Soy isoflavone attenuates brain mitochondrial oxidative stress induced by β-amyloid peptides 1-42 injection in lateral cerebral ventricle

Kolaviron neuroprotective effect against okadaic acid-provoked cognitive impairment

Alzheimer's disease (AD) is acknowledged as the main causative factor of dementia that affects millions of people around the world and is increasing at increasing pace. Okadaic acid (OA) is a toxic compound with ability to inhibit protein phosphatases and to induce tau protein hyperphosphorylation and Alzheimer's-like phenotype. Kolaviron (KV) is a bioflavonoid derived from Garcinia kola seeds with anti-antioxidative and anti-inflammation properties. The main goal of this study was to assess whether kolaviron can exert neuroprotective effect against okadaic acid-induced cognitive deficit. Rats had an intracerebroventricular (ICV) injection of OA and pretreated with KV at 50 or 100 mg/kg and examined for cognition besides histological and biochemical factors. OA group treated with KV at 100 mg/kg had less memory deficit in passive avoidance and novel object discrimination (NOD) tasks besides lower hippocampal levels of caspases 1 and 3, tumor necrosis factor α (TNFα) and interleukin 6 (IL-6) as inflammatory factors, reactive oxygen species (ROS), protein carbonyl, malondialdehyde (MDA), and phosphorylated tau (p-tau) and higher level of acetylcholinesterase (AChE) activity, mitochondrial integrity index, superoxide dismutase (SOD), and glutathione (GSH). Moreover, KV pretreatment at 100 mg/kg attenuated hippocampal CA1 neuronal loss and glial fibrillary acidic protein (GFAP) reactivity as a factor of astrogliosis. In summary, KV was able to attenuate cognitive fall subsequent to ICV OA which is partly mediated through its neuroprotective potential linked to mitigation of tau hyperphosphorylation, apoptosis, pyroptosis, neuroinflammation, and oxidative stress and also improvement of mitochondrial health.

Ulinastatin ameliorated streptozotocin-induced diabetic nephropathy: Potential effects via modulating the components of gut-kidney axis and restoring mitochondrial homeostasis

Growing evidence supports the role of the gut-kidney axis and persistent mitochondrial dysfunction in the pathogenesis of diabetic nephropathy (DN). Ulinastatin (UTI) has a potent anti-inflammatory effect, protecting the kidney and the gut barrier in sepsis, but its effect on DN has yet to be investigated. This study aimed to assess the potential mitigating effect of UTI on DN and investigate the possible involvement of gut-kidney axis and mitochondrial homeostasis in this effect. Forty male Wistar rats were divided equally into four groups: normal; UTI-treated control; untreated DN; and UTI-treated DN. At the end of the experiment, UTI ameliorated DN by modulating the gut-kidney axis as it improved serum and urinary creatinine, urine volume, creatinine clearance, blood urea nitrogen, urinary albumin, intestinal morphology including villus height, crypt depth, and number of goblet cells, with upregulating the expression of intestinal tight-junction protein claudin-1, and counteracting kidney changes as indicated by significantly decreasing glomerular tuft area and periglomerular and peritubular collagen deposition. In addition, it significantly reduced intestinal and renal nuclear factor kappa B (NF-κB), serum Complement 5a (C5a), renal monocyte chemoattractant protein-1 (MCP-1), renal intercellular adhesion molecule 1 (ICAM1), and renal signal transducer and activator of transcription 3 (STAT3), mitochondrial dynamin related protein 1 (Drp1), mitochondrial fission 1 protein (FIS1), mitochondrial reactive oxygen species (ROS), renal hydrogen peroxide (H2O2), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. Furthermore, it significantly increased serum short chain fatty acids (SCFAs), and mitochondrial ATP levels and mitochondrial transmembrane potential. Moreover, there were significant correlations between measured markers of gut components of the gut-kidney axis and renal function tests in UTI-treated DN group. In conclusion, UTI has a promising therapeutic effect on DN by modulating the gut-kidney axis and improving renal mitochondrial dynamics and redox equilibrium.

Soy isoflavone reduces LPS-induced acute lung injury via increasing aquaporin 1 and aquaporin 5 in rats

Acute lung injury (ALI) followed with severe inflammation and oxidative stress. Anti-inflammatory and antioxidant are the properties of aquaporin 1 (AQP1) and aquaporin 5 (AQP5). The goal of this study was to see if soy isoflavone can diminish lipopolysaccharide (LPS)-induced ALI and the underling mechanism. LPS-induced ALI was given to Sprague-Dawley rats 14 days following oophorectomy. One hour before the LPS challenge, estradiol (1 mg/kg) was administered subcutaneously as positive control and soy isoflavone was intragastric administration for 14 days prior to LPS challenge with different doses. Six hours after LPS challenge, the pulmonary edema, pathophysiology, inflammation, and the oxidative stress in lung tissues of rats were discovered. We found that soy isoflavone can reduce pulmonary edema and the lung pathology in a dose-dependent manner. Furthermore, tumor necrosis factor-alpha, interleukin-1β, and interleukin-6 were decreased in rats treated with soy isoflavone. Meanwhile, soy isoflavone reduced pulmonary oxidative stress by decreasing malondialdehyde levels, while increasing superoxide dismutase levels in lung tissues in a dose-dependent manner. Mechanically, we found that the mRNA and protein level of AQP1 and AOP5 were increased in lung tissues of rats treated with soy isoflavone compared the LPS-treated rats. Thus, soy isoflavone alleviates LPS-induced ALI through inducing AQP1 and AQP5.

Role of soy lecithin combined with soy isoflavone on cerebral blood flow in rats of cognitive impairment and the primary screening of its optimum combination

BACKGROUND/OBJECTIVES

Soy isoflavone (SIF) and soy lecithin (SL) have beneficial effects on many chronic diseases, including neurodegenerative diseases. Regretfully, there is little evidence to show the combined effects of these soy extractives on the impairment of cognition and abnormal cerebral blood flow (CBF). This study examined the optimal combination dose of SIF + SL to provide evidence for improving CBF and protecting cerebrovascular endothelial cells.

