Influence of age, exercise, and dietary restriction on oxidative stress in rats

Responsiveness of respiratory function in Parkinson's Disease to an integrative exercise programme: A prospective cohort study

INTRODUCTION

Respiratory disorders are the most common cause of death in Parkinson's Disease (PD). Conflicting data exist on the aetiology of respiratory dysfunction in PD and few studies examine the effects of exercise-based interventions on respiratory measures. This study was conducted to better understand respiratory dysfunction in PD and to identify measures of dysfunction responsive to an integrative exercise programme.

OBJECTIVES

The objectives were to compare baseline respiratory measures with matched, published population norms and to examine immediate and longer-term effects of a 12-week integrated exercise programme on these measures.

DESIGN

Twenty-three people with mild PD (median Hoehn & Yahr = 2) self-selected to participate in this exploratory prospective cohort study. Evaluation of participants occurred at three time points: at baseline; following the 12-week exercise programme and at 4-month follow-up.

OUTCOME MEASURES

Outcome measures included: Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), FEV1/FVC ratio, Peak Expiratory Flow (PEF), Inspiratory Muscle Strength (MIP), Expiratory Muscle Strength (MEP), Peak Cough Flow (PCF), and Cardiovascular Fitness measures of estimated VO2 max and 6-Minute Walk Test (6MWT).

RESULTS

Compared to published norms, participants had impaired cough, reduced respiratory muscle strength, FEV, FVC, PEF and cardiovascular fitness. Post exercise intervention, statistically significant improvements were noted in MEP, cardiovascular fitness, and PEF. However only gains in PEF were maintained at 4-month follow-up.

CONCLUSIONS

Significant respiratory dysfunction exists, even in the early stages of PD. Metrics of respiratory muscle strength, peak expiratory flow and cardiovascular fitness appear responsive to an integrative exercise programme.

Neurofibromin 1 mediates sleep depth in Drosophila

Neural regulation of sleep and metabolic homeostasis are critical in many aspects of human health. Despite extensive epidemiological evidence linking sleep dysregulation with obesity, diabetes, and metabolic syndrome, little is known about the neural and molecular basis for the integration of sleep and metabolic function. The RAS GTPase-activating gene Neurofibromin (Nf1) has been implicated in the regulation of sleep and metabolic rate, raising the possibility that it serves to integrate these processes, but the effects on sleep consolidation and physiology remain poorly understood. A key hallmark of sleep depth in mammals and flies is a reduction in metabolic rate during sleep. Here, we examine multiple measures of sleep quality to determine the effects of Nf1 on sleep-dependent changes in arousal threshold and metabolic rate. Flies lacking Nf1 fail to suppress metabolic rate during sleep, raising the possibility that loss of Nf1 prevents flies from integrating sleep and metabolic state. Sleep of Nf1 mutant flies is fragmented with a reduced arousal threshold in Nf1 mutants, suggesting Nf1 flies fail to enter deep sleep. The effects of Nf1 on sleep can be localized to a subset of neurons expressing the GABAA receptor Rdl. Sleep loss has been associated with changes in gut homeostasis in flies and mammals. Selective knockdown of Nf1 in Rdl-expressing neurons within the nervous system increases gut permeability and reactive oxygen species (ROS) in the gut, raising the possibility that loss of sleep quality contributes to gut dysregulation. Together, these findings suggest Nf1 acts in GABA-sensitive neurons to modulate sleep depth in Drosophila.

Effectiveness of different exercises in improving postural balance among Parkinson's disease patients: a systematic review and network meta-analysis

Background

Exercise has been reported as an effective intervention for Parkinson's disease. However, there is still debate on the what kinds of exercises prior to choosing. This study aimed to compare and rank the different exercises that effectively enhance postural balance in Parkinson's disease patients by quantifying the information gleaned from randomized controlled trials (RCTs).

Methods

We conducted a comprehensive database search, including PubMed, Cochrane Library, Embase, Web of Science, and PsycINFO. The included studies were evaluated for methodological quality by the Cochrane Risk of Bias tool.

Results

The RCTs were collected between the earliest available date and March 2023. Sixty RCTs were included and the total sample size used in the study was 3,537. Thirty-five studies were defined as low risk of bias, twenty-one studies as medium risk of bias, and four studies as high risk of bias. The network meta-analysis results showed that exergaming exercise can significantly improve patients' Timed-Up-and-Go time (SUCRA = 91.5%). Dance can significantly enhance patients' Berg Balance Scale (surface under the cumulative ranking curve, SUCRA = 81.3%), and rhythmical auditory exercise can significantly improve patients' Mini-Balance Evaluation Systems Test score (SUCRA = 95.6%).

Conclusion

Compared with other exercises, exergaming exercise, Dance, and rhythmical auditory exercise showed superior efficacy in improving postural balance among Parkinson's disease patients.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42023411918.

Guidelines on exercise testing and prescription for patients at different stages of Parkinson's disease

BACKGROUND

Exercise is highly recommended in patients with Parkinson's disease (PD). Exercise-induced amelioration of motor, non-motor, and drug-induced symptoms are widely known. However, specific guidelines on exercise testing and prescription in PD are lacking.

