Metformin Alleviated the Neuronal Oxidative Stress in Hippocampus of Rats under Single Prolonged Stress

Nutritional Support of Crocin on Neurobehavioral Disabilities Induced by Cisplatin-Based Chemotherapy in Rats

Cisplatin, a chemotherapy drug containing platinum, is considered a neurotoxic agent. On the other hand, crocin, the primary component of saffron, possesses neuroprotective and antioxidant properties. In this study, 28 healthy adult male Wistar rats weighing 200-250 g were used (6-7 weeks old). Rats were divided into a control group (Ctr), a crocin group (Cro), a cisplatin group (Cis), and a crocin with cisplatin group (Cro + Cis). Rotarod, open field, and shuttle box tests were performed to assess balance, explorative behavior, and avoidance memory. After behavioral testing, the hippocampus was extracted to analyze oxidative stress parameters such as GPx (glutathione peroxidase), SOD (superoxide dismutase), CAT (catalase), and MDA (malondialdehyde) activity. Shuttle box, rotarod, and open field results showed that crocin can substantially mitigate the deleterious effects of cisplatin on avoidance memory, explorative behavior, motor coordination, and balance. Crocin was also able to effectively avoid the negative effects of cisplatin on MDA, GPx, and CAT during the assessment of oxidative indicators, while the beneficial effect of crocin on cisplatin was not statistically significant in terms of SOD level. In conclusion, since free radicals produced by cisplatin are a contributing factor to memory loss and movement disorders, crocin, owing to its antioxidant properties, improved passive avoidance learning as well as motor activity.

Behavioral stress and antidepressant treatments altered hippocampal expression of Nogo signal-related proteins in rats

Some immune molecules including neurite outgrowth inhibitor (Nogo) ligands and their receptor（Nogo receptor-1: NgR1）are expressed at the neuronal synaptic sites. Paired immunoglobulin-like receptor B (PirB) is another Nogo receptor that also binds to major histocompatibility complex I and β-amyloid and suppresses dendritic immune cell functions and neuronal plasticity in the central nervous system. Augmenting structural and functional neural plasticity by manipulating the Nogo signaling pathway is a novel promising strategy for treating brain ischemia and degenerative processes such as Alzheimer's disease. In recent decades psychiatric research using experimental animals has focused on the attenuation of neural plasticity by stress loadings and on the enhanced resilience by psychopharmacological treatments. In the present study, we examined possible expressional alterations in Nogo signal-related proteins in the rat hippocampus after behavioral stress loadings and antidepressant treatments. To validate the effectiveness of the procedures, previously reported increase in brain-derived neurotrophic factor (BDNF) by ECS or ketamine administration and decrease of BDNF by stress loadings are also shown in the present study. Significant increases in hippocampal NgR1 and PirB expression were observed following chronic variable stress, and a significant increase in NgR1 expression was observed under a single prolonged stress paradigm. These results indicate a possible contribution of enhanced Nogo signaling to the attenuation of neural plasticity in response to stressful experiences. Additionally, the suppression of hippocampal NgR1 expression using electroconvulsive seizure treatment and administration of subanesthetic dose of ketamine supported the increased neural plasticity induced by the antidepressant treatments.

Metformin attenuates sevoflurane-induced neurogenesis damage and cognitive impairment: involvement of the Nrf2/G6PD pathway

Anesthetics such as sevoflurane are commonly administered to infants and children. However, the possible neurotoxicity caused by prolonged or repetitive exposure to it should be a concern. The neuroprotective effects of metformin are observed in many models of neurological disorders. In this study, we investigated whether metformin could reduce the developmental neurotoxicity induced by sevoflurane exposure in neonatal rats and the potential mechanism. Postnatal day 7 (PND 7) Sprague-Dawley rats and neural stem cells (NSCs) were treated with normal saline or metformin before sevoflurane exposure. The Morris water maze (MWM) was used to observe spatial memory and learning at PND 35-42. Immunofluorescence staining was used to detect neurogenesis in the subventricular zone (SVZ) of the lateral ventricle and the subgranular zone (SGZ) of the dentate gyrus at PND 14. MTT assays, immunofluorescence staining, and TUNEL staining were used to assess the viability, proliferation, differentiation, and apoptosis of NSCs. Western blotting and ELISA were used to assess the protein expression of cleaved caspase-3, nuclear factor erythroid 2-related factor 2 (Nrf2), and glucose-6-phosphate dehydrogenase (G6PD) pathway-related molecules. Exposure to sevoflurane resulted in late cognitive defects, impaired neurogenesis in both the SVZ and SGZ, reduced NSC viability and proliferation, increased NSC apoptosis, and decreased protein expression of G6PD in vitro. Metformin pretreatment attenuated sevoflurane-induced cognitive functional decline and neurogenesis inhibition. Metformin pretreatment also increased the protein expression of Nrf2 and G6PD. However, treatment with the Nrf2 inhibitor, ML385 or the G6PD inhibitor, dehydroepiandrosterone (DHEA) reversed the protective effect of metformin on sevoflurane-induced NSC damage in vitro. Our findings suggested that metformin could reduce sevoflurane-induced neurogenesis damage and neurocognitive defects in the developing rat brain by influencing the Nrf2/G6PD signaling pathways.

