001) whereas, in AG-LPS group they were shorter than LPS group (P<0.001). The amplitude and slope of field excitatory post synaptic potential (fEPSP) decreased in LPS group compared to control group (P<0.05 and P<0.01) whereas, in AG-LPS group they were higher than LPS group (P<0.05). Malondialdehyde (MDA) and NO metabolites concentrations in the hippocampus and serum TNFα level of LPS group were higher than control group (P<0.001, P<0.05 and 0.01 respectively) while, in AG- LPS group they were lower than LPS group (P<0.001and P<0.01 respectively). The thiol content and the activities of superoxide dismutase (SOD) and catalase (CAT) in the hippocampus of LPS group reduced compared to control group (P<0.001 and P<0.05 respectively) while, in AG - LPS group they enhanced compared to LPS (P<0.001 and P<0.05 respectively).

CONCLUSION

It is suggested that increased NO has a role in LPS-induced learning and LTP impairments and the brain tissues oxidative damage which are preventable by iNOS inhibitor aminoguanidine.

Neuronal nitric oxide synthase has a role in the detrimental effects of lipopolysaccharide on spatial memory and synaptic plasticity in rats

BACKGROUND

The role of neuronal nitric oxide synthase (nNOS) in lipopolysaccharide (LPS)-induced memory and synaptic plasticity impairment was investigated.

METHODS

The rats were divided and treated as follows: (1) control (saline), (2) LPS, (3) 7NI (7-nitroindazole as a nNOS inhibitor)-LPS and (4) 7NI.

RESULTS

In a Morris water maze, the LPS group took a longer amount of time and traveled a greater distance to reach the platform, this was prevented by 7NI. Malondialdehyde (MDA) and nitric oxide (NO) metabolites in the hippocampus of the LPS group were higher while the total thiol, superoxide dismutase and catalase were lower than that of the controlled specimen. Pre-treatment using 7NI prevented the changes in the biochemical criteria. The slope and amplitude of the field excitatory post-synaptic potential (fEPSP) in the LPS group decreased, whereas in 7NI-LPS group they increased.

CONCLUSION

It is suggested that inhibition of nNOS by 7NI improves the deleterious effects of LPS by reducing NO metabolites and the brain tissues oxidative damage.

Feeding of Nigella sativa during neonatal and juvenile growth improves learning and memory of rats

The positive roles of antioxidants on brain development and learning and memory have been suggested. Nigella sativa (NS) has been suggested to have antioxidant and neuroprotective effects. This study was done to investigate the effects of feeding by the hydro-alcoholic extract of NS during neonatal and juvenile growth on learning and memory of rats. The pregnant rats were kept in separate cages. After delivery, they were randomly divided into four Groups including: (1) control; (2) NS 100 mg/kg (NS 100); (3) NS 200 mg/kg (NS 200); and (4) NS 400 mg/kg (NS 400). Rats in the control group (Group 1) received normal drinking water, whereas Groups 2, 3, and 4 received the same drinking water supplemented with the hydro-alcoholic extract of NS (100 mg/kg, 200 mg/kg, and 400 mg/kg, respectively) from the 1st day after birth through the first 8 weeks of life. After 8 weeks, 10 male offspring from each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA) test. Finally, the brains were removed and total thiol groups and malondialdehyde (MDA) concentrations were determined. In the MWM, treatment by 400 mg/kg extract reduced both the time latency and the distance traveled to reach the platform compared to the control group (p < 0.05-p < 0.01). Both 200 mg/kg and 400 mg/kg of the extract increased the time spent in the target quadrant (p < 0.05-p < 0.01). In the PA test, the treatment of the animals by 200 mg/kg and 400 mg/kg of NS extract significantly increased the time latency for entering the dark compartment (p < 0.05-p < 0.001). Pretreatment of the animals with 400 mg/kg of NS extract decreased the MDA concentration in hippocampal tissues whereas it increased the thiol content compared to the control group (p < 0.001). These results allow us to propose that feeding of the rats by the hydro-alcoholic extract of NS during neonatal and juvenile growth has positive effects on learning and memory. The effects might be due to the antioxidant effects.

Estrogens, inflammation and cognition

The effects of estrogens are pleiotropic, affecting multiple bodily systems. Changes from the body's natural fluctuating levels of estrogens, through surgical removal of the ovaries, natural menopause, or the administration of exogenous estrogens to menopausal women have been independently linked to an altered immune profile, and changes to cognitive processes. Here, we propose that inflammation may mediate the relationship between low levels of estrogens and cognitive decline. In order to determine what is known about this connection, we review the literature on the cognitive effects of decreased estrogens due to oophorectomy or natural menopause, decreased estrogens' role on inflammation--both peripherally and in the brain--and the relationship between inflammation and cognition. While this review demonstrates that much is unknown about the intersection between estrogens, cognition, inflammation, we propose that there is an important interaction between these literatures.

