Diabetes is one of the risk factors for the development of vascular dementia (VD), leading to endothelial dysfunction and cognitive impairment. Resveratrol has been shown to have antioxidant, ...antiinflammatory, and neuroprotective effects. The previous studies have also reported that resveratrol improves cognitive and vascular endothelial functions in several pathological conditions. In the present study we aimed to evaluate the effect of resveratrol on cognitive and vascular endothelial function and to explore the mechanisms of its effects in the streptozotocin-induced diabetic rat model of VD. Male Wistar rats were divided into 3 groups (n = 10 in each group): Control, diabetes (DM), DM + resveratrol (DM + RSV) groups. Rats from the DM + RSV group received resveratrol (20 mg/kg/day, ip) for 4 weeks after induction of diabetes and then cognitive functions of the rats were tested by the Morris water maze and a passive avoidance tests. After behavioral tests, endothelial function of thoracic aorta (the endothelium-dependent and -independent vasorelaxant responses) was investigated. To explore the mechanisms of resveratrol, endothelial eNOS, aortic superoxide dismutase (SOD), NADPH oxidase, heme oxygenase-1 (HO-1) levels, TNF-α and IL-1β expressions; serum SOD and NADPH oxidase levels and, hippocampal BDNF, TNF-α and IL-1β expressions were measured. It was shown that DM resulted in severe learning and memory deficits associated with endothelial dysfunction, increased expression of TNF-α and IL-1β, increased oxidative stress levels and decreased expression of eNOS and BDNF. In contrast, resveratrol treatment improved the cognitive decline. It was also found that chronic treatment with resveratrol ameliorated the impaired vascular reactivity. Reveratrol significantly reversed diabetes-induced changes of protein expression. Our data suggest that resveratrol prevents memory deficits, endothelial dysfunction, increased oxidative stress, inflammation and impairment of neurotrophin expression in a VD rat model. Thus, the vasculoprotective and neuroprotective effects of resveratrol may be beneficial in DM patients.
•Unpredictable chronic mild stress (UCMS) impairs learning and memory in MWM and PAT.•UCMS decreases expression of BDNF in CA1 and CA3 fields of hippocampus.•Chronic administration of Infliximab ...prevents stress-induced memory impairment.•Chronic administration of Infliximab prevents stress-induced reduction in hippocampal BDNF.
Previous findings have shown that patients with depression express higher levels of proinflammatory cytokines such as TNF-α and IL-6. We have recently found that Infliximab (a TNF-α inhibitor) decreased anhedonia and despair-like behavior in the rat unpredictable chronic mild stress (UCMS) model of depression suggesting that inflammation might play an important role in depression. An increasing number of studies suggest that inflammation is also associated with cognitive impairments. The current study aimed to investigate the effect of UCMS on the cognitive performance of rats and their hippocampal BDNF levels and the effect of chronic Infliximab (5mg/kg/weekly, i.p.) treatment on these measures. Rats were subjected to different types of stressors daily for a period of 56 days to induce depression-like state. The UCMS resulted in impairments in spatial and emotional memory acquisition and retention with no effect on the level of locomotor activity. These behavioral effects of UCMS were accompanied by reduction in the level of BDNF in the CA1 and CA3 regions of the hippocampus. Chronic Infliximab treatment prevented the UCMS-induced cognitive impairments as well as the reduction in the levels of hippocampal brain-derived neurotrophic factor (BDNF). These results suggest that Infliximab improves the spatial and emotional memory impairments induced by chronic stress in rats likely through its effects on hippocampal function by modulating inflammation.
We investigated the effect of resveratrol on endothelial and neuronal nitric oxide synthase (eNOS and nNOS) expression in the corpus cavernosum from chronic unpredictable mild stress (CUMS)-exposed ...rats in order to examine possible role of proinflammatory cytokines, which might play a role on erectile dysfunction (ED). Rats were randomly and equally divided into four groups such as control, control+resveratrol, CUMS and CUMS + resveratrol (20 mg/kg/day, i.p/8 weeks). Sucrose intake and forced swimming tests were used to evaluate depressive-like behaviors. nNOS, eNOS expressions, inflammatory markers, corticosterone and testosterone levels were analyzed either in blood samples and/or penile tissues. CUMS-exposed rats displayed depressive-like behaviors, reduced penile nNOS and eNOS expressions, and serum testosterone levels and enhanced serum and penile tissue levels of proinflammatory markers compared to controls. Resveratrol reversed depressive-like behaviors and suppressed serum and penile levels of proinflammatory markers, increased nNOS and eNOS expressions and testosterone levels in CUMS-exposed rats. Resveratrol exerted antidepressant-like effects and protected the development of CUMS-induced impairment of cavernosal eNOS and nNOS expressions associated with ED, which might be related to its anti-inflammatory action.
