Metformin improves memory via AMPK/mTOR-dependent route in a rat model of Alzheimer's disease

Objectives

Metformin, as an insulin sensitizer, is a familiar antidiabetic drug. Increasing evidence points to metformin's protective effects against Alzheimer's disease (AD). However, the mechanism is not well understood. The present study evaluated whether inhibiting AMPK and activating mTOR could stop metformin from improving memory in rats with streptozotocin (STZ) -induced Alzheimer's disease.

Materials and Methods

Twelve-week-old Wistar rats, were injected 3 mg/kg STZ intracerebroventricularly on days 1 and 3 to develop the animal model. Metformin was applied orally at 100 mg/kg (17 days). Forty-five min before the retrieval phase, dorsomorphin (DM; AMPK inhibitor, 2 M) and MHY (mTOR activator, 0.1 M) were administered. Morris Water Maze (MWM) and shuttle box were utilized to measure spatial and passive avoidance memory, respectively. Congo red staining was used to identify cortical amyloid deposition.

Results

The findings exhibited a considerable enhancement in spatial learning and memory in the metformin treatment group (P≤0.05). Injection of DM and MHY alone could not significantly change MWM and passive avoidance. Additionally, co-administration of DM and MHY increased escape latency (P≤0.001) and reduced the total time spent in the target quadrant (TTS) (P≤0.05) compared to the STZ+MET group during retrieval of MWM. Also, co-injection of DM and MHY increased step-through latency (STL) and decreased time spent in the dark compartment (TDC) compared to the STZ+MET group (P≤0.001).

Conclusion

Metformin appears to have a therapeutic impact by activating AMPK and inactivating mTOR. As a result, it could be used as an Alzheimer's treatment strategy.

Therapeutic Effects Of Combined and Chronic Treatment of Tat-GluA23y and D-Serine on Cognitive Dysfunction in Postmenopausal Rats

BACKGROUND

The incidence of Alzheimer's disease (AD) in female gender compared with male has been addressed as a health concern, particularly in menopausal age. We here hypothesized that co-administration of NMDARs agonist (D-serine) and AMPARs endocytosis inhibitor (Tat-GluA23y) might be a potential target for alleviating memory impairment in sporadic Alzheimer model of rats.

METHODS

Forty-eight female Wistar rats weighing 200-220 randomly divided into six groups. One month later, ovariectomized rats underwent stereotaxic surgery and were cannulated into the brain lateral ventricles. Streptozotocin was injected (3 mg/kg), then animals received the related treatments until the day 51, which experienced acquisition of spatial memory in Morris Water Maze test. Finally, the level of phosphorylated cAMP response element binding protein (CREB) in the hippocampus was measured by Western blotting.

RESULTS

Co-administration of D-serine and GluA23y significantly enhanced the acquisition and retrieval of impaired spatial memory in ovariectomized rats with AD (p < .001). Compared to Glu-A 23, D-serine caused more improvement in the mentioned parameters above, however, these values for both groups were still significantly different from the control group (P < .05).

CONCLUSION

Simultaneous treatment with D-serine and GluA23y synergistically improved STZ induced spatial memory impairment in OVX rat, probably partly via increase in phosphorylated CREB protein.

Concurrent high-intensity interval training and probiotic supplementation improve associative memory via increase in insulin sensitivity in ovariectomized rats

OBJECTIVES

Metabolic syndrome (MetS) is a serious concern among postmenopausal women which predisposes them to cardiovascular and cognitive disorders. Healthful diet and exercise training have been essential strategies to prevent the progress of MetS. The aim of this study was to evaluate the effect of supplementation with a native potential probiotic and high-intensity interval training (HIIT) for 8 weeks on retention of associative memory in rats with ovariectomy- induced metabolic syndrome.

METHOD

Thirty-two female ovariectomized Wistar rats were divided into four groups (n = 8/group): Control (OVX + Veh), exercise (OVX + Exe), probiotic (OVX + Pro), exercise with probiotic (OVX + Exe + Pro). One sham surgery group was included as a control group. Animals received 8 weeks interventions, and then were tested in a step through passive avoidance learning and memory paradigm, to assess long term memory. Then serum levels of adiponectin, insulin and glucose were measured by ELISA and colorimetry respectively. Data were analyzed by Kruskal-Wallis, Mann-Whitney and also One-way analysis of variance (ANOVA).

RESULTS

Eight weeks of HIIT and probiotic supplementation caused an increase in step through latency and shortening of total time spent in the dark compartment in OVX + Exe + Pro group compared with OVX + Veh group. Also significant increase in serum adiponectin levels, in parallel with a reduction in glucose, insulin and HOMA-IR were achieved by the group of OVX + Exe + Pro.

CONCLUSION

The present study indicates that HIIT combined with probiotics supplementation for 8 weeks effectively improves associative memory in MetS model of rats partly via improving insulin sensitivity and adiponectin level.

Myocardial angiogenesis induced by concurrent vitamin D supplementation and aerobic-resistance training is mediated by inhibiting miRNA-15a, and miRNA-146a and upregulating VEGF/PI3K/eNOS signaling pathway

This study aimed to investigate the effects of co-treatment of aerobic-resistance training (ART), vitamin D₃ (VD₃) on cardiovascular function considering the involvement of microRNA-15a and microRNA-146a, vascular endothelial growth factor (VEGF), phosphatidylinositol-3 kinase (PI3K), and endothelial nitric oxide synthase (eNOS) after myocardial infarction (MI) in rats. To induce MI, male Wistar rats subcutaneously received isoproterenol for 2 days, then MI was confirmed by echocardiography. MI rats were divided into six groups (n = 8/group). MI + VD₃, MI + sesame oil (Veh), MI + ART, MI + VD₃ + ART, and MI + Veh + ART, and received the related treatments for 8 weeks. Exercise tests, echocardiography, real-time quantitative polymerase chain reaction (qRT-PCR), western blotting, and histological staining were performed after the end of treatments. The highest ejection fraction (EF%), fractional shortening (FS%), exercise capacity (EC), and maximal load test (MLT) amounts were observed in the groups treated with VD₃, ART, and VD₃ + ART (P < 0.05). These were accompanied by a significantly increased angiogenesis post-MI. Furthermore, the levels of circulating microRNA-15a and microRNA-146a were significantly decreased in these groups compared to MI rats that were together with a significant upregulation of cardiac VEGF, PI3K, and eNOS expression. Overall, the best results were observed in the group treated with VD₃ + ART. Concurrent VD₃ supplementation and ART attenuated microRNA-15a and microRNA-146a and induced angiogenesis via VEGF/PI3K/eNOS axis. This data demonstrate that concurrent VD₃ supplementation and ART is a more efficient strategy than monotherapy to improve cardiac function post-MI.