OBJECTIVE

This study reviews the literature on exercise-based approaches to the management of symptoms at each stage of the disease and evaluate: (1) the most suitable clinical exercise testing; (2) training programs based on testing outcomes and PD stage; (3) the effects of exercise on antiparkinsonian drugs and to suggest the most effective exercise-medication combination.

METHODS

A systematic search was conducted using the databases MEDLINE, Google Scholar and, Cochrane Library using "Parkinson's Disease AND Physical therapy", "Training AND Parkinson", "Exercise", "Exercise AND Drug" as key words. In addition, references list from the included articles were searched and cross-checked to identify any further potentially eligible studies.

RESULTS

Of a total of 115 records retrieved, 50 (43%) were included. From these, 23 were included under the rubric "exercise testing"; 20 focused on the effectiveness of different types of exercise in PD motor-functional symptoms and neuroprotective effects, throughout disease progression, were included under the rubric "training protocol prescription"; and 7 concern the rubric "interaction between exercise and medication", although none reported consistent results.

CONCLUSIONS

Despite the lack of standardized parameters for exercise testing and prescription, all studies agree that PD patients should be encouraged to regularly train according to their severity-related limitations and their personalized treatment plan. In this manuscript, specific guidelines for tailored clinical testing and prescription are provided for each stage of PD.

Zone-specific damage of the olfactory epithelium under protein restriction

Oxidative stress causes tissue damage, affecting age-related pathologies. Protein restriction (PR) provides a powerful intervention strategy for reducing oxidative stress, which may have a positive effect on individual organs. However, it is unknown whether PR intervention influences the olfactory system. Here, we investigated how 10 months of PR could affect the cell dynamics of the olfactory epithelium (OE) in mice. We found that PR reduced age-related loss of outer hair cells in the cochlea, providing preventive effects against age-related hearing loss. In contrast, PR resulted in reduced mature olfactory sensory neurons (OSNs), increased proliferative basal cells, and increased apoptotic OSNs in zone 1 (the only area containing neurons expressing NQO1 [quinone dehydrogenase 1]) of the OE in comparison with animals given a control diet. Substantial oxidative stress occurred in NQO1-positive cells and induced apoptotic OSNs in zone 1. These results indicate that in contrast to the positive effect on the auditory system, PR induces oxidative stress and structurally and functionally negative effects on OSNs in zone 1, which is probably involved in the bioactivation of NQO1.

Aging membranes: Unexplored functions for lipids in the lifespan of the central nervous system

Lipids constitute a significant group of biological metabolites and the building blocks of all cell membranes. The abundance and stoichiometries of different lipid species are known to vary across the lifespan and metabolic state, yet the functional effects of these changes have been challenging to understand. Here we review the potentially powerful intersection of lipid metabolism, which determines membrane composition, and aging. We first introduce several key lipid classes that are associated with aging and aging-related disease, where they are found in organisms, and how they act on membrane structure and function. Instead of neutral lipids, which have primary roles in energy storage and homeostasis, we review known functions for polar lipids that control the physicochemical properties of cell membranes. We then focus on aging processes in the central nervous system (CNS), which is enriched in lipids and is highly dependent on membrane structure for function. Recent studies show how lipids act not just as biomarkers of aging and associated changes in the CNS, but as direct mediators of these processes. As a model system, we explore how fatty acid composition in the retina impact aging and aging-related disease. We propose that the biophysical effects of membrane structure on fundamental eukaryotic processes - mitochondrial respiration and autophagy - provide avenues by which lipid dysregulation can accelerate aging processes. Finally, we lay out ways in which an increased understanding of lipid membrane biology can be applied to studies of aging and lifespan.

Enterobactin, an iron chelating bacterial siderophore, arrests cancer cell proliferation

Iron is essential for many biological functions, including being a cofactor for enzymes involved in cell proliferation. In line, it has been shown that cancer cells can perturb their iron metabolism towards retaining an abundant iron supply for growth and survival. Accordingly, it has been suggested that iron deprivation through the use of iron chelators could attenuate cancer progression. While they have exhibited anti-tumor properties in vitro, the current therapeutic iron chelators are inadequate due to their low efficacy. Therefore, we investigated whether the bacterial catecholate-type siderophore, enterobactin (Ent), could be used as a potent anti-cancer agent given its strong iron chelation property. We demonstrated that iron-free Ent can exert cytotoxic effects specifically towards monocyte-related tumor cell lines (RAW264.7 and J774A.1), but not primary cells, i.e. bone marrow-derived macrophages (BMDMs), through two mechanisms. First, we observed that RAW264.7 and J774A.1 cells preserve a bountiful intracellular labile iron pool (LIP), whose homeostasis can be disrupted by Ent. This may be due, in part, to the lower levels of lipocalin 2 (Lcn2; an Ent-binding protein) in these cell lines, whereas the higher levels of Lcn2 in BMDMs could prevent Ent from hindering their LIP. Secondly, we observed that Ent could dose-dependently impede reactive oxygen species (ROS) generation in the mitochondria. Such disruption in LIP balance and mitochondrial function may in turn promote cancer cell apoptosis. Collectively, our study highlights Ent as an anti-cancer siderophore, which can be exploited as an unique agent for cancer therapy.