Chronic stress is associated with male sexual problems including ejaculatory dysfunctions. The aim of this study was to determine whether resveratrol (RS) or quercetin (QE) has protective effects on ...vas deferens (VD) contractility in the unpredictable chronic mild stress (UCMS) rat model of depression. Animals were separated into six groups: control, control + RS and control + QE, stress, stress + RS, and stress + QE. Stress groups were subjected to UCMS procedure for 5 weeks. Animals in treatment groups were injected intraperitoneally with RS (20 mg/kg) or QE (30 mg/kg) for 5 weeks during UCMS period. UCMS caused depressive-like behaviors and enhanced systemic levels of corticosterone. The nerve-evoked contractile responses of VD significantly impaired and, noradrenaline- and ATP-induced contractile responses of VD significantly increased in stressed rats. UCMS exposure also markedly enhanced oxidative stress and inflammation in VD tissues. Treatment with RS or QE significantly ameliorated all the aforementioned parameters. The current study demonstrated that RS or QE protected against chronic stress-induced VD dysfunction by their antioxidant and anti-inflammatory effects on VD, suggesting that oxidative stress and inflammation may be synergistic parts in the development of VD dysfunction associated with chronic stress-induced depression.
Psychological stress may lead to erectile dysfunction (ED), and inflammation has been evaluated as a major contributing factor. The goal of this study was to investigate the effects of etanercept ...(ETN), an anti-tumor necrosis factor α (TNF-α) protein, on cavernosal function in the unpredictable chronic mild stress (UCMS) rat model of depression. Animals were divided into 4 groups: animals not exposed to UCMS, animals not exposed to UCMS and treated with ETN, animals exposed to UCMS, and animals treated with ETN while exposed to UCMS. UCMS significantly impaired the neurogenic and endothelium-dependent relaxation responses; reduced cavernosal endothelial nitric oxide (NO) synthase (eNOS) and neuronal NO synthase (nNOS) expressions; decreased testosterone levels; enhanced systemic levels of corticosterone, TNF-α, interleukin 1β (IL-1β), interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule 1 (ICAM-1); and also increased cavernosal levels of TNF-α, IL-1β, and IL-6 in rats. ETN administration restored NO-mediated neurogenic and endothelium-dependent relaxation responses of the corpus cavernosum, increased cavernosal eNOS and nNOS expressions, enhanced testosterone levels, and decreased corticosterone levels in UCMS-exposed rats. Also, systemic inflammatory markers and cavernosal proinflammatory cytokine levels were reduced by ETN. Our results demonstrate the role of TNF-α-mediated inflammation in the development of depression and ED in rats exposed to chronic stress.
•Memory impairment and depression-like behaviors were observed in 8-month-old WAG/Rij rats.•TNF alpha inhibition by etanercept rescued these impairments.•Etanercept decreased the number of seizures ...without changing the seizure duration in WAG/Rij rats.
Pro-inflammatory cytokines have been shown to be associated with the development of seizures in the WAG/Rij rat model of absence epilepsy. Importantly, WAG/Rij rats also exhibit cognitive deficits and depression-like behaviors. It is possible that pro-inflammatory cytokines mediate these comorbid conditions of absence epilepsy given their well-established effects on cognition and affective responses. The current study investigated the potential therapeutic effect of etanercept (tumor necrosis factor inhibitor) on cognitive impairment, depression-like behavior, and spike-wave discharges (SWDs) typically observed in the WAG/Rij rats. Eight-month-old male WAG/Rij rats and Wistar controls were tested in Morris water maze (MWM), passive avoidance (PA), forced swimming, sucrose preference, and locomotor activity tests, and electroencephalogram (EEG) recordings were taken from a separate group of WAG/Rij rats after 8 weeks of etanercept or vehicle treatment. Consistent with earlier work, WAG/Rij rats exhibited cognitive deficits and depression-like behavior. From these, the cognitive deficits and despair-like behavior were rescued by etanercept administration, which also reduced the frequency of SWDs without affecting their duration. Our results support the hypothesis that pro-inflammatory cytokines mediate the absence seizures and comorbid symptoms of absence epilepsy.
Chronic stress is an important public health problem known as a risk factor for depression, cognitive deficits, and also erectile dysfunction (ED). Resveratrol, a plant polyphenol, was reported to ...activate constitutive endothelial nitric oxide synthase (eNOS). Although resveratrol has been proven to exert beneficial effects on the unpredictable chronic mild stress (UCMS)-induced decline in cognitive functions, its potential protecting effect on the penile tissue subjected to UCMS was in fact not investigated. Therefore, restorative effects of resveratrol on neurogenic and endothelium-dependent relaxations were evaluated in the corpus cavernosum of rabbits exposed to UCMS. Eighteen male New Zealand white rabbits were assigned into three groups (n = 6 in each group): controls; UCMS; and UCMS rabbits treated with resveratrol (20 mg/kg/day, i.p.) for 12-week period of stress induction. UCMS was induced by a couple of defined adverse conditions applied in a shuffled order for 12 weeks. Neurogenic and endothelium-dependent relaxations of corpus cavernosum were assessed by using organ bath studies. Both the electrical field stimulation (EFS)-induced neurogenic and carbachol-induced endothelium-dependent relaxant responses significantly decreased in physiological stress and resveratrol treatment exhibited a marked improvement in these relaxation responses in vitro. Our results indicated that chronic psychological stress could lead to ED by reducing neurogenic and endothelium-dependent relaxations and resveratrol prevents impairment of the functional responses, suggesting a potential new treatment approach for treatment of ED during psychological stress.