Metabotropic Effect of Probiotic Supplementation and High-Intensity Interval Training in Menopause-Induced Metabolic Syndrome in Rats

OBJECTIVES

This study aimed to investigate the interactive effect of supplementation with a native potential probiotic lactobacillus and 8-week high-intensity interval training (HIIT) on insulin resistance and dyslipidemia in a menopause-induced metabolic syndrome.

METHODS

A total of 40 ovariectomized (OVX) Wistar rats were divided into five groups: control (OVX + Vehicle), exercise (EXE) (OVX + Exe), probiotic (Prob) (OVX + Prob), exercise and probiotic (OVX + Exe + Prob), and sham surgery. After the end of the treatment interventions, body weight, body mass index (BMI), waist circumference (WC), visceral fat, and serum concentrations of glucose, insulin, lipid profile, and adiponectin were measured using colorimetric analysis and enzyme-linked immunosorbent assay, respectively.

RESULTS

Data revealed a significant decrease in weight, waist circumference , visceral fat, BMI, and levels of glucose, insulin, homeostasis model assessment of insulin resistance, triacylglyceride, total cholesterol, and low-density lipoprotein (LDL), but an increase in high-density lipoprotein and adiponectin levels (P = 0.001), in OVX + Exe + Prob compared with the OVX + Vehicle group.

CONCLUSIONS

The present study indicates that native probiotic lactobacillus combined with HIIT effectively reduces body weight, visceral fat, and levels of LDL, glucose, and insulin and increases adiponectin level, although exercise contributes more to fat reduction and probiotics to insulin resistance.

Protective effect of miR-34c antagomir against STZ-induced memory impairment by targeting mTOR and PSD-95 in the hippocampus of rats

After long times of ongoing research, still there is no appropriate cure for Alzheimer's disease (AD). Recently, epigenetic alterations, particularly miRNA, have gotten attention in AD research. Among various miRNA, miR-34c has been addressed to be elevated in the brain of AD patients, however, its exact role and downstream mechanisms have not been elucidated yet. This study aimed to investigate the therapeutic potential of miR-34c antagomir on cognitive dysfunction induced by streptozocin (STZ), considering postsynaptic density protein 95 (PSD-95) and mammalian target of rapamycin expression (mTOR). Forty rats were cannulated intraventricularly under deep anesthesia using stereotaxic apparatus and divided into five groups: saline + saline, STZ + saline, STZ + miR-34c antagomir, STZ + lipofectamine, and STZ + scrambled, and received the related treatments for two weeks. At the end of the treatments, spatial memory and locomotor activity were assessed by Morris water maze (MWM), and open fields, respectively. Finally, PSD-95 and mTOR levels were measured by quantitative real-time PCR (qPCR) and western blotting on hippocampal samples. Results showed that miR-34c antagomir markedly ameliorated spatial learning and memory deficits induced by STZ, and significantly enhanced PSD-95 and mTOR levels in the hippocampus. In conclusion, miR-34c antagomir may be considered as a promising novel therapeutic target for AD patients.

Effects of inhibiting astrocytes and BET/BRD4 chromatin reader on spatial memory and synaptic proteins in rats with Alzheimer's disease

Communication between astrocytes and neurons has a profound effect on the pathophysiology of Alzheimer's disease (AD). Astrocytes regulate homeostasis and increase synaptic plasticity in physiological situations, however, they become activated during the progression of AD. Whether or not these reactions are supportive or detrimental for the central nervous system have not been understood yet. Considering epigenetic regulation of neuroinflammatory genes by chromatin readers, particularly bromodomain and extraterminal domain (BET) family, here we examined the effect of chronic co-inhibition of astrocytes metabolism (with fluorocitrate) and also BRD4 (with JQ1) on cognition deficit at early stages of AD. Forty adult male Wistar rats underwent stereotaxic cannulation for inducing AD by intrahippocampal injection of Aβ1-42 (4 μg/8 μl/rat). Then animals were divided into five groups of Saline+DMSO, Aβ + saline+DMSO, Aβ + JQ1, Aβ + FC (fluorocitrate), and Aβ + JQ1 + FC and received the related treatments. Two weeks later, spatial memory was recorded by Morris Water Maze (MWM), and the levels of phosphorylated cyclic-AMP response element binding protein (CREB), postsynaptic density 95 (PSD95), synaptophysin (SYP), and tumor necrosis factor-alpha (TNF-α) were measured in the hippocampus by western blotting and RT-qPCR. Administration of JQ1 significantly improved both acquisition and retrieval of spatial memory, which were evident by decreased escape latency and increased total time spent (TTS) in target quadrant, and significant rise in p-CREB, PSD95, and synaptophysin compared with Aβ + saline+DMSO group. In contrast, both groups receiving FC demonstrated memory decline, and reduction in p-CREB, PSD95 and synaptophysin in parallel with increase in TNF-α. Our data indicate that chronic inhibition of BRD4 significantly restores memory impaired by amyloid β partly via CREB signaling and upregulating synaptic proteins of PSD95 and synaptophysin. However, inhibition of astrocytes nullifies the memory-boosting effects of JQ1 and reduces CREB/PSD95/synaptophysin levels in hippocampus.

Exercise Training Improves Memory Performance in Older Adults: A Narrative Review of Evidence and Possible Mechanisms

Exercise, neurotransmitters, growth factors, myokines, and potential effects on the brain.

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Exercise training modulates adipokines dysregulations in metabolic syndrome

Metabolic syndrome (MetS) is a cluster of risk factors for various metabolic diseases, and it is characterized by central obesity, dyslipidemia, hypertension, and insulin resistance. The core component for MetS is adipose tissue, which releases adipokines and influences physical health. Adipokines consist of pro and anti-inflammatory cytokines and contribute to various physiological functions. Generally, a sedentary lifestyle promotes fat accumulation and secretion of pro-inflammatory adipokines. However, regular exercise has been known to exert various beneficial effects on metabolic and cognitive disorders. Although the mechanisms underlying exercise beneficial effects in MetS are not fully understood, changes in energy expenditure, fat accumulation, circulatory level of myokines, and adipokines might be involved. This review article focuses on some of the selected adipokines in MetS, and their responses to exercise training considering possible mechanisms.

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Adipokines are a potential link between visceral fats and complications of MetS.

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Physical inactivity increases pro-inflammatory adipokines.

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Moderate aerobic exercise increases anti-inflammatory adipokines partly via reducing adipose tissue mass.

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Physical exercise-induced myokines might mediate beneficial effects via a cross-talk with adipose tissues.