A prognostic study on the effect of post-traumatic stress disorder on cerebral ischaemia reperfusion-induced stroke

OBJECTIVES

Previous studies have been established that persons who experienced a stroke are soon likely to develop several anxiety disorders. In which one of the major anxiety disorders is Post-traumatic Stress Disorder (PTSD). Yet, the likelihood of PTSD in conjunction with cerebral stroke has not been well described. Hence, we evaluated the impact of PTSD on cerebral stroke in rodents subjected to single prolonged stress (SPS) and bilateral common carotid artery occlusion (BCCAo), respectively.

METHODS

The relation between PTSD and cerebral stroke is evaluated by performing behavioural, biochemical, histopathological, and brain lesion area measurement studies.

RESULTS

Interestingly, SPS + BCCAo induction increased behavioural abnormalities like cognitive impairment and anxiety-like behaviour compared to SPS and BCCAo groups alone. Motor impairment was also observed in SPS + BCCAo rats compared to SPS rats, whereas no change with BCCAo rats. Furthermore, increased brain tissue MDA, acetylcholinesterase, and decreased SOD, catalase, and GSH were observed in SPS + BCCAo subjected rats compared to SPS and BCCAo rats alone. Additionally, SPS + BCCAo induction considerably increased the plasma corticosterone levels and caused severe neurotransmitter alterations. The SPS + BCCAo exposure significantly increased the brain lesion area in comparison with BCCAo rats. Moreover, severe histopathological alterations were observed in the hippocampus (CA1) of SPS + BCCAo rats compared to SPS and BCCAo rats alone.

CONCLUSIONS

In conclusion, our study results suggested that SPS-induced PTSD may aggravate the BCCAo induced cerebral ischaemia-reperfusion injury.

Metformin protects against inflammation, oxidative stress to delay poly I:C-induced aging-like phenomena in gut of an annual fish

Metformin, a clinical agent of type 2 diabetes, is reported as a potential geroprotector. Viral infection induces phenotypes of senescence in human T cells, and polyinosinic:polycytidylic acid (poly I:C), a viral mimic, induces upregulation of SA-β-gal activity in ovary of the annual fish Nothobranchius guentheri. However, the effects and mechanisms of metformin on poly I:C-induced aging-like phenomena are poorly understood in vertebrates. In this study, the activity of SA-β-gal increased in gut of 12-month-old fish and poly I:C-injected 6-month-old fish, compared to 6-month-old control fish, indicating that poly I:C induces aging-like phenomena in gut of the fish. Metformin supplementation retarded accumulation of SA-β-gal in gut of old fish and poly I:C-treated young fish. The results of q-PCR analysis showed that metformin reduced NF-κB mediated inflammatory response including decreased level of pro-inflammatory cytokine IL-8 and increased expression of anti-inflammatory cytokine IL-10 in gut of the fish with natural aging and poly I:C-injected 6-month-old fish. Metformin also exhibited antioxidant effects, as it reduced ROS production which is associated with the upregulation of FoxO3a and PGC-1α in gut of 6-month-old fish with poly I:C-injection. Expression of AMPK and SIRT1 was reduced in gut of 6-month-old fish with poly I:C-treatment, and feeding metformin reversed these declines. Taken together, the present study suggested that poly I:C-injection led to aging-like phenomena in gut and metformin activated AMPK and SIRT1 to reduce NF-κB mediated inflammation and resist oxidative stress via enhanced expression of FoxO3a and PGC-1α, and finally delayed gut aging in vertebrates.

Neurological & psychological aspects of Barth syndrome: Clinical manifestations and potential pathogenic mechanisms

Barth syndrome is a rare X-linked multisystem mitochondrial disease that is caused by variants in the tafazzin gene leading to deficient and abnormal cardiolipin. Previous research has focused on the cardiomyopathy and neutropenia in individuals with Barth syndrome, yet just as common are the least explored neurological aspects of Barth syndrome. This review focuses on the major neuropsychological and neurophysiological phenotypes that affect the quality of life of individuals with Barth syndrome, including difficulties in sensory perception and feeding, fatigue, and cognitive and psychological challenges. We propose selected pathogenetic mechanisms underlying these phenotypes and draw parallels to other relevant disorders. Finally, avenues for future research are also suggested.