MATERIALS/METHODS

In vivo study, SIF50 + SL40, SIF50 + SL80 and SIF50 + SL160 groups were obtained. Morris water maze, laser speckle contrast imaging (LSCI), and hematoxylin-eosin staining were used to detect learning and memory impairment, CBF, and damage to the cerebrovascular tissue in rat. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) and the oxidized glutathione (GSSG) were detected. The anti-oxidative damage index of superoxide dismutase (SOD) and glutathione (GSH) in the serum of an animal model was also tested. In vitro study, an immortalized mouse brain endothelial cell line (bEND.3 cells) was used to confirm the cerebrovascular endothelial cell protection of SIF + SL. In this study, 50 μM of Gen were used, while the 25, 50, or 100 μM of SL for different incubation times were selected first. The intracellular levels of 8-OHdG, SOD, GSH, and GSSG were also detected in the cells.

RESULTS

In vivo study, SIF + SL could increase the target crossing times significantly and shorten the total swimming distance of rats. The CBF in the rats of the SIF50 + SL40 group and SIF50 + SL160 group was enhanced. Pathological changes, such as attenuation of the endothelium in cerebral vessels were much less in the SIF50 + SL40 group and SIF50 + SL160 group. The 8-OHdG was reduced in the SIF50 + SL40 group. The GSSG showed a significant decrease in all SIF + SL pretreatment groups, but the GSH showed an opposite result. SOD was upregulated by SIF + SL pretreatment. Different combinations of Genistein (Gen)+SL, the secondary proof of health benefits found in vivo study, showed they have effective anti-oxidation and less side reaction on protecting cerebrovascular endothelial cell. SIF50 + SL40 in rats experiment and Gen50 + SL25 in cell test were the optimum joint doses on alleviating cognitive impairment and regulating CBF through protecting cerebrovascular tissue by its antioxidant activity.

CONCLUSIONS

SIF+SL could significantly prevent cognitive defect induced by β-Amyloid through regulating CBF. This kind of effect might be attributed to its antioxidant activity on protecting cerebral vessels.

Lipoxin A4 attenuated dexamethasone-induced muscle atrophy via activation of PGC-1α/Nrf2/TFAM pathway

Prolonged dexamethasone (DEX) administration causes skeletal muscle atrophy through induction of both oxidative stress and mitochondrial dysfunction. Lipoxin A4 (LXA4) is a recognized antioxidant but its effect against DEX-induced muscle atrophy has not been studied yet. This study aimed to assess the potential ameliorating effect of LXA4 on DEX-induced muscle atrophy and investigate the possible involvement of the mitochondrial dynamics pathway and the redox state in this effect. Forty male rats were divided into four groups; normal control, LXA4-treated, DEX-treated, and LXA4 plus DEX-treated. At the end of the experiment, LXA4 counteracted the effect of DEX on different parameters including muscle weight, muscle strength, serum creatine kinase activity, malondialdehyde and protein carbonyl contents, Na/K-ATPase and citrate synthase activities, mitochondrial transmembrane potential, mitochondrial transcription factor (TFAM), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and nuclear factor erythroid 2-related factor 2 (Nrf2). These findings signify the promising therapeutic effect of LXA4 against DEX-induced skeletal muscle atrophy and indicate the possible involvement of LXA4-induced mitochondrial activation in addition to its well-known antioxidant effects.

Protective effect of N-acetyl cysteine on the mitochondrial dynamic imbalance in temporal lobe epilepsy: Possible role of mTOR

Understanding the underlying molecular mechanisms involved in epilepsy is critical for the development of more effective therapies. It is believed that mTOR (Mechanistic Target of Rapamycin kinases) activity and the mitochondrial dynamic balance change during epilepsy. mTOR affects mitochondrial fission by stimulating the translation of mitochondrial fission process 1 (MTFP1). In This study, the protective role of N-acetylcysteine was studied in temporal lobe epilepsy (TLE) through the regulation of mTOR and mitochondrial dynamic proteins. Rats received N-acetylcysteine (oral administration) seven days before induction of epilepsy, followed by one day after epilepsy. TLE was induced by microinjection of kainite into the left lateral ventricle. The total mTOR and Drp1 levels in the hippocampus were evaluated by western blotting. MFN1 was assessed using immunohistochemistry, and the expression of Fis.1 and MTFP1 (fission-related proteins) and OPA (fusion-related protein) were detected by real-time PCR. The mitochondrial membrane potential was measured by Rhodamin 123. The results showed that 72 h after induction of epilepsy, the mTOR protein level increased, and the balance of the mitochondrial dynamic was disturbed; however, oral administration of NAC decreased the mTOR protein level and improved the mitochondrial dynamic. These findings indicate that NAC plays a neuroprotective role in temporal lobe epilepsy, probably through decreasing the mTOR protein level, which can improve the imbalance in the mitochondrial dynamic.

Sinomenine Attenuates Trimethyltin-Induced Cognitive Decline via Targeting Hippocampal Oxidative Stress and Neuroinflammation

Sinomenine is the main bioactive ingredient of the medicinal plant Sinomenium acutum with neuroprotective potential. This study was designed to assess beneficial effect of sinomenine in alleviation of trimethyltin (TMT)-induced cognitive dysfunction. TMT was administered i.p. (8 mg/kg, once) and sinomenine was daily given p.o. 1 h after TMT for 3 weeks at doses of 25 or 100 mg/kg. Cognitive performance was assessed in various behavioral tests. In addition, oxidative stress- and inflammation-associated factors were measured and histochemical evaluation of the hippocampus was conducted. Sinomenine at a dose of 100 mg/kg significantly and partially increased discrimination index in novel object recognition (NOR), improved alternation in short-term Y maze, increased step-through latency in passive avoidance paradigm, and also reduced probe trial errors and latency in the Barnes maze task. Moreover, sinomenine somewhat prevented inappropriate hippocampal changes of malondialdehyde (MDA), reactive oxygen species (ROS), protein carbonyl, nitrite, superoxide dismutase (SOD), tumor necrosis factor α (TNFα), interleukin 6 (IL 6), acetylcholinesterase (AChE) activity, beta secretase 1 (BACE 1) activity, and mitochondrial membrane potential (MMP) with no significant effect on glutathione (GSH), catalase, glutathione reductase, glutathione peroxidase, and myeloperoxidase (MPO). In addition, lower reactivity (IRA) for glial fibrillary acidic protein (GFAP) as an index of astrocyte activity was observed and loss of CA1 pyramidal neurons was attenuated following sinomenine treatment. This study demonstrated that sinomenine could lessen TMT-induced cognitive dysfunction which is partly due to its attenuation of hippocampal oxidative stress and neuroinflammation.