The Effect of Kaempferol on Autophagy and Nrf-2 Signaling in a Rat Model of Aβ1-42-induced Alzheimer’s Disease

Background: Numerous pieces of evidence support that oxidative stress is a key factor in the pathogenesis of neurodegenerative diseases, like Alzheimer’s Disease (AD). Suppression of oxidative stress is an attractive strategy and flavonoids as potent natural antioxidants are extremely noticeable. Objectives: In this study, the effects of Kaempferol (KMP) were evaluated on passive avoidance memory, hippocampal Nrf-2, and beclin-1 expression in a rat model of Aβ1-42 –induced AD. Materials & Methods: Forty male Wistar rats weighing 200-250 g were divided into five groups (n=8); sham-operated, AD model, and KMP treatment (5, 7.5, 10 mg/kg, i.p. for three weeks). Animals received an intracerebroventricular injection of amyloid-beta (1-42) to establish an AD model. Passive avoidance memory of rats was evaluated using a shuttle box on day 21; Step-Through Latency (STL) and time spent in The Dark Compartment (TDC) were recorded. Then, hippocampus homogenates were used for biochemical and molecular analysis by real-time PCR, western blot, and ELISA. Results: It was found that KMP improved memory evidenced by increased STL (P≤0.05) and decreased TDC (p≤0.01). KMP also increased the levels of Total Antioxidant Capacity (TAC) in the hippocampus of rats (P≤0.05). In addition, KMP enhanced the expression of Nrf-2 mRNA (P≤0.001) and beclin-1 protein in the hippocampus tissues (P≤0.001). Conclusion: Overall, it is suggested that the memory-improving effect of KMP is mediated, at least in part, by enhancing Nrf-2 and TAC. KMP is also able to induce autophagy through the expression of beclin-1.

NMDA and AMPA receptors dysregulation in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative condition characterized by cognitive dysfunction and synaptic failure. The current therapeutic approaches are mainly focused on symptomatic treatment and possess limited effectiveness in addressing the pathophysiology of AD. It is known that neurodegeneration is negatively correlated with synaptic plasticity. This negative correlation highlights glutamatergic neurotransmission via N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors and (AMPA) receptors as a critical mediator of synaptic plasticity. Despite this favorable role, extensive extracellular glutamate concentration induces excitotoxicity and neurodegeneration. NMDA receptors containing GluN2A subunits are located at synaptic sites, implicated in the protective pathways. In comparison, GluN2B containing receptors are located mainly at extrasynaptic sites and increase neuronal vulnerability. AMPA receptors are consistently endocytosed and recycled back to the membrane. An increase in the rate of endocytosis has been implicated as a part of AD pathophysiology through inducing long-term depression (LTD) and synaptic disintegration. In the present review, we focused on the mechanisms of glutamatergic system dysregulation in AD, particularly on its interaction with amyloid-beta. We concluded that assigning a specific role to an individual subtype of either NMDA receptors or AMPA receptors might be an oversimplification as they are not static receptors. Therefore, any imbalance between synaptic and extrasynaptic NMDA receptors and a reduced number of surface AMPA receptors will lead to synaptopathy.

Sex-Independent Cognition Improvement in Response to Kaempferol in the Model of Sporadic Alzheimer's Disease

Alzheimer's disease (AD) is associated with neural oxidative stress and inflammation, and it is assumed to affect more women than men with unknown mechanisms. Kaempferol (KMP) as a potent natural antioxidant has been known to exhibit various biological and pharmacological functions, including antioxidant and anti-inflammatory. We aimed here to evaluate the role of gender difference in response to KMP on the rat model of sporadic AD. Forty-six female and male Wistar rats were divided into six groups of sham, streptozotocin (STZ) + saline (SAL), STZ + KMP. Female rats were ovariectomized, and then all animals received an intracerebroventricular bilateral injection of STZ (3 mg/kg) to induce the AD model. KMP (10 mg/kg) was intraperitoneally administered for 21 consecutive days. Afterward, spatial learning and memory were assessed via the Morris water maze task (MWM). Finally, the hippocampus level of superoxide dismutase (SOD), glutathione, and malondialdehyde were measured using calorimetric kits. Data showed a significant cognition deficit in STZ + SAL compared with the sham. To sum up, we reported that chronic KMP treatment increase significantly improved acquisition and retrieval of spatial memory as evident by longer TTS (total time spent) and short-latency to the platform in MWM. In addition, KMP increased the levels of SOD and glutathione in the hippocampus of rats. Also, KMP decreased hippocampal levels of malondialdehyde in both genders. In conclusion, KMP successfully restores spatial memory impairment independent of gender difference. This memory restoration may at least in part be mediated through boosting the hippocampal level of SOD and glutathione.

Synergistic enhancing-memory effect of D-serine and RU360, a mitochondrial calcium uniporter blocker in rat model of Alzheimer's disease

BACKGROUND

Although Amyloid beta (Aβ) and N - methyl d- aspartate receptors (NMDARs are involved in Ca²⁺ neurotoxicity, the function of mitochondrial calcium uniporter in cognition deficit remain uncertain. Here, we examined the effect of mitochondrial calcium uniporter (MCU) blocker, together with NMDA receptor agonist d-cycloserine (DCS) on memory impairment in a rat model of AD.

METHODS

Forty adult male Wistar rats underwent stereotaxic cannulation for inducing AD by intracerebroventricular (ICV) injection of Aβ_1-42 (5 μg /8 μl/rat). Then animals were divided into 5 groups of: Saline + Saline, Aβ + Saline, Aβ + RU360, Aβ + DCS, Aβ + RU360 + DCS. Two weeks after the treatments, Morris Water Maze (MWM) and step through passive avoidance learning (SPL) were undertaken for evaluating of spatial and associative memories, respectively. Hippocampal level of cyclic-AMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) were measured by western blot and ELISA.

RESULTS

Co - administration of RU360 and DCS significantly improved both acquisition and retrieval of spatial memory as evident by decreased escape latency and increased time spent in the target quadrant (TTS) in MWM, together with increase in step-through latency, but reduced time spent in the dark compartment in SPL. Furthermore, there was a significant rise in the hippocampal level of CREB and BDNF in comparison with Aβ + Saline.

CONCLUSION

The present study supports the idea that co- administration of RU360 and DCS ameliorate memory impairment induced by Aβ _1-42 probably via CREB / BDNF signaling.

Chronic administration of Tat-GluR23Y ameliorates cognitive dysfunction targeting CREB signaling in rats with amyloid beta neurotoxicity

Alzheimer's disease (AD) is behaviorally characterized by memory impairments, and pathologically by amyloid β1-42 (Aβ1-42) plaques and tangles. Aβ binds to excitatory synapses and disrupts their transmission due to dysregulation of the glutamate receptors. Here we hypothesized that chronic inhibition of the endocytosis of AMPA receptors together with GluN2B subunit of NMDA receptors might improve cognition deficit induced by Aβ(1-42) neurotoxicity. Forty male Wistar rats were used in this study and divided into 5 groups: Saline + Saline, Aβ+Saline, Aβ+Ifen (Ifenprodil, 3 nmol /2 weeks), Aβ+GluR23Y (Tat-GluR23Y 3 μmol/kg/2 weeks) and Aβ+Ifen+GluR23Y (same doses and durations). Aβ(1-42) neurotoxicity was induced by intracerebroventricular (ICV) injection of Aβ1-42 (2 μg/μl/side), and then animals received the related treatments for 14 days. Cognitive performance of rats and hippocampal level of cAMP-response element-binding (CREB) were evaluated using Morris Water Maze (MWM), and western blotting respectively. Obtained data from the acquisition trials were analyzed by two way Anova and Student T test. Also one way Analysis of variance (ANOVA) with post hoc Tuckey were used to clarify between groups differences in probe test. The Group receiving Aβ, showed significant cognition deficit (long latency to platform and short total time spent in target quadrant (TTS), parallel with lower level of hippocampal CREB, versus vehicle group. While, Aβ+ GluR23Y exhibited the shortest latency to platform and the longest TTS during the probe test, parallel with the higher hippocampal level of CREB compared with other groups. The present study provides evidence that chronic administration of Tat-GluR23Y; an inhibitor of GluA2-AMPARs endocytosis, successfully restores spatial memory impaired by amyloid beta neurotoxicity targeting CREB signaling pathway.