Precompetitional Weight Reduction Modifies Prooxidative-Antioxidative Status in Judokas

Objective

The main aim of the study was an assessment of the influence of rapid weight loss on oxidative stress parameters in judokas differing in weight reduction value.

Materials and Methods

The study included 30 judokas with an age range of 18-30 years (mean age: 22.4 ± 3.40 years). Enzymatic and nonenzymatic antioxidative markers, lipid peroxidation markers, and total oxidative stress were assessed three times: one week before a competition (the first stage), after gaining the desired weight (the second stage), and one week after the competition (the third stage).

Results

Between the first and the second stage, the concentration of lipid hydroperoxides (LPH) decreased significantly. The superoxide dismutase (SOD), copper- and zinc-containing superoxide dismutase (Cu,Zn-SOD), ceruloplasmin (CER), malondialdehyde (MDA), LPH, and total oxidative stress (TOS) concentrations were the lowest one week after the competition. Linear regression indicated that the emphases on increased weight reduction increased the activity of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and protein sulfhydryl (PSH) between the first and the second stage of the study. Moderate weight reduction (2-5%) resulted in elevated levels of SOD, Mn-SOD, LPH, MDA, and TOS in comparison to low and high reductions. An opposite relation was observed in PSH. In judokas, the precompetitional weight reduction range was 0.44-6.10% (mean: 2.93% ± 1.76%) of the initial body weight. Concentrations of superoxide dismutase (SOD; p < .01), manganese-dependent superoxide dismutase (Mn-SOD; p < .001), and ceruloplasmin (CER; p < .05) decreased between the first and the third stage of the study as well between the second and third one. Before competitions, a decrease in lipid hydroperoxide (LPH; p < .01) concentration was observed. A reduction of malondialdehyde (MDA; p < .05), LPH (p < .01), and total oxidative stress (TOS; p < .05) levels between the first and the final stage occurred. The increase in weight reduction was linearly correlated with the rise of glutathione peroxidase (GPx; p < .05), glutathione reductase (GR; p < .05), glutathione S-transferase (GST; p < .05), and protein sulfhydryl (PSH; p < .05) concentrations between the first and the second stage of the study. Moderate weight reduction (2-5%) resulted in elevated levels of SOD (p < .05), Mn-SOD (p < .05), LPH (p < .05), MDA (p < .05), and TOS (p < .05) in comparison to low and high reductions. An opposite relation was observed in PSH (p < .005).

Conclusions

The effect of weight reduction in judo athletes on prooxidative-antioxidative system diversity depends on the weight reduction value.

OXIDATIVE STRESS IS MARKEDLY REDUCED BY COMBINED VOLUNTARY EXERCISE AND TESTOSTERONE IN THE HEART OF DIABETIC RATS

Objective

Cardiovascular disorders in diabetes condition arise from increased oxidative stress. Both regular mild exercise and testosterone influence on body's antioxidant system in diabetes. In this study, we evaluated treatment of testosterone and voluntary exercise, alone or together on oxidative stress in the heart and blood of diabetic rats.

Methods

Type 1 diabetes was induced by intraperitoneal injection of 50 mg/kg of streptozotocin in rats. Sixty three rats have been divided into eight groups as follows: Diabetes, diabetes+ testosterone, diabetes+ exercise, diabetes+ testosterone+ exercise, diabetes+ castration, diabetes+ castration+ testosterone, Diabetes+ castration+ exercise, Diabetes+ castration+ exercise+ testosterone. Type 1 diabetes was induced by intraperitoneal injection of 50 mg/kg of streptozotocin in the male Wistar rats and after a week, castration was performed. After 42 days of treatment with testosterone (2 mg/kg/day) or voluntary exercise alone or in combination, SOD, GPX and CAT activities and MDA levels were measured in the blood and heart tissue samples in the groups of study. In the end of study, SOD, GPX and CAT activities and MDA levels were measured in blood and heart tissue samples in the groups of study.

Results

SOD, GPX and CAT activities significantly (p<0.05) increased in groups that treated either testosterone or exercise and MDA level significantly (p<0.01) decreased in the blood and heart tissue of diabetic and castrated diabetic rats. Simultaneously, treatment with testosterone and exercise had a synergistic effect on antioxidant enzymes level in diabetic and diabetic castrated rats. In the castrated animals with diabetes, SOD, GPX and CAT activities significantly decreased (p<0.05) and MDA levels significantly increased (p<0.05) in blood and heart tissue.

Conclusion

Voluntary exercise and testosterone alone or together heightened body's antioxidant system and were able to reduce the MDA levels in blood and heart of diabetic and castrated diabetic rats.