Keap1 as Target of Genistein on Nrf2 Signaling Pathway Antagonizing Aβ induced Oxidative Damage of Cerebrovascular Endothelial Cells

BACKGROUND

β-amyloid peptides (Aβ) induced oxidative damage contributes to the pathogenesis of neurodegenerative diseases and cerebrovascular system is more vulnerable to oxidative stress. Our earlier study showed a clue that Genistein (Gen) might activate Nf-E2 related factor 2 (Nrf2) pathway to protect cerebrovascular cells from oxidative damage induced by Aβ, but the specific mechanisms and regulation targets are unclear.

OBJECTIVE

In this study, the anti-oxidative effects and the possible targets of Gen on regulating Nrf2 pathway in bEnd.3 cells were investigated. Cells were divided into control, Aβ25-35, Gen and Gen+Aβ25-35 groups.

METHODS

Cell viability, levels of malondialdehyde (MDA), Superoxide Dismutase (SOD) activity and nitrotyrosine were evaluated. Moreover, mRNA and/or protein expressions of Nrf2 and kelch-like ECH-associated protein 1 (Keap1) were measured. Then we transfected Keap1 over-expressed plasmid into bEnd.3 cells and measured the protein expressions of Nrf2 pathway related factors. Data showed that Gen could inhibit the over-production of MDA and nitrotyrosine and activate SOD activity. Besides we got the phenomenon that Gen could up-regulate the mRNA and protein expressions of Nrf2 and down-regulate Keap1 protein expression, the Keap1 over-expressed plasmid study indicated that the up-regulation of Nrf2 protein expression induced by pretreatment of Gen could be blocked by the transfection of Keap1 over-expressed plasmid, and the same results also occurred in Nrf2 downstream factors.

CONCLUSION

Gen could alleviate the cerebrovascular cells oxidative damage induced by Aβ25-35 through regulating Nrf2 pathway, and Keap1 might be one of the targets of Gen on activating Nrf2 pathway.

Paeonol Ameliorates Cuprizone-Induced Hippocampal Demyelination and Cognitive Deficits through Inhibition of Oxidative and Inflammatory Events

Multiple sclerosis (MS) is a chronic and inflammatory disorder of the central nervous system with autoimmune nature that is typified by varying degrees of demyelination and axonal damage. Paeonol is an active ingredient in some medicinal plants with anti-inflammatory and neuroprotective property. This study was conducted to reveal whether paeonol can alleviate hippocampal demyelination and cognitive deficits in cuprizone-induced murine model of demyelination as a model of MS. C57BL/6 mice received oral cuprizone (400 mg/kg) for 6 weeks, and paeonol was administered p.o. at two doses of 25 or 100 mg/kg, starting from the second week post-cuprizone for 5 weeks. After assessment of learning and memory in different tasks, oxidative stress and inflammation were evaluated besides immunohistochemical assessment of hippocampal myelin basic protein (MBP). Paeonol (100 mg/kg) properly ameliorated cognitive deficits in Y maze, novel object discrimination (NOD) test, and Barnes maze with no significant improvement of performance in passive avoidance task. In addition, paeonol treatment at the higher dose was also associated with partial restoration of hippocampal level of oxidative stress and inflammatory markers including MDA, ROS, GSH, SOD, catalase, NF-kB, and TNF. Besides, paeonol improved MMP as an index of mitochondrial integrity and health and reduced MPO as a factor of neutrophil infiltration. Furthermore, paeonol treatment prevented hippocampal MBP immunoreactivity, indicating its prevention of demyelination. In conclusion, the current study showed the preventive effect of paeonol against cuprizone-induced demyelination and cognitive deficits through reversing most oxidative stress- and inflammation-related parameters in addition to its improvement of mitochondrial health.

Neuroprotective mechanisms of red clover and soy isoflavones in Parkinson's disease models

Parkinson's disease (PD) is a neurodegenerative disorder characterized by nigrostriatal degeneration and the spreading of aggregated forms of the presynaptic protein α-synuclein (aSyn) throughout the brain. PD patients are currently only treated with symptomatic therapies, and strategies to slow or stop the progressive neurodegeneration underlying the disease's motor and cognitive symptoms are greatly needed. The time between the first neurobiochemical alterations and the initial presentation of symptoms is thought to span several years, and early neuroprotective dietary interventions could delay the disease onset or slow PD progression. In this study, we characterized the neuroprotective effects of isoflavones, a class of dietary polyphenols found in soy products and in the medicinal plant red clover (Trifolium pratense). We found that isoflavone-rich extracts and individual isoflavones rescued the loss of dopaminergic neurons and the shortening of neurites in primary mesencephalic cultures exposed to two PD-related insults, the environmental toxin rotenone and an adenovirus encoding the A53T aSyn mutant. The extracts and individual isoflavones also activated the Nrf2-mediated antioxidant response in astrocytes via a mechanism involving inhibition of the ubiquitin-proteasome system, and they alleviated deficits in mitochondrial respiration. Furthermore, an isoflavone-enriched soy extract reduced motor dysfunction exhibited by rats lesioned with the PD-related neurotoxin 6-OHDA. These findings suggest that plant-derived isoflavones could serve as dietary supplements to delay PD onset in at-risk individuals and mitigate neurodegeneration in the brains of patients.