Acute effects of strength and endurance exercise on serum BDNF and IGF-1 levels in older men

Background

Regarding an important effects of physical exercise on brain function in elders, the aim of this study was to examine the effects of strength and endurance exercise on brain neurobiological factors in older men.

Methods

Thirty older men volunteered to participate in this study and were randomly assigned to strength, endurance and control groups. The subjects in strength group performed two circuits of resistance exercise (6 exercises with 10 repetition of 65–70% of one repetition maximum), while endurance group performed 30 min running with 65–70% of maximal heart rate. Blood was obtained pre and post-exercise to determine changes in serum BDNF, IGF-1 and platelets.

Results

After exercise, both the strength and endurance groups showed significant increases in serum BDNF and IGF-1 concentrations and platelets at post-exercise and in comparison to control group (p < 0.05). In addition, no statistically significant differences were detected between the strength and endurance groups at post-exercise.

Conclusion

Our findings indicate that both the strength and endurance interventions are effective in elevating BDNF, IGF-1, and platelets, without significant differences between them.

Co-treatment of AMPA endocytosis inhibitor and GluN2B antagonist facilitate consolidation and retrieval of memory impaired by β amyloid peptide

BACKGROUND

Glutamate neurotransmission stands as an important issue to minimize memory impairment. We investigated the effects of an inhibitor of α-amino-3-hydroxy-5-methyl-4-isozazole propionic acid receptors (AMPA) endocytosis and GluN2B subunit of N-methyl-d-aspartate receptors (NMDA), either isolated or combined, on memory impairments induced by Amyloid beta1-42 (Aβ).

METHODS

Eighty male Wistar rats were used for two experiments of consolidation and retrieval of memory. Memory impairment was induced by intracerebroventricular (ICV) injection of Aβ1-42 (2 μg/μl), and evaluated using Morris Water Maze (MWM). Each experiment consisted of 5 groups: Saline + Saline, Aβ + Saline, Aβ + Ifenprodil (Ifen, 3 nmol/ICV), Aβ +Tat-GluR23Y (3 µmol/kg/IP), and Aβ1 +Ifen + Tat-GluR23Y. Then, hippocampal cAMP-response element-binding protein (CREB) was measured by western blotting. Data were analyzed by Analysis of variance (ANOVA) repeated measure, and one-way Anova followed by Tukey's post hoc test.

RESULTS

During retrieval, Aβ+ Tat-GluR23Y showed significant improvement in total time spent (TTS) in the target quadrant (p = 0.009), escape latency to a platform (p = 0.008) and hippocampal level of CREB (p = 0.006) compared with Aβ + saline. Also, coadministration of Tat-GluR23Yand Ifen similar to Tat-GluR23Y alone caused significant improvement in TTS (p = 0.014) and latency to platform (p = 0.013). During consolidation, shorter escape latency (p = 0.001), longer TTS (p = 0.002) and higher level of hippocampal CREB were observed in the Aβ + Tat-GluR23Y (p = 0.001) and Aβ+ Tat-GluR23Y + Ifen (p = 0.017), respectively.

CONCLUSION

The present study provides pieces of evidence that inhibition of AMPARs endocytosis using Tat-GluR23Y facilitates memory consolidation and retrieval in Aβ induced memory impairment via the CREB signaling pathway.[Formula: see text].

The methanolic extract of Cinnamomum zeylanicum bark improves formaldehyde-induced neurotoxicity through reduction of phospho-tau (Thr231), inflammation, and apoptosis

Accumulation of formaldehyde (FA) in the brain is linked to age-related neurodegenerative disorders, as it accelerates memory impairment through tau protein aggregation, inflammation, and nuclear damage. This study aimed to assess the possible effects of methanolic cinnamon extract (CE) on FA-induced neurotoxicity in rats. The animals were treated with CE (100, 200, and 400 mg/kg, P.O.) for 30 days following FA administration (60 mg/kg, I.P.) for 30 days. Briefly, spatial and inhibitory memory were examined by Morris water maze (MWM) and passive avoidance (PA) tasks, respectively. The Nissl, Hoechst, and Bielschowsky silver staining methods were also used to assess apoptosis and neurofibrillary tangles (NFTs) in the hippocampal CA1 region, respectively. Brain tissues were probed with an anti-phospho-tau (Thr²³¹) monoclonal antibody to assess tau hyperphosphorylation. Inflammatory cytokines (IL-1β, IL-6, and TNF-α) were also measured by ELISA assay. Western blotting was performed to quantify the amount of phospho-tau (Thr²³¹), caspase-8, and caspase-9. The results showed that FA injection significantly caused tau hyperphosphorylation at Thr²³¹ residue, which in turn disturbed the MWM performance. The ratio of apoptotic to intact neurons increased following FA treatment. The results of Western blotting indicated that the hippocampal levels of phospho-tau (Thr²³¹) and caspase-8 were significantly higher in the FA group compared to the control group. The hippocampal levels of IL-1β, IL-6, and TNF-α in the FA group were also higher than the control group. Administration of 200 mg/kg of CE significantly improved the rats' MWM performance, decreased the levels of phospho-tau (Thr²³¹), caspase-8, IL-6, and TNF-α, and reduced the ratio of apoptotic to intact neurons. Overall, cinnamon improved cognitive performance in FA-treated rats by eliminating tau hyperphosphorylation, inflammatory cytokines, and nuclear damage.

Neuregulin1β improves both spatial and associative learning and memory in Alzheimer model of rats possibly through signaling pathways other than Erk1/2

BACKGROUND

Neuregulin-1β (NRG1 β) is associated with various neurological disorders such as schizophrenia, depression and Parkinson's disease. However, its role in Alzheimer's (AD) has not been understood yet. Here, we have studied the effect of NRG1 β and extracellular-signal-regulated kinase (ERK) signaling on special and associative memories and emotional stress in AD model of rats.