Dorsal-zone-specific reduction of sensory neuron density in the olfactory epithelium following long-term exercise or caloric restriction

Exercise (Ex) and caloric restriction (CR) reduce oxidative stress and improve organ function. For instance, voluntary Ex or CR is known to reduce age-related cochlear damage in male C57BL/6J mice. However, the effect of Ex and CR on the olfactory system is unknown. In this study, we confirmed the positive effect of Ex and CR on age-related cochlear damage, but found that Ex and CR affected negatively cell dynamics in the olfactory epithelium (OE) by reducing the number of mature olfactory sensory neurons (OSNs) and increasing the number of proliferative basal cells and apoptotic OSNs in the dorsal zone of the olfactory epithelium (OE), which contains neurons expressing NADPH quinone oxido-reductase 1 (NQO1). In addition, these interventions resulted in lower odor-induced c-fos expression in areas of the olfactory bulb receiving projections from dorsal-zone OSNs than in areas receiving ventral-zone projections. Further, we observed substantial oxidative stress in NQO1-positive cells and apoptotic OSNs in the dorsal zone in Ex and CR animals. These results suggest that, in contrast to their positive effects in other organs, Ex and CR facilitate oxidative stress and negatively impact structure and function in dorsal-zone OSNs, probably in association with NQO1 bioactivation.

The MAPK-activator protein-1 signaling regulates changes in lung tissue of rat exposed to hypobaric hypoxia

This study reports the role of MAPKs (JNK, ERK, and p38), and activator protein-1 (AP-1) transcription factor in the hypobaric hypoxia induced change in lung tissue. Healthy male Sprague-Dawley rats were exposed to hypobaric hypoxia for 6, 12, 24, 48, 72, and 120 hr. Hypoxia resulted in significant increase in reactive oxygen species (ROS), vascular endothelial growth factor (VEGF) and decreased nitric oxide (NO), these act as signaling molecules for activation of MAPK and also contribute in development of vascular leakage (an indicator of pulmonary edema) as confirmed by histological studies. Our results confirmed JNK activation as an immediate early response (peaked at 6-48 hr), activation of ERKs (peaked at 24-72 hr) and p38 (peaked at 72-120 hr) as a secondary response to hypoxia. The MAPK pathway up regulated its downstream targets phospho c-Jun (peaked at 6-120 hr), JunB (peaked at 24-120 hr) however, decreased c-Fos, and JunD levels. DNA binding activity also confirmed activation of AP-1 transcription factor in lung tissue under hypobaric hypoxia. Further, we analyzed the proliferative and inflammatory genes regulated by different subunits of AP-1 to explore its role in vascular leakage. Increased expression of cyclin D1 (peaked at 12-72 hr) and p16 level (peaked at 48-120 hr) were correlated to the activation of c-jun, c-Fos and JunB. Administration of NFκB inhibitor caffeic acid phenethyl ester (CAPE) and SP600125 (JNK inhibitor) had no effect on increased levels of Interferon-γ (IFN-γ), Interleukin-1 (IL-1), and Tumor Necrosis Factor-α (TNF-α) thereby confirming the involvement of AP-1 as well as NFκB in inflammation. Expression of c-jun, c-Fos were correlated with activation of proliferative genes and JunB, Fra-1 with pro-inflammatory cytokines. In conclusion immediate response to hypobaric hypoxia induced c-Jun:c-Fos subunits of AP-1; responsible for proliferation that might cause inhomogeneous vasoconstriction leading to vascular leakage and inflammation at increased duration of hypobaric hypoxia exposure.

Mitochondrial Toxicity

Recent decades have seen a rapid increase in reported toxic effects of drugs and pollutants on mitochondria. Researchers have also documented many genetic differences leading to mitochondrial diseases, currently reported to affect ∼1 person in 4,300, creating a large number of potential gene-environment interactions in mitochondrial toxicity. We briefly review this history, and then highlight cutting-edge areas of mitochondrial research including the role of mitochondrial reactive oxygen species in signaling; increased understanding of fundamental biological processes involved in mitochondrial homeostasis (DNA maintenance and mutagenesis, mitochondrial stress response pathways, fusion and fission, autophagy and biogenesis, and exocytosis); systemic effects resulting from mitochondrial stresses in specific cell types; mitochondrial involvement in immune function; the growing evidence of long-term effects of mitochondrial toxicity; mitochondrial-epigenetic cross-talk; and newer approaches to test chemicals for mitochondrial toxicity. We also discuss the potential importance of hormetic effects of mitochondrial stressors. Finally, we comment on future areas of research we consider critical for mitochondrial toxicology, including increased integration of clinical, experimental laboratory, and epidemiological (human and wildlife) studies; improved understanding of biomarkers in the human population; and incorporation of other factors that affect mitochondria, such as diet, exercise, age, and nonchemical stressors.

Sansevieria roxburghiana Schult. & Schult. F. (Family: Asparagaceae) Attenuates Type 2 Diabetes and Its Associated Cardiomyopathy

BACKGROUND

Sansevieria roxburghiana Schult. & Schult. F. (Family: Asparagaceae) rhizome has been claimed to possess antidiabetic activity in the ethno-medicinal literature in India. Therefore, present experiments were carried out to explore the protective role of edible (aqueous) extract of S. roxburghiana rhizome (SR) against experimentally induced type 2 diabetes mellitus (T2DM) and its associated cardiomyopathy in Wistar rats.

METHODS

SR was chemically characterized by GC-MS analysis. Antidiabetic activity of SR (50 and 100 mg/kg, orally) was measured in high fat diets (ad libitum) + low-single dose of streptozotocin (35 mg/kg, intraperitoneal) induced type 2 diabetic (T2D) rat. Fasting blood glucose level was measured at specific intermissions. Serum biochemical and inflammatory markers were estimated after sacrificing the animals. Besides, myocardial redox status, expressions of signal proteins (NF-κB and PKCs), histological and ultrastructural studies of heart were performed in the controls and SR treated T2D rats.