Paeonol Ameliorates Cognitive Deficits in Streptozotocin Murine Model of Sporadic Alzheimer's Disease via Attenuation of Oxidative Stress, Inflammation, and Mitochondrial Dysfunction

Intracerebroventricular (ICV) microinjection of diabetogenic drug streptozotocin (STZ) in rodents consistently produces a model of sporadic Alzheimer's disease (sAD) which is characterized by tau pathology and concomitant cognitive decline, insulin resistance, neuroinflammation, oxidative stress, and mitochondrial malfunction. Paeonol is an active phenolic component in some medicinal plants like Cortex Moutan with neuroprotective efficacy via exerting anti-inflammatory and anti-oxidative effects. This study was conducted to assess beneficial effect of paeonol in amelioration of cognitive deficits in ICV STZ rat model of sAD. STZ (3 mg/kg) was microinjected into the lateral ventricles on days 0 and 2, and paeonol was given p.o. at two doses of 25 (low) or 100 (high) mg/kg from day 0 (post-surgery) till day 24 post-STZ. Cognitive performance was evaluated in different tasks, and oxidative stress- and inflammation-related parameters were measured in addition to immunohistochemical assessment of glial fibrillary acidic protein (GFAP) as a marker of astrocytes. Paeonol at the higher dose ameliorated cognitive deficits in Barnes maze, novel object recognition (NOR) task, Y maze, and passive avoidance test. In addition, paeonol partially reversed hippocampal malondialdehyde (MDA), reactive oxygen species (ROS), total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase, glutathione reductase, tumor necrosis factor α (TNFα), interleukin 6 (IL-6), mitochondrial membrane potential (MMP), myeloperoxidase (MPO), and acetylcholinesterase (AChE) activity. Paeonol treatment was also associated with lower hippocampal immunoreactivity for GFAP. This study showed that paeonol can alleviate cognitive disturbances in ICV STZ rat model of sAD via ameliorating neuroinflammation, oxidative stress, mitochondrial dysfunction, and also through its attenuation of astrogliosis.

Polyphenols and neuroprotection: Therapeutic implications for cognitive decline

Dietary polyphenols have been the focus of major interest for their potential benefits on human health. Several preclinical studies have been conducted to provide a rationale for their potential use as therapeutic agents in preventing or ameliorating cognitive decline. However, results from human studies are scarce and poorly documented. The aim of this review was to discuss the potential mechanisms involved in age-related cognitive decline or early stage cognitive impairment and current evidence from clinical human studies conducted on polyphenols and the aforementioned outcomes. The evidence published so far is encouraging but contrasting findings are to be taken into account. Most studies on anthocyanins showed a consistent positive effect on various cognitive aspects related to aging or early stages of cognitive impairment. Studies on cocoa flavanols, resveratrol, and isoflavones provided substantial contrasting results and further research is needed to clarify the therapeutic potential of these compounds. Results from other studies on quercetin, green tea flavanols, hydroxycinnamic acids (such as chlorogenic acid), curcumin, and olive oil tyrosol and derivatives are rather promising but still too few to provide any real conclusions. Future translational studies are needed to address issues related to dosage, optimal formulations to improve bioavailability, as well as better control for the overall diet, and correct target population.

Melatonin reverses cognitive deficits in streptozotocin-induced type 1 diabetes in the rat through attenuation of oxidative stress and inflammation

Uncontrolled diabetes mellitus (DM) is linked to attentional deficits and cognition deterioration. The neurohormone melatonin is an endogenous synchronizer of circadian rhythms with multiple protective properties. This research was designed to assess its effect against learning and memory decline in streptozotocin (STZ)-induced diabetic rats. Rats were assigned to control, melatonin-treated control, diabetic, and melatonin-treated diabetic groups. Melatonin was administered i.p. at a dose of 10 mg/kg/day for 47 days. Treatment of diabetic rats with melatonin reversed decline of spatial recognition memory in Y maze, performance of rats in novel object discrimination, and retention and recall in passive avoidance tasks. Furthermore, melatonin appropriately attenuated hippocampal malondialdehyde (MDA) and reactive oxygen species (ROS) and improved superoxide dismutase (SOD) activity and improved mitochondrial membrane potential (MMP) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) with no significant effect on nitrite, glutathione (GSH) and catalase activity. Besides, hippocampal level of acetylcholinesterase (AChE), glial fibrillary acidic protein (GFAP), nuclear factor-kappaB (NF-κB), interleukin 6 (IL-6) and tumor necrosis factor α (TNFα) decreased following melatonin treatment. There was also a reduction of dendritic spines of pyramidal neurons of hippocampal CA1 area in diabetic group that was significantly alleviated upon melatonin treatment. Melatonin could ameliorate learning and memory disturbances in diabetic rats through mitigation of cholinesterase activity, astrocytes, oxidative stress and inflammation and also via upregulation of some antioxidants in addition to its prevention of dendritic spine loss.

LongShengZhi Capsule Attenuates Alzheimer-Like Pathology in APP/PS1 Double Transgenic Mice by Reducing Neuronal Oxidative Stress and Inflammation

Alzheimer’s disease (AD) is the most common form of dementia in the elderly. It may be caused by oxidative stress, inflammation, and cerebrovascular dysfunctions in the brain. LongShengZhi Capsule (LSZ), a traditional Chinese medicine, has been approved by the China Food and Drug Administration for treatment of patients with cardiovascular/cerebrovascular disease. LSZ contains several neuroprotective ingredients, including Hirudo, Astmgali Radix, Carthami Flos (Honghua), Persicae Semen (Taoren), Acori Tatarinowii Rhizoma (Shichangpu), and Acanthopanax Senticosus (Ciwujia). In this study, we aimed to determine the effect of LSZ on the AD process. Double transgenic mice expressing the amyloid-β precursor protein and mutant human presenilin 1 (APP/PS1) to model AD were treated with LSZ for 7 months starting at 2 months of age. LSZ significantly improved the cognition of the mice without adverse effects, indicating its high degree of safety and efficacy after a long-term treatment. LSZ reduced AD biomarker Aβ plaque accumulation by inhibiting β-secretase and γ-secretase gene expression. LSZ also reduced p-Tau expression, cell death, and inflammation in the brain. Consistently, in vitro, LSZ ethanol extract enhanced neuronal viability by reducing L-glutamic acid-induced oxidative stress and inflammation in HT-22 cells. LSZ exerted antioxidative effects by enhancing superoxide dismutase and glutathione peroxidase expression, reduced Aβ accumulation by inhibiting β-secretase and γ-secretase mRNA expression, and decreased p-Tau level by inhibiting NF-κB-mediated inflammation. It also demonstrated neuroprotective effects by regulating the Fas cell surface death receptor/B-cell lymphoma 2/p53 pathway. Taken together, our study demonstrates the antioxidative stress, anti-inflammatory, and neuroprotective effects of LSZ in the AD-like pathological process and suggests it could be a potential medicine for AD treatment.