The effects of Nigella sativa on sickness behavior induced by lipopolysaccharide in male Wistar rats

OBJECTIVE

Neuroimmune factors contribute on the pathogenesis of sickness behaviors. Nigella sativa (NS) has anti-inflammatory, anti-anxiety and anti-depressive effects. In the present study, the effect of NS hydro-alcoholic extract on sickness behavior induced by lipopolysaccharide (LPS) was investigated.

MATERIALS AND METHODS

The rats were divided into five groups (n=10 in each): (1) control (saline), (2) LPS (1 mg/kg, administered two hours before behavioral tests), (3-5) LPS-Nigella sativa 100 , 200 and 400 mg/kg (LPS-NS 100, LPS-NS 200 and LPS-NS 400, respectively). Open- field (OF), elevated plus maze (EPM) and forced swimming test (FST) were performed.

RESULTS

In OF, LPS reduced the peripheral crossing, peripheral distance, total crossing and total distance compared to control (p<0.01- p<0.001). The central crossing, central distance and central time in LPS-NS 100, LPS-NS200 and LPS-NS 400 groups were higher than LPS (p<0.01- p<0.001). In EPM, LPS decreased the open arm entries, open arm time and closed arm entries while increased the closed time compared to control (p<0.001). Pretreatment by NS extract reversed the effects of LPS (p<0.05- p<0.001). In FST, LPS increased the immobility time while, decreased the climbing and active times compared to control (p<0.05- p<0.001). In LPS-NS 100, LPS-NS 200 and LPS-NS 400 groups the immobility time was less while, the active and climbing times were more than those of LPS (p<0.05- p<0.001).

CONCLUSION

The results of the present study showed that the hydro-alcoholic extract of NS reduced the LPS-induced sickness behaviors in rats. Further investigations are required for better understanding the responsible compound (s) and the underlying mechanism(s).

The effects of tamoxifen on spatial and nonspatial learning and memory impairments induced by scopolamine and the brain tissues oxidative damage in ovariectomized rats

Background:

Modulatory effects of tamoxifen (TAM) on the central nervous system have been reported. The effects of TAM on spatial and nonspatial learning and memory impairments induced by scopolamine and the brain tissues oxidative damage was investigated.

Materials and Methods:

The ovariectomized (OVX) rats were divided and treated: (1) Control (saline), (2) scopolamine (Sco; 2 mg/kg, 30 min before behavioral tests), (3–5) Sco-TAM 1, Sco-TAM 3 and Sco-TAM 10. TAM (1, 3 or 10 mg/kg; i.p.) was daily administered for 6 weeks.

Results:

In Morris water maze (MWM), both the latency and traveled distance in the Sco-group were higher than control (P < 0.001) while, in the Sco-TAM 10 group it was lower than Sco-group (P < 0.05). In passive avoidance test, the latency to enter the dark compartment was higher than control (P < 0.05 – P < 0.01). Pretreatment by all three doses of TAM prolonged the latency to enter the dark compartment compared to Sco-group (P < 0.05 – P < 0.001). The brain tissues malondialdehyde (MDA) concentration was increased while, superoxide dismutase activity (SOD) decreased in the Sco-group compared to control (P < 0.05 – P < 0.01). Pretreatment by TAM lowered the concentration of MDA while, increased SOD compared to Sco-group (P < 0.05 – P < 0.001).

Conclusions:

It is suggested that TAM prevents spatial and nonspatial learning and memory impairments induced by scopolamine in OVX rats. The possible mechanism(s) might at least in part be due to protection against the brain tissues oxidative damage.

Lipopolysaccharide-induced memory impairment in rats is preventable using 7-nitroindazole

Inflammation and oxidative stress have important roles in memory impairment. The effect of 7-nitroindazole (7NI) on lipopolysaccharide (LPS)-induced memory impairment was investigated. Rats were used, divided into four groups that were treated as follows: (1) control (saline); (2) LPS; (3) 7NI-LPS; and (4) 7NI before passive avoidance (PA). In the LPS group, the latency for entering the dark compartment was shorter than in the controls (p < 0.01 and p < 0.001); while in the 7NI-LPS group, it was longer than in the LPS group (p < 0.01 and p < 0.001). Malondialdehyde (MDA) and nitric oxide (NO) metabolite concentrations in the brain tissues of the LPS group were higher than in the controls (p < 0.001 and p < 0.05); while in the 7NI-LPS group, they were lower than in the LPS group (p < 0.001 and p < 0.05, respectively). The thiol content in the brain of the LPS group was lower than in the controls (p < 0.001); while in the 7NI-LPS group, it was higher than in the LPS group (p < 0.001). It is suggested that brain tissue oxidative damage and NO elevation have a role in the deleterious effects of LPS on memory retention that are preventable using 7NI.