RESULTS

Phytochemical screening of the crude extract revealed the presence of phenolic compounds, sugar alcohols, sterols, amino acids, saturated fatty acids within SR. T2D rats exhibited significantly (p < 0.01) higher fasting blood glucose level with respect to control. Alteration in serum lipid profile (p < 0.01) and increased levels of lactate dehydrogenase (p < 0.01) and creatine kinase (p < 0.01) in the sera revealed the occurrence of hyperlipidemia and cell destruction in T2D rats. T2DM caused significant (p < 0.05-0.01) alteration in the biochemical markers in the sera. T2DM altered the redox status (p < 0.05-0.01), decreased (p < 0.01) the intracellular NAD and ATP concentrations in the myocardial tissues of experimental rats. While investigating the molecular mechanism, activation PKC isoforms was observed in the selected tissues. T2D rats also exhibited an up-regulation in nuclear NF-κB (p65) in the cardiac tissues. So, oral administration of SR (50 and 500 mg/kg) could reduce hyperglycemia, hyperlipidemia, membrane disintegration, oxidative stress, vascular inflammation and prevented the activation of oxidative stress induced signaling cascades leading to cell death. Histological and ultra-structural studies of cardiac tissues supported the protective characteristics of SR.

CONCLUSIONS

From the present findings it can be concluded that, SR could offer protection against T2DM and its associated cardio-toxicity via multiple mechanisms viz. hypoglycemic, antioxidant and anti-inflammatory actions.

Novel RNA-binding activity of NQO1 promotes SERPINA1 mRNA translation

NAD(P)H: quinone oxidoreductase (NQO1) is essential for cell defense against reactive oxidative species, cancer, and metabolic stress. Recently, NQO1 was found in ribonucleoprotein (RNP) complexes, but NQO1-interacting mRNAs and the functional impact of such interactions are not known. Here, we used ribonucleoprotein immunoprecipitation (RIP) and microarray analysis to identify comprehensively the subset of NQO1 target mRNAs in human hepatoma HepG2 cells. One of its main targets, SERPINA1 mRNA, encodes the serine protease inhibitor α-1-antitrypsin, A1AT, which is associated with disorders including obesity-related metabolic inflammation, chronic obstructive pulmonary disease (COPD), liver cirrhosis and hepatocellular carcinoma. Biotin pulldown analysis indicated that NQO1 can bind the 3' untranslated region (UTR) and the coding region (CR) of SERPINA1 mRNA. NQO1 did not affect SERPINA1 mRNA levels; instead, it enhanced the translation of SERPINA1 mRNA, as NQO1 silencing decreased the size of polysomes forming on SERPINA1 mRNA and lowered the abundance of A1AT. Luciferase reporter analysis further indicated that NQO1 regulates SERPINA1 mRNA translation through the SERPINA1 3'UTR. Accordingly, NQO1-KO mice had reduced hepatic and serum levels of A1AT and increased activity of neutrophil elastase (NE), one of the main targets of A1AT. We propose that this novel mechanism of action of NQO1 as an RNA-binding protein may help to explain its pleiotropic biological effects.

Impact of aerobic and anaerobic exercise training on oxidative stress and antioxidant defense in athletes

Exercise mediates an excessive free radical production leading to oxidative stress (OS). The body has natural antioxidant systems that help decrease OS, and these systems may be enhanced with exercise training. However, only a few studies have investigated the differences in resting OS and antioxidant capacity (AOC) between aerobically trained athletes (ET), anaerobically trained athletes (RT), and untrained individuals (UT). Therefore, this study sought to investigate the resting and postexercise OS and AOC in ET, RT, and UT. Sixty healthy young males (26.6±0.8 yr) participated in this study. Subjects were divided into three groups, ET, RT, and UT by distinct training background. Resting plasma malondialdehyde (MDA) and protein carbonyls (PC) were not significantly different in ET, RT, and UT. However, MDA and PC were significantly increased following a graded exercise test (GXT) in UT but not in ET and RT. Resting total antioxidant capacity (TAC) levels and TAC were not different in ET, RT, and UT. Interestingly, TAC levels significantly decreased after the GXT in all groups. Additionally, UT showed lower post-exercise TAC levels compared to ET and RT. These results showed that ET, RT, and UT have similar OS and AOC at rest. However, both ET and RT have greater AOC against exercise mediated OS compared to UT. These findings may explain, at least in part, why both aerobic and anaerobic types of exercise training improve redox balance. However, it appears there is no specific exercise type effect in terms of redox balance.

Cytoprotective and Antioxidant Effects of an Edible Herb, Enhydra fluctuans Lour. (Asteraceae), against Experimentally Induced Lead Acetate Intoxication

Background

Enhydra fluctuans Lour. (Asteraceae), an edible aquatic herb, is traditionally employed against toxic effects of heavy metals in India. The present study was planned to discover the protective effect of edible extract of E. fluctuans (AEEF) against Pb toxicity.