Diabetic Encephalopathy Affecting Mitochondria and Axonal Transport Proteins

Introduction

Diabetic encephalopathy is described as any cognitive and memory impairments associated with hippocampal degenerative changes, including the neurodegenerative process and decreased number of living cells. Mitochondrial diabetes (MD) appears following activation of mutant mitochondrial DNA and is a combination of diabetes and cognitive deficit. In this research, we showed the correlation of diabetic encephalopathy, dysfunctional mitochondria, and changes in the expression of axonal transport proteins (KIF5b, Dynein).

Methods

Twenty-four male Wistar rats were divided into three groups: (n=8 in each group):1. Control + saline; 2. Diabetic, and 3. Diabetic + insulin. Before starting the experiments, the animals with blood sugar lower than 150 mg/dL entered the study. Diabetes induction was carried out by Intraperitoneal (IP) Streptozotocin (STZ) administration. Fasting Blood Sugar (FBS) and body weight was checked after the first week and at the end of the eighth week. Then, behavioral studies (elevated plus maze, Y-maze, and passive avoidance learning) were performed. After behavioral studies, blood samples were taken to measure serum insulin level and HgbA1c. Next, fresh hippocampal tissue was collected. Gene expression of motor proteins was assessed by real-time PCR and mitochondrial membrane potential by rhodamine123.

Results

Our results showed the impairment of HgbA1c, serum insulin, FBS, and weight in the diabetic group (P<0.05). Behavioral tests revealed different degrees of impairment in diabetic rats (P<0.05). KIF5b mRNA expression increased in the hippocampus (P<0.05) with no change in dynein gene expression. These changes were associated with abnormal mitochondrial membrane potential (P<0.05).

Conclusion

KIF5b mRNA up-regulation in hippocampal neurons of STZ-diabetic rats is a factor that can be involved in abnormal axonal transport and decreased MMP, leading to impairment of mitochondrial function. These manifestations showed mitochondrial dysfunction in diabetes and resulted in abnormal behavioral tests and diabetic encephalopathy.

Bioenergetic signature as a target of zinc oxide nanoparticles in Ehrlich ascitic carcinoma-bearing mice

The current study aims to evaluate the modulatory effect of zinc oxide nanoparticles (ZnO NPs) on the bioenergetic signature biomarkers in the Ehrlich ascitic carcinoma (EAC) model. To achieve this goal, 90 female albino mice were included in this study and were divided into six equal groups (n   =15 per group): saline-treated group, ZnO NP-treated, EACs-bearing mice, and three groups of EACs-bearing mice treated with ZnO NPs at a dose of 20 mg/kg every other day, 10 mg/kg every other day, 10 mg/kg every day, respectively, for 14 days. The tissues from treated groups and control groups were homogenized and used for the assay of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and F1 beta subunit of adenosine triphosphate (ATP) synthase levels, as well as the determination of lactate level. The survival time of mice was improved in all ZnO NP-treated groups, especially in EACs-bearing mice treated with ZnO NPs at a dose of 10  mg/kg every other day. This improvement was associated with an increased F1 beta subunit of ATP synthase level and a decreased GAPDH level. Also, the lactate level was significantly decreased in all treated groups when compared with the untreated group. The overall effect was the increased bioenergetic signature as compared with EC.These results implied that ZnO NPs have a significant efficacy against cancer cells and they significantly increased the bioenergetic signature.

Safranal, an active ingredient of saffron, attenuates cognitive deficits in amyloid β-induced rat model of Alzheimer's disease: underlying mechanisms

Alzheimer's disease (AD) is the most prevalent neurodegenerative amyloid disorder with progressive deterioration of cognitive and memory skills. Despite many efforts, no decisive therapy yet exists for AD. Safranal is the active constituent of saffron essential oil with antioxidant, anti-inflammatory, and anti-apoptotic properties. In this study, the possible beneficial effect of safranal on cognitive deficits was evaluated in a rat model of AD induced by intrahippocampal amyloid beta (Aβ_1-40). Safranal was daily given p.o. (0.025, 0.1, and 0.2 ml/kg) post-surgery for 1 week and finally learning and memory were evaluated in addition to assessment of the involvement of oxidative stress, inflammation, and apoptosis. Findings showed that safranal treatment of amyloid β-microinjected rats dose-dependently improved cognition in Y-maze, novel-object discrimination, passive avoidance, and 8-arm radial arm maze tasks. Besides, safranal attenuated hippocampal level of malondialdehyde (MDA), reactive oxygen species (ROS), protein carbonyl, interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor α (TNFα), nuclear factor-kappa B (NF-kB), apoptotic biomarkers including caspase 3 and DNA fragmentation, glial fibrillary acidic protein (GFAP), myeloperoxidase (MPO), and acetylcholinesterase (AChE) activity and improved superoxide dismutase (SOD) activity and mitochondrial membrane potential (MMP) with no significant effect on nitrite, catalase activity, and glutathione (GSH). Furthermore, safranal prevented CA1 neuronal loss due to amyloid β_1-40. In summary, safranal treatment of intrahippocampal amyloid beta_1-40-microinjected rats could prevent learning and memory decline via neuronal protection and at a molecular level through amelioration of apoptosis, oxidative stress, inflammation, cholinesterase activity, neutrophil infiltration, and also by preservation of mitochondrial integrity.