METHODS

Fifty six male Wistar rats were divided into eight groups of: Saline + Saline, Aβ + Saline, Aβ + NRG1β (5 μg/5 ul), Aβ + PBS, Aβ + NRG1β + PD98059 (PD, 5 μg/2 μl), Aβ + NRG1β + Saline and Saline + PD. AD model was induced by intracerebroventricular (ICV) injection of beta-amyloid protein (Aβ1-42, 4 μg/2 μl). The cognitive performances of rats were evaluated using Morris Water Maze (MWM) and Step through passive avoidance. Also locomotors activity and emotionality of animals were considered in an Open field test. Data were analyzed by one way Anova one way, repeated measure and T-test.

RESULTS

Significant improvement was found in spatial learning and memory assessed by total time spent in target quadrant [F (4, 32) = 12.4, p = 0.001], escape latency [F (4, 32) = 15.767, p = 0.001] and distance moved [F (4, 32) = 5.55, p = 0.002], in Aβ + NRG1β compared with Aβ + Saline in MWM. Also Aβ + NRG1β showed long latencies to enter into the dark compartment [F (4, 32) = 6.43, p = 0.001], but short time spent [F (4, 32) =6.93, p = 0.001] compared with control. Administration of an ERK inhibitor (PD98059, 5 μg, 15 min before NRG1β) didn't completely block learning memory restored by NRG1β in AD model (p = 0.7). No significant between groups differences was found in emotional stress characteristics in open field, except the grooming numbers which were higher in Saline + PD compared with Saline + Saline (p = 0.02).

CONCLUSION

Our findings indicate that NRG1β restores cognitive dysfunctions induced by amyloid β through signaling pathways possibly other than Erk1/2, with no significant change in anxiety, locomotion and vegetative activities.

Co-treatment of vitamin D supplementation and aerobic training improves memory deficit in ovariectomized rat

Objective: Metabolic syndrome (MetS) and insufficient vitamin D levels are globally increasing phenomena which are correlated with cognitive impairment. This study investigated the interactive effect of aerobic training with vitamin D supplementation on memory deficit in rats with metabolic syndrome induced by ovariectomy.Methods: A total of forty Wistar rats weighing 240-255 gr were randomly matched on their body weight and divided into ovariectomy (OVX, n = 32) and sham-operated (SHAM; n = 8) groups. OV group was then divided into vitamin D supplementation (OVX + Vit D; 10000 IU/kg/week, for 8 weeks, n = 8), aerobic training (OVX + AT; n = 8), aerobic training and vitamin D supplementation (OVX + AT + Vit D; 10000 IU/kg/week, for 8 weeks, n = 8), and vehicle control group receiving sesame oil (OVX + Ses Oil; n = 8). After the end of intervention, passive avoidance learning and memory were assessed in step through passive avoidance paradigm. Obtained data were analyzed by ANOVA and post hoc Tukey test.Results: After 8 weeks of aerobic training and vitamin D supplementation, step through dark compartment latency (STL) was significantly higher and total time spent in that compartment (TSD) was lower in OVX + AT + Vit D compared to the other counterpart groups.Conclusion: Vitamin D supplementation combined with 8-week aerobic training alleviates cognitive impairment metabolic syndrome induced by ovariectomy.

Comparing Oprm1 Gene Promoter Methylation in the Lymphocytes of Male Rats Addicted to Nicotine, Morphine, Methadone, and Buprenorphine

Background: Addiction is a polygenic disorder caused by genetic and environmental factors. The opioid material can act as an epigenetic element, like DNA methylation. Objectives: The present study aimed to examine the effect of epigenetic drugs such as nicotine, morphine, methadone, and buprenorphine on the methylation of two CpG sites in promoter of Oprm1 gene in male Wistar rats. Materials & Methods: In this case-control study, 48 male Wistar rats with Mean±SD (200±30) g were divided into 6 groups: These are five groups only The control (intact) group, nicotine (0.4 mg/kg, SC injection for 5 days), morphine (10 mg/kg on days 1-3 and 20 mg/kg on days 4-6 and 40 mg/kg, IP injection on days 7-9), methadone (0.5 mg/kg, IP injection for 15 days), buprenorphine (0.05 mg/kg, SC injection for 6 days) and finally saline for each respected group. After the treatment, genomic DNA was extracted from the whole blood of the rats. Then, the extracted DNA was treated with sodium bisulfate. To identify the selected methylated areas of Oprm1 promoter sites (CpG-107 and CpG+33), we used methylation-specific PCR (MSP). Results: Our results showed no methylation in the two CpG sites of Oprm1 promoter in all of the treated groups. Conclusion: Addiction with nicotine, morphine, methadone, and buprenorphine in doses and duration used in this study was not associated with the methylation of the Oprm1 promoter sites in the male Wistar rats.

Cinnamon extract combined with high-intensity endurance training alleviates metabolic syndrome via non-canonical WNT signaling

OBJECTIVES

The incidence of metabolic syndrome (MetS) in menopausal women is one of the main health care concerns. MetS clusters are related to an imbalance in pro- and anti-inflammatory adipokines such as secreted frizzled-related protein 5 (SFRP5) and wingless-type mammary tumor virus integration site family, member 5A (WNT5A). WNT5A induces an inflammatory state to induce insulin resistance and further pathologic consequences. Recent strategies to prevent progression of MetS to diabetes have focused on conservative treatments such as exercise and herbal medicine. The aim of this study was to investigate the mechanistic effects of cotreatment with cinnamon extract and 12-wk high-intensity endurance training on MetS components considering the non-canonical WNT5A signaling.

METHOD

Thirty-two female ovariectomized Wistar rats were divided into the following four groups (n = 8/group): exercise (Ova+Exe), cinnamon extract (Ova+Cin), exercise with cinnamon extract (Ova+Exe+Cin) and saline (Ova+Sal). One group of rats undergoing surgery without removal of the ovaries was considered as a sham. After 3 mo of experimental intervention, waist circumference, serum concentrations of glucose, insulin, lipid profile, tumor necrosis factor-α, WNT5A, and SFRP5 were measured.

RESULTS

Data showed a significant reduction in serum glucose, low-density lipoprotein, homeostasis model assessment estimate of insulin resistance, and tumor necrosis factor-α, but an increase in SFRP5 level in Ova+Exe, Ova+Cin and Ova +Exe+Cin groups compared with Ova+Sal group (P < 0.05). Serum WNT5A significantly was reduced only in Ova+Exe+Cin group (P = 0.02).

CONCLUSION

The present study indicated that high-endurance training combined with aqueous cinnamon extract supplementation for 12 wk more efficiently alleviated insulin resistance and metabolic dysfunctions via reduction in noncanonical WNT signaling in ovariectomized rats.