Methods

The cytoprotective role of AEEF was determined on murine hepatocytes employing MTT assay and Hoechst staining. The effects on lipid peroxidation, protein carbonylation, endogenous redox systems and the transcription levels of apoptotic proteins were studied after incubating the hepatocytes with AEEF (400 μg/ml) + Pb-acetate (6.8 μM). The defensive role of AEEF (100 mg/kg) against Pb-acetate (5 mg/kg) intoxication was measured in mice by in vivo assays. Biochemical, haematological and histological parameters, intracellular Pb burden and redox status were measured.

Results

AEEF exhibited a concentration dependent cytoprotective effect against Pb-induced cytotoxicity in vitro. Pb-acetate incubation significantly (p < 0.01) altered the extents of ROS production ↑, protein carbonylation ↑, lipid peroxidation ↑, endogenous antioxidant enzymes ↓ and GSH ↓ in vitro. Besides, Pb-acetate significantly (p < 0.01) induced apoptosis in the hepatocytes apparent from the altered expressions of apoptotic proteins viz. Apaf-1 ↑, Bad ↑, Bcl-2 ↓, Cyt C ↑, cleaved caspases↑, Bid ↑ and Fas ↑. However, AEEF (400 μg/ml) could significantly (p < 0.05–0.01) attenuate the Pb-acetate mediated toxic manifestation in vitro. In in vivo assay, Pb-acetate (5 mg/kg) treated mice exhibited significantly (p < 0.01) high intracellular Pb content. A high Pb-burden within the tissues caused significant (p < 0.05–0.01) patho-physiological alterations viz. ROS production ↑, protein carbonylation↑, lipid peroxidation ↑, DNA fragmentation ↑, ATP formation ↑, mitochondrial co-enzymes Q ↓, endogenous antioxidant enzymes ↓ and GSH ↓ within the selected tissues. The haematological and serum biochemical parameters were significantly (p < 0.05–0.01) different in the Pb-acetate treated mice. Finally, histological assessment imposed significant toxic occurrence within the organs of Pb-intoxicated animals. However, concurrent administration of AEEF (100 mg/kg) could significantly (p < 0.05–0.01) reinstate the Pb-acetate mediated toxicity.

Conclusion

Presence of metal chelators and phyto-antioxidants within AEEF would offer overall protection through promoting Pb clearance coupled with restoring redox balance.

Exercise Modulates Oxidative Stress and Inflammation in Aging and Cardiovascular Diseases

Despite the wealth of epidemiological and experimental studies indicating the protective role of regular physical activity/exercise training against the sequels of aging and cardiovascular diseases, the molecular transducers of exercise/physical activity benefits are not fully identified but should be further investigated in more integrative and innovative approaches, as they bear the potential for transformative discoveries of novel therapeutic targets. As aging and cardiovascular diseases are associated with a chronic state of oxidative stress and inflammation mediated via complex and interconnected pathways, we will focus in this review on the antioxidant and anti-inflammatory actions of exercise, mainly exerted on adipose tissue, skeletal muscles, immune system, and cardiovascular system by modulating anti-inflammatory/proinflammatory cytokines profile, redox-sensitive transcription factors such as nuclear factor kappa B, activator protein-1, and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, antioxidant and prooxidant enzymes, and repair proteins such as heat shock proteins, proteasome complex, oxoguanine DNA glycosylase, uracil DNA glycosylase, and telomerase. It is important to note that the effects of exercise vary depending on the type, intensity, frequency, and duration of exercise as well as on the individual's characteristics; therefore, the development of personalized exercise programs is essential.

Water Spinach, Ipomoea aquatic (Convolvulaceae), Ameliorates Lead Toxicity by Inhibiting Oxidative Stress and Apoptosis

BACKGROUND

Ipomoea aquatica (Convolvulaceae), an aquatic edible plant, is traditionally used against heavy metal toxicity in India. The current study intended to explore the protective role of edible (aqueous) extract of I. aquatica (AEIA) against experimentally induced Pb-intoxication.

METHODS

The cytoprotective role of AEIA was measured on mouse hepatocytes by cell viability assay followed by Hoechst staining and flow cytometric assay. The effect on ROS production, lipid peroxidation, protein carbonylation, intracellular redox status were measured after incubating the hepatocytes with Pb-acetate (6.8 μM) along with AEIA (400 μg/ml). The effects on the expressions of apoptotic signal proteins were estimated by western blotting. The protective role of AEIA was measured by in vivo assay in mice. Haematological, serum biochemical, tissue redox status, Pb bioaccumulation and histological parameters were evaluated to estimate the protective role of AEIA (100 mg/kg) against Pb-acetate (5 mg/kg) intoxication.

RESULTS

Pb-acetate treated hepatocytes showed a gradual reduction of cell viability dose-dependently with an IC50 value of 6.8 μM. Pb-acetate treated hepatocytes exhibited significantly enhanced levels (p < 0.01) of ROS production, lipid peroxidation, protein carbonylation with concomitant depletion (p < 0.01) of antioxidant enzymes and GSH. However, AEIA treatment could significantly restore the aforementioned parameters in murine hepatocytes near to normalcy. Besides, AEIA significantly reversed (p < 0.05-0.01) the alterations of transcription levels of apoptotic proteins viz. Bcl 2, Bad, Cyt C, Apaf-1, cleaved caspases [caspase 3, caspase 8 and caspase 9], Fas and Bid. In in vivo bioassay, Pb-acetate treatment caused significantly high intracellular Pb burden and oxidative pressure in the kidney, liver, heart, brain and testes in mice. In addition, the haematological and serum biochemical factors were changed significantly in Pb-acetate-treated animals. AEIA treatment restored significantly the evaluated-parameters to the near-normal position.