Soybean isoflavone ameliorates cognitive impairment, neuroinflammation, and amyloid β accumulation in a rat model of Alzheimer's disease

Oxidative stress and neuroinflammatory changes appear to be the early events involved in AD's development and progression. The present study was designed to assess the effect of soybean isoflavone extract (SIFE) against colchicine-induced cognitive dysfunction and oxidative stress in male rats.Fifty adult male Wistar albino rats were divided into five groups: control, ACSF-treated group, soybean isoflavones (SIF)-treated group, colchicine (COL)-treated group, and SIF + COL-treated group. We found that an intracerebroventricular (icv) injection of a single dose of colchicine (7.5 μg/rat bilaterally) resulted in learning deficits in rats subjected to the Morris water maze task associated with marked oxidative damage and decreased acetyl cholinesterase (AChE) activity. In addition, COL caused significant increase in amyloid beta peptide 1-42 (β, amyloid 1-42) interleukin-1β (IL-1β), tumor necrosis factor-α (TNFα), cyclooxygenase-2 (COX-2) and TNF-α genes expression in the brain, and glial fibrillary acidic protein (GFAP) in cortical astrocytes in the brain cortex.Treatment with SIFE (80 mg/kg b.wt) daily for 14 days followed by a single dose of COL significantly reduced the elevated oxidative stress parameters and restored the reduced antioxidant activities. Besides, the administration of SIFE reversed the overproduction of β, amyloid 1-42, pro-inflammatory cytokines, and GFAP in the brain. The obtained results were confirmed by histological observations that clearly indicate a neuroprotective effect of SIF against AD.

Soy Isoflavones Improve the Spermatogenic Defects in Diet-Induced Obesity Rats through Nrf2/HO-1 Pathway

Soy isoflavones (SIF) are biologically active compounds of non-steroidal and phenolic properties that are richly present in soybeans, which can reduce the body weight and blood lipids of obese animals. Recently, SIF have been reported to affect reproductive ability in obese male rats. However, the specific mechanism has not been well defined. The aim of the current study was to study the possible mechanisms for the effect of SIF administration on obesity induced spermatogenic defects. Obese rats model induced by high-fat diets were established and gavage treated with 0, 50,150 or 450 mg of SIF/kg body weight/day for 4 weeks. Here, our research shows that obesity resulted in spermatogenic degeneration, imbalance of reproductive hormone, testicular oxidative stress and germ cell apoptosis, whereas evidently recovery effects were observed at 150 and 450 mg/kg SIF. We also have discovered that 150 and 450 mg/kg SIF can activate Nrf2/HO-1 pathway in control of Bcl-2, BAX and cleaved caspase-3 expression with implications in antioxidant protection. Our study indicates the potential mechanism of SIF regulating spermatogenic function in obese rats, and provides a scientific experimental basis for the regulation of biological function of obese male reproductive system by SIF.

Therapeutic potential of sodium selenite in letrozole induced polycystic ovary syndrome rat model: Targeting mitochondrial approach (selenium in PCOS)

Polycystic ovary syndrome (PCOS) is the most common endorinopathy in fertile women with heterogeneous reproductive and metabolic phenotypes and unknown etiology. This study was undertaken to investigate the beneficial effect of selenium in management of letrozole induced PCOS and its role in modulating mitochondrial dynamics, and its associated signals. Twenty four adult female rats were enrolled and randomly divided into four equal groups; control group received 0.5% w/v carboxymethyl cellulose (CMC); PCOS group received letrozole (1 mg/kg, daily) in 0.5% CMC for 21 days. From day 22 to day 36, after letrozole PCOS induction, the (PCOS +Metformin) group received metformin (2 mg/kg, daily) while (PCOS + sodium selenite) group received sodium selenite (0.1 mg/kg, daily). All doses were given via oral gavage. At the study end, serum hormone levels, lipid profile and HOMA-IR were assessed. Ovaries were dissected, used for histopathological evaluation, immunohistochemical detection of B-cell lymphoma-2 (Bcl-2), and its associated X protein (Bax) expression, measurement of redox status, mitochondrial dynamics markers and citrate synthase (CS) activity. Furthermore Mitofusins 2 (Mfn2) and dynamin related protein 1 (Drp1) mRNA expression was assessed by real time PCR. Selenium treatment of PCOS rats succeeded, comparable to metformin, to greatly improve the PCOS associated endocrine and metabolic phenotypes and histopathological changes, mostly through modulating mitochondrial dynamics, anti-apoptotic action, alleviating oxidative stress and mitochondrial dysfunction. So, selenium could provide a novel therapeutic strategy for PCOS.

Trigonelline protects hippocampus against intracerebral Aβ(1-40) as a model of Alzheimer's disease in the rat: insights into underlying mechanisms

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most common phenotype of dementia. Trigonelline is an alkaloid found in medicinal plants such as fenugreek seeds and coffee beans with neuroprotective potential and according to existing evidences, a favorable agent for treatment of neurodegenerative disorders. In this study, the possible protective effect of trigonelline against intracerebral Aβ(1-40) as a model of AD in the rat was investigated. For induction of AD, aggregated A(1-40) (10 μg/2 휇l for each side) was bilaterally microinjected into the hippocampal CA1 area. Trigonelline was administered p.o. at a dose of 100 mg/kg. The results showed that trigonelline pretreatment of Aβ-microinjected rats significantly improves spatial recognition memory in Y maze and performance in novel object recognition (NOR) task, mitigates hippocampal malondialdehyde (MDA), protein carbonyl, lactate dehydrogenase (LDH), and improves mitochondrial membrane potential (MMP), glutathione (GSH), and superoxide dismutase (SOD) with no significant change of catalase activity, nitrite level, caspase 3 activity, and DNA fragmentation. Additionally, trigonelline ameliorated hippocampal levels of glial fibrillary acidic protein (GFAP), S100b, cyclooxygenase 2 (Cox2), tumor necrosis factor α (TNFα), and interleukin 6 (IL-6) with no significant alteration of inducible nitric oxide synthase (iNOS). In addition, trigonelline pretreatment prevented loss of hippocampal CA1 neurons in Aβ-microinjected group. Therefore, our results suggest that trigonelline pretreatment in Aβ model of AD could improve cognition and is capable to alleviate neuronal loss through suppressing oxidative stress, astrocyte activity, and inflammation and also through preservation of mitochondrial integrity.