Flavonoids Fraction of Mespilus Germanica Alleviates Insulin Resistance in Metabolic Syndrome Model of Ovariectomized Rats via Reduction in Tumor Necrosis Factor-α

Objectives

The rate of metabolic syndrome (MetS) in women diagnosed as they age is one of the main concerns of health cares. Recently new strategies used to prevent progressions of MetS toward the diagnosis of diabetes have focused on plant flavonoids. This study was aimed to investigate the beneficial effects of flavonoids fraction of Mespilus germanica leaves (MGL) on MetS in ovariectomized (OVX) rats.

Methods

Twenty-four adult female Wistar rats, weighing 200 to 250 g, were divided into 3 groups: Sham surgery, OVX + Salin, or OVX + Flavonoid. Three weeks after ovariectomy, animals displayed MetS criteria received flavonoid injection (10 mg/kg, intraperitoneally) for 21 days. Then the body weight, body mass index, waist circumference, visceral fat, fasting blood glucose, serum insulin, lipid profiles and tumor necrosis factor-α (TNF-α) were measured.

Results

Treatment with flavonoids fraction of MGL significantly decreased serum level of insulin (P = 0.011), glucose (P = 0.024), TNF-α (P = 0.010), also MetS Z score (P = 0.020) and homeostasis model assessment of insulin resistance (P = 0.007). Lipid profiles and visceral fat showed insignificant reduction.

Conclusions

Flavonoids of MGL attenuates some of the MetS components possibly via reduction in TNF-α inflammatory cytokine.

Kaempferol attenuates cognitive deficit via regulating oxidative stress and neuroinflammation in an ovariectomized rat model of sporadic dementia

Alzheimer's disease (AD) is associated with oxidative stress, and ultimately results in cognitive deficit. Despite existing literature on the pathophysiology of AD, there is currently no cure for AD. The present study investigated the effects of kaempferol (Kmp) isolated from the extract of Mespilus germanica L. (medlar) leaves on cognitive impairment, hippocampal antioxidants, apoptosis, lipid peroxidation and neuro-inflammation markers in ovariectomized (OVX) rat models of sporadic AD. Kaempferol, as the main flavonoid of medlar extract has been previously known for anti-oxidative, anti-inflammatory and anti-neurotoxic effects. Thirty-two female Wistar rats were ovariectomized, and randomly divided into four groups: sham, OVX + saline, OVX + streptozotocin (STZ) + saline, OVX + STZ + Kmp. Animals received intracerebroventricular injection of STZ (3 mg/kg, twice with one day interval) to establish models of sporadic AD. Intraperitoneal injection of Kmp (10 mg/kg) for 21 days was performed in the OVX + STZ + Kmp group. Spatial learning and memory of rats were evaluated using a Morris water maze. Finally, brain homogenates were used for biochemical analysis by enzyme-linked immunosorbent assay. The results showed a significant improvement in spatial learning and memory as evidenced by shortened escape latency and searching distance in Morris water maze in the OVX + STZ + Kmp group compared with the OVX + STZ group. Kmp also exhibited significant elevations in brain levels of antioxidant enzymes of superoxide dismutase and glutathione, while reduction in tumor necrosis factor-α and malondialdehyde. Our results demonstrate that Kmp is capable of alleviating STZ-induced memory impairment in OVX rats, probably by elevating endogenous hippocampal antioxidants of superoxide dismutase and glutathione, and reducing neuroinflammation. This study suggests that Kmp may be a potential neuroprotective agent against cognitive deficit in AD.

Mental Training Enhances Cognitive Function and BDNF More Than Either Physical or Combined Training in Elderly Women With MCI: A Small-Scale Study

INTRODUCTION

The effects of mental, physical, and combination of these two trainings were investigated on cognitive performance, serum level of brain derived neurotrophic factor (BDNF), and irisin in women diagnosed with mild cognitive impairment (MCI).

MATERIAL AND METHODS

Forty-four participants were randomized into 4 groups: physical training (PH; 8 weeks' aerobic training, n = 11), mental training (ME; special computer gaming, n = 11), combined (PH + ME; n = 13), and control group (CO; n = 9).

RESULTS

Analysis of variance with Tukey post hoc test revealed a significant increase in working memory ( P = .012) and BDNF ( P = 0.024) in the ME compared with the CO group. Also the ME group in comparison with the PH group demonstrated better working memory ( P = .014) and processing speed ( P = .024).

CONCLUSION

Positive effect of mental training on the cognitive parameters, parallel with BDNF elevation, suggests that mental training is a more useful, safe, and persistent strategy to attenuate the progression of MCI probably via BDNF elevation, but the effect size is relatively small elevation.

The Effect of Estrogen Replacement Therapy on Visceral Fat, Serum Glucose, Lipid Profiles and Apelin Level in Ovariectomized Rats

Objectives

Ovarian hormones have been shown to regulate body weight, intra-abdominal fat accumulation and plasma level of cytokines. The aim of this study was to investigate the effect of estrogen replacement therapy on visceral adipose tissue, plasma level of apelin, lipid profiles, and glucose in ovariectomized (OVX) rats.

Methods

Thirty female Wistar rats were divided into OVX (n = 20) and sham (n = 10) groups. OVX rats were subdivided into estrogen replacement therapy (OVX+est; n = 10) receiving 17 β-estradiol valerates (30 µg/kg, s.c., 5 day/week, for eight weeks), and vehicle control group receiving sesame oil same as experiment group (OVX+ses oil; n = 10). After the treatments, all groups were sacrificed and blood samples were collected, visceral fats were taken from the abdominal cavity and weighed immediately. Apelin were measured using enzyme-linked immunosorbent assay kits. Lipid profiles and glucose were measured using the enzymatic colorimetric method. Data were analyzed with one-way analysis of variance and (P < 0.05) determined as the statistical significance level.

Results

After eight weeks, body weight, body mass index (BMI), visceral fat, apelin and lipid profiles (P < 0.01) were increased significantly in OVX rats compared to sham group. Treatment with estrogen leads to significant reduction in body weight and BMI (P < 0.05), there was no significant change in serum apelin level in OVX+est rats compared to OVX+ses.

Conclusions

These results suggest that estradiol replacement therapy successfully attenuated some of the metabolic syndrome components, and apelin does not probably stand as a mediator of these physiological functions.

Vitamin D is associated with metabotropic but not neurotrophic effects of exercise in ovariectomized rats

PURPOSE

Here, we studied the beneficial effects of aerobic exercise on metabolic syndrome components, cognitive performance, brain derived neurotrophic factor (BDNF) and irisin in ovariectomized rats with different serum vitamin D (Vit D) status.

METHODS

Eighty female wistar rats were divided into 2 groups of sham operated (sham, n = 8), and ovariectomized (OVX, n = 72). Then OVX were divided into 9 groups of receiving combination of exercise protocol with low dose of Vit D (OVX + EXE + LD), high dose of Vit D (OVX + EXE + HD), Vit D deficiency (OVX + EXE - D), and (OVX + EXE + Veh). Also non exercised groups of OVX receiving high dose of Vit D (OVX + HD), low dose of Vit D (OVX + LD), Vit D deficiency (OVX - D), and Veh (OVX + Veh) were included. After 2 months of related interventions, spatial memory was assessed using Morris water maze (MWM), and then metabolic syndrome components were measured.