CONCLUSION

The extract may offer the protective effect via counteracting with Pb mediated oxidative stress and/or promoting the elimination of Pb by chelating. The presence of substantial quantities of flavonoids, phenolics and saponins would be responsible for the overall protective effect.

The effects of two common edible herbs, Ipomoea aquatica and Enhydra fluctuans, on cadmium-induced pathophysiology: a focus on oxidative defence and anti-apoptotic mechanism

Background

Ipomoea aquatica (Convolvulaceae) and Enhydra fluctuans (Asteraceae), two aquatic vegetables, are traditionally used against heavy metal toxicity in traditional medicines in India. The present study aimed to explore the protective role of edible (aqueous) extracts of I. aquatica (AEIA) and E. fluctuans (AEEF) against Cd-intoxication.

Methods

The extracts were chemically standardized by spectroscopic and HPLC analysis. The cytoprotective roles of AEIA and AEEF were measured on mouse hepatocytes. The effect on redox status were measured after incubating the hepatocytes with CdCl₂ (30 μM) along with AEIA or AEEF (400 μg/ml). The effects on the expressions of apoptotic signal proteins were estimated. The protective roles of AEIA or AEEF were measured by in vivo assay in mice. Haematological, serum biochemical, tissue redox status, Cd bioaccumulation and histological parameters were evaluated to estimate the protective role of AEIA or AEEF (100 mg/kg) against CdCl₂ (4 mg/kg) intoxication.

Results

Phytochemical analysis revealed presence of substantial quantities of phenolics, flavonoids, saponins, carbohydrates and ascorbic acid in AEIA or AEEF. CdCl₂ treated murine hepatocytes showed a gradual reduction of cell viability in a concentration dependent manner with an IC₅₀ of ~30 μM. CdCl₂ treated hepatocytes exhibited significantly enhanced levels (p < 0.01) of ROS production, lipid peroxidation, protein carbonylation and NADPH oxidase with concomitant depletion (p < 0.01) of antioxidant enzymes and GSH. However, AEIA or AEEF treatment along with CdCl₂ significantly restored the aforementioned parameters in murine hepatocytes near to normalcy. Besides, AEIA or AEEF significantly counteracted (p < 0.05–0.01) with ROS mediated alteration of transcription levels of signal proteins viz. Bcl-2, BAD, Cyt-C, Caspases, Fas and Bid. In in vivo bioassay, CdCl₂ treatment caused significantly high Cd bioaccumulation and oxidative stress in the liver, kidney, heart, brain and testes in mice. In addition, the haematological and serum biochemical parameters were significantly altered in the CdCl₂ treated animals. Simultaneous administration of AEIA or AEEF could significantly restore the tested parameters to the near-normal status.

Conclusion

The extracts would offer the overall protective effect via counteracting with Cd mediated oxidative stress and/or promoting the elimination of Cd by chelating.

Serum from calorie-restricted animals delays senescence and extends the lifespan of normal human fibroblasts in vitro

The cumulative effects of cellular senescence and cell loss over time in various tissues and organs are considered major contributing factors to the ageing process. In various organisms, caloric restriction (CR) slows ageing and increases lifespan, at least in part, by activating nicotinamide adenine dinucleotide (NAD⁺)-dependent protein deacetylases of the sirtuin family. Here, we use an in vitro model of CR to study the effects of this dietary regime on replicative senescence, cellular lifespan and modulation of the SIRT1 signaling pathway in normal human diploid fibroblasts. We found that serum from calorie-restricted animals was able to delay senescence and significantly increase replicative lifespan in these cells, when compared to serum from ad libitum fed animals. These effects correlated with CR-mediated increases in SIRT1 and decreases in p53 expression levels. In addition, we show that manipulation of SIRT1 levels by either over-expression or siRNA-mediated knockdown resulted in delayed and accelerated cellular senescence, respectively. Our results demonstrate that CR can delay senescence and increase replicative lifespan of normal human diploid fibroblasts in vitro and suggest that SIRT1 plays an important role in these processes. (185 words).

Voluntary Exercise Protects Heart from Oxidative Stress in Diabetic Rats

PURPOSE

Oxidative stress plays a key role in the onset and development of diabetes complications. In this study, we evaluated whether voluntary exercise could alleviate oxidative stress in the heart and blood of streptozotocin - induced diabetic rats.

METHODS

28 male Wistar rats were randomly divided into four groups (n=7): control, exercise, diabetes and exercise + diabetes. Diabetes was induced by injection of streptozotocin in male rats. Rats in the trained groups were subjected to voluntary running wheel exercise for 6 weeks. At the end of six weeks blood and heart tissue samples were collected and used for determination of antioxidant enzymes (including SOD, GPX and CAT activities) and MDA level.