Genistein Ameliorates Scopolamine-Induced Amnesia in Mice Through the Regulation of the Cholinergic Neurotransmission, Antioxidant System and the ERK/CREB/BDNF Signaling

Genistein (GE) was reported to exert a wide spectrum of biological activities, including antioxidant, anti-inflammatory, anti-mutagenic, anticancer, and cardio-protective effects. In addition, both clinical and preclinical studies have recently suggested GE a potential neuroprotective and memory-enhancing drug against neurodegenerative diseases. The animal model of scopolamine (Scop)-induced amnesia is widely used to study underlying mechanisms and treatment of cognitive impairment in neurodegenerative diseases. However, there is no report about the effects of GE on Scop-induced amnesia in mice. Therefore, the present study was carried out to investigate the beneficial effects and potential mechanism of GE against Scop-induced deficits in mice. The mice were orally pretreated with either GE (10, 20, and 40 mg/kg) or donepezil (1.60 mg/kg) for 14 days. After the pretreatment, the open field test was conducted to assess the effect of GE on the locomotor activity of mice. Thereafter, mice were daily injected with Scop (0.75 mg/kg) intraperitoneally to induce memory deficits and subjected to the cognitive behavioral tests including the Object Location Recognition (OLR) experiment and Morris Water Maze (MWM) task. After the behavioral tests, biochemical parameter assay and western blot analysis were used to examine the underlying mechanisms of its action. The results showed that GE administration significantly improved the cognitive performance of Scop-treated mice in OLR and Morris water maze tests, exerting the memory-enhancing effects. Additionally, GE remarkably promoted the cholinergic neurotransmission and protected against the oxidative stress damage in the hippocampus of Scop-treated mice, as indicated by decreasing AChE activity, elevating ChAT activity and Ach level, increasing SOD activity, lowering the level of MDA and increasing GSH content. Furthermore, GE was found to significantly upregulate the expression levels of p-ERK, p-CREB and BDNF proteins in the hippocampus of Scop-treated mice. Taken together, these results for the first time found that GE exerts cognitive-improving effects in Scop-induced amnesia and suggested it may be a potential candidate compound for the treatment of some neurodegenerative diseases such as Alzheimer's Disease (AD).

Hesperetin, a citrus flavonoid, attenuates testicular damage in diabetic rats via inhibition of oxidative stress, inflammation, and apoptosis

AIM

This study was designed to assess the beneficial effect of hesperetin on diabetes-associated testicular injury in the rat.

MAIN METHODS

Oral treatment with hesperetin started 10 days after diabetes induction by streptozotocin (60 mg/kg, i.p.) for 46 days. Testicular damage was evaluated by histological evaluation of seminiferous tubules in addition to assessment of epididymal sperm count, motility, and viability. In addition, testicular biomarkers of apoptosis, inflammation, and oxidative stress were also determined.

KEY FINDINGS

Hesperetin treatment of diabetic group prevented body weight loss and reduced serum glucose in addition to improvement of serum testosterone. Additionally, hesperetin-treated diabetic group had lower levels of malondialdehyde (MDA), reactive oxygen species (ROS), protein carbonyl, DNA fragmentation, and caspase 3 activity as specific biomarkers of oxidative stress and/or apoptosis. Furthermore, hesperetin augmented testicular antioxidant system as shown by higher levels of glutathione (GSH), mitochondrial membrane potential (MMP), and ferric reducing antioxidant power (FRAP) in addition to improvement of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx). Moreover, hesperetin administration to diabetic rats attenuated testicular indices of inflammation consisting of tumor necrosis factor α (TNFα) and interleukin 17 (IL-17) and prevented damage of seminiferous tubules as revealed by higher levels of sperm count, motility, and viability in diabetic rats.

SIGNIFICANCE

Collectively, hesperetin could alleviate testicular damage in DM, at least through inhibition of apoptosis, oxidative stress, and inflammation in addition to its up-regulation of endogenous enzymatic and non-enzymatic antioxidants.

Protective Effect of Genistein against Neuronal Degeneration in ApoE-/- Mice Fed a High-Fat Diet

Altered cholesterol metabolism is believed to play a causal role in major pathophysiological changes in neurodegeneration. Several studies have demonstrated that the absence of apolipoprotein E (ApoE), a predominant apolipoprotein in the brain, leads to an increased susceptibility to neurodegeneration. Previously, we observed that genistein, a soy isoflavone, significantly alleviated apoptosis and tau hyperphosphorylation in SH-SY5Y cells. Therefore, we investigated the neuroprotective effects of dietary genistein supplementation (0.5 g/kg diet) in the cortex and hippocampus of wild-type C57BL/6 (WT) and ApoE knockout (ApoE^−/−) mice fed a high-fat diet (HFD) for 24 weeks. Genistein supplementation alleviated neuroinflammation and peripheral and brain insulin resistance. Reductions in oxidative and endoplasmic reticulum stress were also observed in ApoE^−/− mice fed a genistein-supplemented diet. Beta-secretase 1 and presenilin 1 mRNA levels and beta-amyloid peptide (Aβ) protein levels were reduced in response to genistein supplementation in ApoE^−/− mice but not in WT mice. Although the absence of ApoE did not increase tau hyperphosphorylation, genistein supplementation reduced tau hyperphosphorylation in both WT and ApoE^−/− mice. Consistent with this result, we also observed that genistein alleviated activity of c-Jun N-terminal kinase and glycogen synthase kinase 3β, which are involved in tau hyperphosphorylation. Taken together, these results demonstrate that genistein alleviated neuroinflammation, Aβ deposition, and hyperphosphorylation in ApoE^−/− mice fed an HFD.

HO-1 Signaling Activation by Pterostilbene Treatment Attenuates Mitochondrial Oxidative Damage Induced by Cerebral Ischemia Reperfusion Injury

Ischemia reperfusion (IR) injury (IRI) is harmful to the cerebral system and causes mitochondrial oxidative stress. The antioxidant response element (ARE)-mediated antioxidant pathway plays an important role in maintaining the redox status of the brain. Heme oxygenase-1 (HO-1), combined with potent AREs in the promoter of HO-1, is a highly effective therapeutic target for protection against cerebral IRI. Pterostilbene (PTE), a natural dimethylated analog of resveratrol from blueberries, is a strong natural antioxidant. PTE has been shown to be beneficial for some nervous system diseases and may regulate HO-1 signaling. This study was designed to investigate the protective effects of PTE on cerebral IRI and to elucidate potential mechanisms underlying those effects. Mouse brains and cultured HT22 neuron cells were subjected to IRI. Prior to this procedure, the brains or cells were exposed to PTE in the absence or presence of the HO-1 inhibitor ZnPP or HO-1 small interfering RNA (siRNA). PTE conferred a cerebral protective effect, as shown by increased neurological scores, viable neurons and decreased brain edema as well as a decreased ion content and apoptotic ratio in vivo. PTE also increased the cell viability and decreased the lactate dehydrogenase (LDH) leakage and apoptotic ratio in vitro. ZnPP and HO-1 siRNA both blocked PTE-mediated cerebral protection by inhibiting HO-1 signaling and further inhibited two HO-1 signaling-related antioxidant molecules:

NAD(P)H

quinone oxidoreductase 1 (NQO1) and glutathione S-transferases (GSTs), which are induced by PTE. PTE also promoted a well-preserved mitochondrial membrane potential (MMP), mitochondria complex I activity, and mitochondria complex IV activity, increased the mitochondrial cytochrome c level, and decreased the cytosolic cytochrome c level. However, this PTE-elevated mitochondrial function was reversed by ZnPP or HO-1 siRNA treatment. In summary, our results demonstrate that PTE treatment attenuates cerebral IRI by reducing IR-induced mitochondrial oxidative damage through the activation of HO-1 signaling.

Mitochondrial dysfunction and oxidative damage in the brain of diet-induced obese rats but not in diet-resistant rats

AIMS

It has been suggested that obesity triggered by consuming a high-fat diet (HF) can account for oxidative damage and mitochondrial dysfunction. Thus, we aim to explore the oxidative stress and mitochondrial dysfunction detected in the brain of diet-induced obese (DIO) rats.

MAIN METHODS

Sprague-Dawley (SD) rats were fed either a HF diet or a normal-fat (NF) diet for 10weeks to obtain the control (CON), DIO and diet-resistant (DR) rats. d-Galactose was injected subcutaneously for 10weeks to establish oxidative stress model (MOD) rats. Then, the levels of total antioxidant capacity (T-AOC), lipid peroxidation (LPO), malondialdehyde (MDA), both in plasma and brain tissue, and catalase (CAT) in plasma were measured using enzymic assay kits and the levels of ghrelin, neuropeptide Y (NPY) and leptin in both plasma and brain tissue were measured by using enzyme-linked immunosorbent assay (ELISA) kits. Mitochondrial reactive oxygen species (ROS) formation in brain tissues was detected with 2, 7-dichlorofluorescein diacetate (DCFH2-DA) dyeing. The mitochondrial membrane potential (MMP) was measured with tetrachloro-tetraethyl benzimidazol carbocyanine iodide (JC-1) by a flow cytometer.

KEY FINDINGS

HF diet leads to an obese or DR state characterized by increased or decreased adiposity. The HF diet increased brain LPO, which was accompanied by lower ghrelin levels in DIO rats compared with DR rats. In addition, the increased mitochondrial ROS and lower MMP were detected in DIO rat comparing with DR rats.

SIGNIFICANCE

The current results demonstrated that mitochondrial dysfunction and oxidative damage in the brains of DIO rats, induced by HF diets, might be measurable.

Soy isoflavone antagonizes the oxidative cerebrovascular injury induced by β-amyloid peptides 1-42 in rats

Numerous evidences have shown that the antioxidative properties of soy isoflavone (SIF) have beneficial effects on prophylaxis of neurodegeneration, however, the mechanism is still not fully illustrated. As cerebrovascular dysfunction could initiate a cascade of events leading to pathogenesis of Alzheimer's disease, we tried to investigate whether SIF could protect the cerebrovascular system due to antagonizing oxidative damage induced by Aβ1-42 in present study. In addition, NF-E2-related factor 2 (Nrf2) signaling pathways in the cerebrovascular tissue of Wistar rats were investigated to identify the potential cerebrovascular protective targets of SIF. Research results showed that SIF reduced the excessive production of nitrotyrosine in cerebrovascular tissue induced by Aβ1-42, and maintained redox homeostasis by increasing the level of GSH and GSH/GSSG. Moreover, SIF could alleviate the down-regulation of Nrf2, γ-glutamylcysteine synthetase, Heme oxygenase-1 expressions in cerebrovascular tissue induced by Aβ1-42 and suppress the increase of Kelch like ECH protein-1 (Keap1). These data suggested that SIF might reduce the cerebrovascular oxidative damage induced by Aβ1-42 through regulating the Nrf2 signaling pathway. The mechanisms of SIF modulating the potential target Nrf2 might be associated with Keap1 expression.

Soybean isoflavone ameliorates β-amyloid 1-42-induced learning and memory deficit in rats by protecting synaptic structure and function

This research aims to investigate whether soybean isoflavone (SIF) could alleviate the learning and memory deficit induced by β-amyloid peptides 1-42 (Aβ 1-42) by protecting the synapses of rats. Adult male Wistar rats were randomly allocated to the following groups: (1) control group; (2) Aβ 1-42 group; (3) SIF group; (4) SIF + Aβ 1-42 group (SIF pretreatment group) according to body weight. The 80 mg/kg/day of SIF was administered orally by gavage to the rats in SIF and SIF+Aβ 1-42 groups. Aβ 1-42 was injected into the lateral cerebral ventricle of rats in Aβ 1-42 and SIF+Aβ 1-42 groups. The ability of learning and memory, ultramicrostructure of hippocampal synapses, and expression of synaptic related proteins were investigated. The Morris water maze results showed the escape latency and total distance were decreased in the rats of SIF pretreatment group compared to the rats in Aβ1-42 group. Furthermore, SIF pretreatment could alleviate the synaptic structural damage and antagonize the down-regulation expressions of below proteins induced by Aβ1-42: (1) mRNA and protein of the synaptophysin and postsynaptic density protein 95 (PSD-95); (2) protein of calmodulin (CaM), Ca(2+) /calmodulin-dependent protein kinase II (CaMK II), and cAMP response element binding protein (CREB); (3) phosphorylation levels of CaMK II and CREB (pCAMK II, pCREB). These results suggested that SIF pretreatment could ameliorate the impairment of learning and memory ability in rats induced by Aβ 1-42, and its mechanism might be associated with the protection of synaptic plasticity by improving the synaptic structure and regulating the synaptic related proteins.