RESULTS

High dose of Vit D supplementation showed significant reduction in weight (p = 0.001), lipid profiles (p = 0.001), visceral fat (p = 0.001) and waist circumference (p = 0.001) regardless of exercising or not, with no change in cognitiive function. Serum BDNF level was significantly higher in Vit D deficient group (p = 0.001), and was decreased in the OVX + HD. In contrary, irisin did not show any significant relationship with serum concentration of Vit D, while it was significantly elevated in the exercised groups compared with non-exercised counterparts.

CONCLUSION

Vit D insufficiency deteriorates metabolic syndrome components, and elevates serum BDNF as a compensatory metabotropic factor, and further supplementation significantly attenuates these components parallel with reduction in BDNF. In addition, aerobic exercise successfully induces various metabolic benefits, provided optimum serum level of Vit D.

Effect of exercise training on saliva brain derived neurotrophic factor, catalase and vitamin c

Background: The balance between production of Reactive Oxygen Species (ROS) and antioxidant defense in the body has important health implications. The aim of this study was to investigate the changes in salivary antioxidants: catalase, vitamin C and brain-derived neurotrophic factor (BDNF), in sedentary men at rest and after acute exhaustive exercise. Methods: This randomized controlled clinical trial (The registry code IRCT2011053212431N1) recruited twenty-five sedentary men (age=21±3yrs; height=172±8cm; weight=66±9kg; VO2 max=37.6±7.4mL•kgkg^-1•min^-1) participated in a double-blind randomized experiment. Unstimulated whole saliva samples were collected before, immediately and 1 hour after exhaustive treadmill running. Catalase, vitamin C (Vit C) concentration, and BDNF concentrations were determined using biochemical assays and ELISA respectively. Repeated measures ANOVA and Bonferroni posthoc test were used to analyze data. Results: The results of the present study showed that an acute intensive exercise causes a reduction in salivary catalase, Vit C and also BDNF concentration (p<0.05) compared with pre-exercise. Both catalase and Vit C showed a tendency to return to pre-exercise value after one hour. However, BDNF continued to reduction at least 1 hour after the ending of the training. Conclusion: Reduction in antioxidants capacity of saliva might reflects disturbance in natural antioxidant defense mechanisms of the body after an acute intensive physical stress and possible further health threatening consequences.

Influence of Sexuality in Functional Recovery after Spinal Cord Injury in Rats

BACKGROUND

Spinal cord injury (SCI) is a major clinical condition and research is commonly done to find suitable treatment options. However, there are some degrees of spontaneous recovery after SCI and gender is said to be a contributing factor in recovery, but this is controversial. This study was done to compare the effects of sexual dimorphism on spontaneous recovery after spinal cord injury in Wistar Rats.

METHODS

Spinal cord lesions were made by compressing the cord at T9 level and making a spinal cord contusion. Routine care of each rat was done daily. The LSS scoring system was used to measure the locomotion of these rats and to compare the recovery rate between male and female rats.

RESULTS

The results suggested that there was no significant difference between the two sex in recovery.

CONCLUSIONS

To be female does not seem to be a prognostic factor for recovery after SCI. However, this preliminary study should be repeated in other animals and in larger cohorts.

Palmitoylethanolamide attenuates PTZ-induced seizures through CB1 and CB2 receptors

Epilepsy is one of the most common neurologic disorders. Though there are effective medications available to reduce the symptoms of the disease, their side effects have limited their usage. Palmitoylethanolamide (PEA) has been shown to attenuate seizure in different animal models. The objective of the current study was to evaluate the role of CB1 and CB2 receptors in this attenuation. Male wistar rats were used for the current experiment. PTZ was injected to induce chemical kindling in animals. After verification of kindling in animals, treatment was performed with PEA, AM251 and AM630 in different groups. Latency to induce seizure, seizure stages and latency and duration of fifth stage of seizure was recorded for each animal. Injection of PTZ led to seizure in the animals. Pretreatment with PEA increased the latency to initiate seizures and reduced the duration of seizure. Pretreatment with different dosages of AM251 had contrary effects so that at lower doses they increased the seizure in animals but at higher doses led to the attenuation of seizure. AM630 increased seizures in a dose dependent manner. Combination of the antagonists increased the seizure parameters and attenuated the effect of PEA on seizure. PEA attenuated the PTZ-induced seizures and pretreatment with CB1 and CB2 antagonists diminished this effect of PEA, but still PEA was effective, which might be attributed to the contribution of other receptors in PEA anti-epileptic properties. Findings of the current study implied that endocannabinoid signaling pathway might have an important role in the effects of PEA.

The interaction effects of aerobic exercise training and vitamin D supplementation on plasma lipid profiles and insulin resistance in ovariectomized rats

Purpose

The purpose of this study was to determine the interaction effects of aerobic exercise training and vitamin D supplementation on indices of obesity and plasma lipid profiles in ovariectomized (OVX) rats.

Methods

Forty female Wistar rats were divided into 5 groups: aerobic training (3 days/week for 8 weeks; AT; n = 8), aerobic training and vitamin D supplementation (OVX + AT + Vit D; n = 8), vitamin D supplementation (OVX + Vit D; n = 8), ovariectomized control (OVX + C, n = 8) and SHAM (n = 8). After blood sampling, visceral fat was taken from the abdominal cavity and weighed immediately. Data was statistically analyzed by One-way ANOVA and Repeated measure ANOVA tests with a 0.05 significance level.

Results

Body weight, visceral fat, BMI and food intake decreased significantly in OVX + AT + Vit D (P < 0.001); whereas these variables increased significantly in OVX + C (P < 0.001) and SHAM (P < 0.023) groups. At the end of two-months of follow-up, we observed significant differences in TC, TG, HDL-C, LDL-C, glucose, insulin, and HOMA-IR in all groups.

Conclusion

It seems that aerobic training with vitamin D, due to the involvement of muscle mass and exposure to dynamic pressure on the bones and muscles, increased energy expenditure, stimulated insulin exudation and glucose homeostasis, decreased insulin resistance and improved the lipid profile in ovariectomized rats.

Effect of six weeks of endurance exercise and following detraining on serum brain derived neurotrophic factor and memory performance in middle aged males with metabolic syndrome

AIM

Brain derived neurotrophic factor (BDNF) and physical inactivity contribute to the development of metabolic syndrome (MetS). Aerobic training has been reported to improve MetS, however less attention has been directed toward the role of training and detraining on cognitive function in MetS.

METHODS

Twenty one healthy middle-aged males and 21 with MetS were distributed into four groups: MetS exercise (ME), MetS control (MC), Healthy exercise (HE) and healthy control (HC). Both ME and HE, followed a 6-week aerobic training program (3 sessions/week). Digit Span memory test and blood sampling were conducted pre training, post training and also following a six weeks detraining. Data were analyzed using spearman, pearson and repeated measure ANOVA tests.