•Normal aging resulted in cognitive deficits and endothelial dysfunction.•Etanercept reversed aging-induced impairments in cognitive and endothelial functions.•Etanercept prevented aging-induced ...peripheral and neuroinflammation.•BDNF expression decreased in aged rats brain and etanercept prevented this reduction.•Etanercept may be beneficial for cognitive abilities in aging.
Normal aging may lead to cognitive deficits, which is associated with endothelial dysfunction and neuroinflammation. Dysregulation of TNFα expression contributes to vascular aging and dementia. In this study, we investigated the effects of etanercept, which is a TNFα inhibitor, on cognitive and endothelial function in aged rats. Male Wistar albino rats were divided into 3 groups: Young (4 month), aged (24 month) aged+ETA (24 month+etanercept). Etanercept (0.8 mg/kg/weekly) was given to the aged+ETA group subcutaneously for 8 weeks. Then passive avoidance test (PAT) and the Morris water maze test (MWMT) were used to evaluate cognitive functions of rats. After the behavioral tests, the rats were subjected to systolic blood pressure (SBP) measurement, and then endothelial function of thoracic aorta was evaluated by isolated organ bath system. Thoracic eNOS expression, hippocampal BDNF expression and serum and hippocampal TNF levels were also measured. In aged rats, it was shown that cognitive performances in MWMT and PAT were abolished whereas SBP unchanged. Furthermore, aging resulted in endothelial dysfunction, decreased expressions of thoracic eNOS and hippocampal BDNF, and increased level of TNF in serum and hippocampus. In contrast, ETA improved age-related cognitive deficits and endothelial dysfunction. In addition, ETA reversed changes in protein expression in aged rats. The results of this study indicate that ETA prevents cognitive deficits, endothelial dysfunction, peripheral and neuro-inflammation and decreament of neurotrophin expression in aged rats. These findings suggest that ETA may be beneficial with neuroprotective and vasculoprotective effects in elderly patients.
Obesity is associated with endothelial dysfunction and this relationship is probably mediated in part by inflammation.
The current study evaluated the effects of etanercept, a tumor necrosis ...factor-alpha (TNF-α) inhibitor, on endothelial and vascular reactivity, endothelial nitric oxide synthase (eNOS) immunoreactivity, and serum and aortic concentrations of TNF-α in a diet-induced rat model.
Male weanling Wistar rats were exposed to a standard diet and cafeteria diet (CD) for 12 weeks and etanercept was administered during CD treatment. Isolated aortas of the rats were used for isometric tension recording. Carbachol-induced relaxant responses were impaired in CD-fed rats, while etanercept treatment improved these endothelium-dependent relaxations. No significant change was observed in papaverine- and sodium nitroprusside (SNP)-induced relaxant responses. eNOS expression decreased in CD-fed rats, but no change was observed between etanercept-treated CD-fed rats and control rats. CD significantly increased both the serum and the aortic levels of TNF-α, while etanercept treatment suppressed these elevated levels. CD resulted in a significant increase in the body weight of the rats. Etanercept-treated (ETA) CD-fed rats gained less weight than both CD-fed and control rats.
Erectile dysfunction (ED) has been reported to be associated with inflammation. This study investigated the effects of tumor necrosis factor alpha (TNF-alpha) inhibitor etanercept on penile neuronal ...nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) expressions, testosterone concentrations, neurogenic and endothelium-dependent relaxations of corpus cavernosum (CC), and circulating and cavernosal levels of inflammatory markers in aged rats. Animals were separated into control, aged, and etanercept-treated aged groups. Aged rats displayed significantly increased serum and cavernosal TNF- alpha, C-reactive protein (CRP), monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule (ICAM-1) levels, and decreased penile nNOS and eNOS expressions and serum testosterone levels compared with controls. In etanercept-treated aged group, NOS expressions were similar to that of the control group. The circulating and cavernosal concentrations of TNF-alpha, CRP, MCP-1, ICAM-1, and testosterone were also normalized by etanercept. Neurogenic and endothelium-dependent relaxant responses significantly decreased in aged rats and etanercept treatment markedly improved these relaxation responses. Our findings indicate that aging decreases penile NOS expression, neurogenic and endothelium-dependent relaxations of CC, and also suppresses serum testosterone levels by inducing inflammatory response that may contribute to the development of ED. TNF-alpha antagonism may be a novel strategy to treat aging-associated ED.
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