Using Monozygotic Twins to Dissect Common Genes in Posttraumatic Stress Disorder and Migraine

Epigenetic mechanisms have been associated with genes involved in Posttraumatic stress disorder (PTSD). PTSD often co-occurs with other health conditions such as depression, cardiovascular disorder and respiratory illnesses. PTSD and migraine have previously been reported to be symptomatically positively correlated with each other, but little is known about the genes involved. The aim of this study was to understand the comorbidity between PTSD and migraine using a monozygotic twin disease discordant study design in six pairs of monozygotic twins discordant for PTSD and 15 pairs of monozygotic twins discordant for migraine. DNA from peripheral blood was run on Illumina EPIC arrays and analyzed. Multiple testing correction was performed using the Bonferroni method and 10% false discovery rate (FDR). We validated 11 candidate genes previously associated with PTSD including DOCK2, DICER1, and ADCYAP1. In the epigenome-wide scan, seven novel CpGs were significantly associated with PTSD within/near IL37, WNT3, ADNP2, HTT, SLFN11, and NQO2, with all CpGs except the IL37 CpG hypermethylated in PTSD. These results were significantly enriched for genes whose DNA methylation was previously associated with migraine (p-value = 0.036). At 10% FDR, 132 CpGs in 99 genes associated with PTSD were also associated with migraine in the migraine twin samples. Genes associated with PTSD were overrepresented in vascular smooth muscle, axon guidance and oxytocin signaling pathways, while genes associated with both PTSD and migraine were enriched for AMPK signaling and longevity regulating pathways. In conclusion, these results suggest that common genes and pathways are likely involved in PTSD and migraine, explaining at least in part the co-morbidity between the two disorders.

Oxidative Dysregulation in Early Life Stress and Posttraumatic Stress Disorder: A Comprehensive Review

Traumatic stress may chronically affect master homeostatic systems at the crossroads of peripheral and central susceptibility pathways and lead to the biological embedment of trauma-related allostatic trajectories through neurobiological alterations even decades later. Lately, there has been an exponential knowledge growth concerning the effect of traumatic stress on oxidative components and redox-state homeostasis. This extensive review encompasses a detailed description of the oxidative cascade components along with their physiological and pathophysiological functions and a systematic presentation of both preclinical and clinical, genetic and epigenetic human findings on trauma-related oxidative stress (OXS), followed by a substantial synthesis of the involved oxidative cascades into specific and functional, trauma-related pathways. The bulk of the evidence suggests an imbalance of pro-/anti-oxidative mechanisms under conditions of traumatic stress, respectively leading to a systemic oxidative dysregulation accompanied by toxic oxidation byproducts. Yet, there is substantial heterogeneity in findings probably relative to confounding, trauma-related parameters, as well as to the equivocal directionality of not only the involved oxidative mechanisms but other homeostatic ones. Accordingly, we also discuss the trauma-related OXS findings within the broader spectrum of systemic interactions with other major influencing systems, such as inflammation, the hypothalamic-pituitary-adrenal axis, and the circadian system. We intend to demonstrate the inherent complexity of all the systems involved, but also put forth associated caveats in the implementation and interpretation of OXS findings in trauma-related research and promote their comprehension within a broader context.

Metformin protects against PM2.5-induced lung injury and cardiac dysfunction independent of AMP-activated protein kinase α2

Fine particulate matter (PM_2.5) airborne pollution increases the risk of respiratory and cardiovascular diseases. Although metformin is a well-known antidiabetic drug, it also confers protection against a series of diseases through the activation of AMP-activated protein kinase (AMPK). However, whether metformin affects PM_2.5-induced adverse health effects has not been investigated. In this study, we exposed wild-type (WT) and AMPKα2^−/− mice to PM_2.5 every other day via intratracheal instillation for 4 weeks. After PM_2.5 exposure, the AMPKα2^−/− mice developed more severe lung injury and cardiac dysfunction than were developed in the WT mice; however the administration of metformin was effective in attenuating PM_2.5-induced lung injury and cardiac dysfunction in both the WT and AMPKα2^−/− mice. In the PM_2.5-exposed mice, metformin treatment resulted in reduced systemic and pulmonary inflammation, preserved left ventricular ejection fraction, suppressed induction of pulmonary and myocardial fibrosis and oxidative stress, and increased levels of mitochondrial antioxidant enzymes. Moreover, pretreatment with metformin significantly attenuated PM_2.5-induced cell death and oxidative stress in control and AMPKα2-depleted BEAS-2B and H9C2 cells, and was associated with preserved expression of mitochondrial antioxidant enzymes. These data support the notion that metformin protects against PM_2.5-induced adverse health effects through a pathway that appears independent of AMPKα2. Our findings suggest that metformin may also be a novel drug for therapies that treat air pollution associated disease.