RESULTS

Baseline serum BDNF level was positively correlated with waist circumference (r=0.383, P=0.012) and showed significant elevation in MetS compared with healthy subjects (1101.66±61.34 vs. 903.72±46.57 pg/mL, P=0.014). After aerobic exercise BDNF level significantly increased in HE, but decreased in ME group (P=0.001). Both short and mid term memory significantly increased (P<0.05) only in HE group.

CONCLUSION

Exercise induced cognitive improvement might be mediated via BDNF-linked mechanisms in healthy people. However, the health status of individuals should be considered.

Transplanted bone marrow mesenchymal stem cells improve memory in rat models of Alzheimer's disease

The present study aims to evaluate the effect of bone marrow mesenchymal stem cells (MSCs) grafts on cognition deficit in chemically and age-induced Alzheimer's models of rats. In the first experiments aged animals (30 months) were tested in Morris water maze (MWM) and divided into two groups: impaired memory and unimpaired memory. Impaired groups were divided into two groups and cannulated bilaterally at the CA1 of the hippocampus for delivery of mesenchymal stem cells (500 × 10(3)/μL) and PBS (phosphate buffer saline). In the second experiment, Ibotenic acid (Ibo) was injected bilaterally into the nucleus basalis magnocellularis (NBM) of young rats (3 months) and animals were tested in MWM. Then, animals with memory impairment received the following treatments: MSCs (500 × 10(3)/μL) and PBS. Two months after the treatments, cognitive recovery was assessed by MWM in relearning paradigm in both experiments. Results showed that MSCs treatment significantly increased learning ability and memory in both age- and Ibo-induced memory impairment. Adult bone marrow mesenchymal stem cells show promise in treating cognitive decline associated with aging and NBM lesions.

Effects of ovariectomy and estrogen replacement therapy on visceral adipose tissue and serum adiponectin levels in rats

BACKGROUND

Excess visceral adipose tissue accumulation after menopause is closely associated with decreased insulin sensitivity and adiponectin levels.

OBJECTIVE

The purpose of this study was to determine the effect of ovariectomy and estrogen replacement on visceral fat and serum adiponectin levels in ovariectomized (OVX) rats.

METHOD

Forty 11-week-old female Wistar rats were divided into the four following groups (n = 10 rats per group): sham-operated control (SHAM); sedentary OVX (OVX-SED); OVX with estrogen replacement (OVX-ER); and OVX with sesame oil treatment (OVX-C). Rats in OVX-ER and OVX-C groups received 17β-estradiol valerate (30 µg/kg, subcutaneously) and sesame oil as vehicle, five days a week, respectively. All animals were sacrificed after eight weeks of intervention.

RESULTS

Ovariectomy after eight weeks increased body weight and visceral fat (P < 0.05) in OVX-SED and OVX-C groups compared with SHAM rats with no change in plasma adiponectin levels. Estrogen replacement in OVX animals decreased body weight (13.4%, P < 0.05) and visceral fat (10.4%). Although they were not statistically significant, adiponectin, insulin sensitivity and lipid profile of OVX rats were ameliorated with estrogen treatment.

CONCLUSION

We conclude that ovarian hormone withdrawal leads to higher body weight and visceral adipose tissue in rats, but surprisingly does not change adiponectin levels. Although a substantial decrease in body weight was achieved by estrogen replacement therapy in OVX animals, the beneficial metabolic effects of weight loss seems to be only mechanical, having a tendency to improve insulin sensitivity without elevating adiponectin production.

Dopaminergic activity in the medial prefrontal cortex modulates fear conditioning

The purpose of the present study was to determine the role of medial prefrontal cortex (mPFC) dopaminergic system in fear conditioning response considering individual differences. Animals were initially counterbalanced and classified based on open field test, and then were given a single infusion of the dopamine agonist, amphetamine (AMPH) and antagonist, clozapine (CLZ) into the medial prefrontal cortex. Rats received tone-shock pairing in a classical fear conditioning test and then exposed to the tone alone. Freezing responses were measured as conditioned fear index. The results showed that both AMPH and CLZ infusion in mPFC reduced the expression of conditioned fear. This finding indicates that elevation or reduction in the dopaminergic activity is associated with the decrease of fear responses, despite preexisting individual-typological differences.

Effect of vitamin C supplementation on lipid peroxidation, muscle damage and inflammation after 30-min exercise at 75% VO2max

AIM

Hypothetically, supplementation with the antioxidant vitamins C could alleviate exercise-induced lipid peroxidation. The purpose of this study was to evaluate the effect of vitamin C supplementation on exercise-induced lipid peroxidation, muscle damage and inflammation.

METHODS

Sixteen healthy untrained male volunteers participated in a 30-min exercise at 75% Vo2max. Subjects were randomly assigned to one of two groups: 1) placebo and 2) vitamin C (VC: 1 000 mg vitamin C). Blood samples were obtained prior to supplementation (baseline), 2 h after supplementation (immediately pre-exercise), post-exercise, 2 and 24 h after exercise. Plasma levels of VC, total antioxidant capacity (TAC), creatine kinase (CK), malondealdehyde (MDA), total leukocytes, neutrophils, lymphocytes, interleukin-6 (IL-6) and cortisol were measured.

RESULTS

Plasma vitamin C concentrations increased significantly in the VC in response to supplementation and exercise (P<0.05). TAC decreased significantly in Placebo group 24 h after exercise compared to pre-exercise (P<0.05). Although MDA levels were similar between groups at baseline, it increased significantly 2 h after exercise only in the Placebo group (P<0.05). CK increased immediately and 2 h after exercise in both groups and 24 h after exercise only in placebo group compared to pre-exercise (P<0.05). Markers of inflammation (total leukocyte counts, neutrophil counts and IL-6) were increased significantly in response to the exercise (P<0.05). In VC group, there was significant increase in lymphocyte counts immediately after exercise compared with pre-exercise (P<0.05). Serum cortisol concentrations significantly declined after supplementation compared with baseline (P<0.05) as well as declined 2 and 24 h after exercise compared with immediately after exercise in VC group (P<0.05).

CONCLUSION

VC supplementation prevented endurance exercise-induced lipid peroxidation and muscle damage but had no effect on inflammatory markers.

[c-fos Gene expression in the brain of rats with various exploratory and defensive behavior]

Groups of active and passive Wistar rats were revealed in the "open field" and "hole exploration" tests. The pronounced c-fos gene expression was found in different brain structures of rats preliminary subjected to electrodermal stimulation in the "step down" test. Marked differences in c-fos gene expression were observed in brain structures of rats with the active and passive behavior in the "open field", "hole exploration", and "step down" tests. The most pronounced and intensive c-fos gene expression was noticed in the passive rats.