Effects of hydroalcoholic extract of Coriandrum sativum on oxidative damage in pentylenetetrazole-induced seizures in rats

BACKGROUND

An important role for oxidative stress, as a consequence of epileptic seizures, has been suggested. Coriandrum sativum has been shown that have antioxidant effects. Central nervous system depressant effects of C. sativum have also been reported. In this study, the effects of hydroalcoholic extract of aerial parts of the plants on brain tissues oxidative damages following seizures induced by pentylenetetrazole (PTZ) was investigated in rats.

METHODS

The rats were divided into five groups and treated: (1) Control (saline), (2) PTZ (90 mg/kg, i.p.), (3-5) three doses (100, 500 and 1000 mg/kg of C. sativum extract (CSE) before PTZ. Latencies to the first minimal clonic seizures (MCS) and the first generalized tonic-clonic seizures (GTCS) were recorded. The cortical and hippocampal tissues were then removed for biochemical measurements.

RESULTS

The extract significantly increased the MCS and GTCS latencies (P < 0.01, P < 0.001) following PTZ-induced seizures. The malondialdehyde (MDA) levels in both cortical and hippocampal tissues of PTZ group were significantly higher than those of the control animals (P < 0.001). Pretreatment with the extract prevented elevation of the MDA levels (P < 0.010-P < 0.001). Following PTZ administration, a significant reduction in total thiol groups was observed in both cortical and hippocampal tissues (P < 0.050). Pre-treatment with the 500 mg/kg of the extract caused a significant prevention of decreased in total thiol concentration in the cortical tissues (P < 0.010).

CONCLUSION

The present study showed that the hydroalcoholic extract of the aerial parts of C. sativum possess significant antioxidant and anticonvulsant activities.

Tamoxifen antagonizes the effects of ovarian hormones to induce anxiety and depression-like behavior in rats

The effects of tamoxifen (TAM) on anxiety and depression-like behavior in ovariectomized (OVX) and naïve female rats were investigated. The animals were divided into Sham-TAM, OVX-TAM, Sham and OVX groups. Tamoxifen (1 mg/kg) was administered for 4 weeks. In the forced swimming test, the immobility times in the OVX and Sham-TAM groups were higher than in the Sham group. In the open field, the numbers of central crossings in the OVX and Sham-TAM groups were lower than the number in the Sham group, and the number of peripheral crossings in the OVX group was lower than the number in the Sham group. In the elevated plus maze, the numbers of entries to the open arm among the animals in the Sham-TAM and OVX groups were lower than the number in the Sham group, while the number of entries to the open arm in the OVX-TAM group was higher than the number in the OVX group. It was shown that deletion of ovarian hormones induced anxiety and depression-like behavior. Administration of tamoxifen in naïve rats led to anxiety and depression-like behavior that was comparable with the effects of ovarian hormone deletion. It can be suggested that tamoxifen antagonizes the effects of ovarian hormones. It also seems that tamoxifen has anxiolytic effects on ovariectomized rats.

Deletion of ovarian hormones induces a sickness behavior in rats comparable to the effect of lipopolysaccharide

Neuroimmune factors have been proposed as the contributors to the pathogenesis of sickness behaviors. The effects of female gonadal hormones on both neuroinflammation and depression have also been well considered. In the present study, the capability of deletion of ovarian hormones to induce sickness-like behaviors in rats was compared with the effect lipopolysaccharide (LPS). The groups were including Sham, OVX, Sham-LPS, and OVX-LPS. The Sham-LPS and OVX-LPS groups were treated with LPS (250 μg/kg) two hours before conducting the behavioral tests. In the forced swimming (FST), the immobility times in both OVX and Sham-LPS groups were higher than that of Sham (P < 0.001). In open-field (OP) test, the central crossing number by OVX and Sham-LPS groups were lower than Sham (P < 0.001) while there were no significant differences between OVX-LPS and OVX groups. In elevated plus maze (EPM), the percent of entries to the open arm by both OVX and Sham-LPS groups was lower than that of Sham group (P < 0.001). The results of present study showed that deletion of ovarian hormones induced sickness behaviors in rats which were comparable to the effects of LPS. Moreover, further investigations are required in order to better understand the mechanism(s) involved.