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Metformin protects against PM_2.5 exposure-induced lung injury and cardiac dysfunction.

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Metformin alleviates PM_2.5-induced oxidative stress by regulating mitochondrial antioxidant enzymes.

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Metformin attenuates PM_2.5-induced cell death and oxidative stress in BEAS-2B and H9C2 cells.

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Metformin confers protection in an AMPKα2 independent manner.

Diosgenin ameliorates palmitic acid-induced lipid accumulation via AMPK/ACC/CPT-1A and SREBP-1c/FAS signaling pathways in LO2 cells

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is characterized by excessive hepatic lipid accumulation. Many studies have suggested that lipid overload is the key initial factor that contributes to hepatic steatosis. Our previous study indicated that diosgenin (DSG) has a beneficial effect on energy metabolism, but the underlying mechanism remains unclear.

METHODS

Human normal hepatocytes (LO2 cells) were incubated with palmitic acid to establish the cell model of nonalcoholic fatty liver. The effects of DSG on lipid metabolism, glucose uptake and mitochondrial function were evaluated. Furthermore, the mechanism of DSG on oxidative stress, lipid consumption and lipid synthesis in LO2 cells was investigated.

RESULTS

The results indicated that palmitic acid induced obvious lipid accumulation in LO2 cells and that DSG treatment significantly reduced the intracellular lipid content. DSG treatment upregulated expression of lipolysis proteins, including phospho-AMP activated protein kinase (p-AMPK), phospho-acetyl-coA carboxylase (p-ACC) and carnitine acyl transferase 1A (CPT-1A), and inhibited expression of lipid synthesis-related proteins, including sterol regulatory element-binding protein 1c (SREBP-1c) and fatty acid synthase (FAS). Additionally, DSG-treated cells displayed a marked improvement in mitochondrial function, with less production of reactive oxygen species and a higher mitochondrial membrane potential compared with the model group.

CONCLUSION

This study suggests that DSG can reduce intracellular lipid accumulation in LO2 cells and that the underlying mechanism may be related to the improving oxidative stress, increasing fatty acid β-oxidation and decreasing lipid synthesis. The above changes might be mediated by the activation of the AMPK/ACC/CPT-1A pathway and inhibition of the SREBP-1c/FAS pathway.

The beneficial roles of metformin on the brain with cerebral ischaemia/reperfusion injury

Cerebral ischaemia/reperfusion (I/R) injury is the transient loss, followed by rapid return, of blood flow to the brain. This condition is often caused by strokes and heart attacks. The underlying mechanisms resulting in brain damage during cerebral I/R injury include mitochondrial dysregulation, increased oxidative stress/reactive oxygen species, blood-brain-barrier breakdown, inflammation of the brain, and increased neuronal apoptosis. Metformin is the first-line antidiabetic drug which has recently been shown to be capable of acting through the aforementioned pathways to improve recovery following cerebral I/R injury. However, some studies have suggested that metformin therapy may have no effect or even worsen recovery following cerebral I/R injury. The present review will compile and examine the available in vivo, in vitro, and clinical data concerning the neuroprotective effects of metformin following cerebral I/R injury. Any contradictory evidence will also be assessed and presented to determine the actual effectiveness of metformin treatment in stroke recovery.

Role of apoptosis in the Post-traumatic stress disorder model-single prolonged stressed rats

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder which occurs following exposure to traumatic events. A number of brain neuroimaging studies have revealed that PTSD patients have reduced volume and abnormal functions in the hippocampus and the amygdala. However, the pathogenesis of abnormalities in certain brain regions, as induced by PTSD, remains unclear. Recent studies, using the single prolonged stress (SPS) model, an animal model of PTSD, have found that abnormal apoptosis in certain brain regions, including the hippocampus, the amygdala, and the medial prefrontal cortex (mPFC); these areas are closely associated with emotion and cognition. In this review, we summarize the mechanism of apoptosis in SPS rats, including the endoplasmic reticulum (ER) and the mitochondria pathways. For the ER pathway, three individual pathways: PERK, IRE1, and ATF6 showed different roles on apoptosis and neuroprotection. Three key factors are thought to be involved in the mitochondrial pathway and PTSD-induced apoptosis: corticosteroid receptors, apoptosis-related factors, and anti-apoptosis factors. We have investigated the role of these factors and have attempted to identify which factors of the pathways are more focused towards neuronal protection, and which are more direct towards apoptosis. We also discussed the role of autophagy and the specific differences between autophagy and apoptosis in SPS rats. Finally, we discussed emerging researches related to anti-apoptosis treatment, including PERK inhibitors, IRE1 inhibitors, and metformin; collectively, these were exciting, but limited, This review provides a summary of the current understanding of apoptosis in SPS rats and the potential anti-apoptosis treatment strategies for PTSD.