RESULTS

Exercise significantly reduced MDA levels both in the heart tissue (p<0.01) and blood samples (p<0.05). In addition, exercise significantly increased SOD (p<0.05), GPX (p<0.001) and CAT (p<0.05) in the heart tissue. Voluntary exercise also significantly increased SOD (p<0.01), GPX (p<0.05) and CAT (p<0.001) in the blood.

CONCLUSION

Voluntary exercise diminishes the MDA level in blood and heart tissue of diabetic rats. It also accentuates activities of SOD, GPX and CAT. Therefore, it may be considered a useful tool for the reduction of oxidative stress in diabetes.

Abroma augusta L. (Malvaceae) leaf extract attenuates diabetes induced nephropathy and cardiomyopathy via inhibition of oxidative stress and inflammatory response

BACKGROUND

Abroma augusta L. (Malvaceae) leaf is traditionally used to treat diabetes in India and Southern Asia. Therefore, current study was performed to evaluate the protective effect of defatted methanol extract of A. augusta leaves (AA) against type 2 diabetes mellitus (T2DM) and its associated nephropathy and cardiomyopathy in experimental rats.

METHODS

Antidiabetic activity of AA extracts (100 and 200 mg/kg, p.o.) was measured in streptozotocin-nicotinamide induced type 2 diabetic (T2D) rat. Fasting blood glucose level (at specific interval) and serum biochemical markers (after sacrifice) were measured. Redox status, transcription levels of signal proteins (NF-κB and PKCs), mitochondria dependent apoptotic pathway (Bad, Bcl-2, caspase cascade) and histological studies were performed in kidneys and hearts of controls and AA treated diabetic rats.

RESULTS

Phytochemical screening of extracts revealed the presence of taraxerol, flavonoids and phenolic compounds in the AA. T2D rats showed significantly (p < 0.01) elevated fasting blood glucose level. Alteration in serum lipid profile and release of membrane bound enzymes like lactate dehydrogenase and creatine kinase, which ensured the participation of hyperlipidemia and cell membrane disintegration in diabetic pathophysiology. T2DM caused alteration in the serum biochemical markers related to diabetic complications. T2DM altered the redox status, decreased the intracellular NAD and ATP concentrations in renal and myocardial tissues of experimental rats. Investigating the molecular mechanism, activation PKC isoforms was observed in the selected tissues. T2D rats also exhibited an up-regulation of NF-κB and increase in the concentrations of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) in the renal and cardiac tissues. The activation of mitochondria dependent apoptotic pathway was observed in renal and myocardial tissues of the T2D rats. However, Oral administration of AA at the doses of 100 and 200 mg/kg body weight per day could reduce hyperglycemia, hyperlipidemia, membrane disintegration, oxidative stress, vascular inflammation and prevented the activation of oxidative stress induced signaling cascades leading to cell death. Histological studies also supported the protective characteristics of AA.

CONCLUSIONS

Results suggest that AA could offer prophylactic role against T2DM and its associated reno- and cardio- toxicity.

Mangiferin attenuates diabetic nephropathy by inhibiting oxidative stress mediated signaling cascade, TNFα related and mitochondrial dependent apoptotic pathways in streptozotocin-induced diabetic rats

Oxidative stress plays a crucial role in the progression of diabetic nephropathy in hyperglycemic conditions. It has already been reported that mangiferin, a natural C-glucosyl xanthone and polyhydroxy polyphenol compound protects kidneys from diabetic nephropathy. However, little is known about the mechanism of its beneficial action in this pathophysiology. The present study, therefore, examines the detailed mechanism of the beneficial action of mangiferin on STZ-induced diabetic nephropathy in Wister rats as the working model. A significant increase in plasma glucose level, kidney to body weight ratio, glomerular hypertrophy and hydropic changes as well as enhanced nephrotoxicity related markers (BUN, plasma creatinine, uric acid and urinary albumin) were observed in the experimental animals. Furthermore, increased oxidative stress related parameters, increased ROS production and decreased the intracellular antioxidant defenses were detected in the kidney. Studies on the oxidative stress mediated signaling cascades in diabetic nephropathy demonstrated that PKC isoforms (PKCα, PKCβ and PKCε), MAPKs (p38, JNK and ERK1/2), transcription factor (NF-κB) and TGF-β1 pathways were involved in this pathophysiology. Besides, TNFα was released in this hyperglycemic condition, which in turn activated caspase 8, cleaved Bid to tBid and finally the mitochorndia-dependent apoptotic pathway. In addition, oxidative stress also disturbed the proapoptotic-antiapoptotic (Bax and Bcl-2) balance and activated mitochorndia-dependent apoptosis via caspase 9, caspase 3 and PARP cleavage. Mangiferin treatment, post to hyperglycemia, successfully inhibited all of these changes and protected the cells from apoptotic death.

Exogenous sphingosine-1-phosphate boosts acclimatization in rats exposed to acute hypobaric hypoxia: assessment of haematological and metabolic effects

Background

The physiological challenges posed by hypobaric hypoxia warrant exploration of pharmacological entities to improve acclimatization to hypoxia. The present study investigates the preclinical efficacy of sphingosine-1-phosphate (S1P) to improve acclimatization to simulated hypobaric hypoxia.

Experimental Approach

Efficacy of intravenously administered S1P in improving haematological and metabolic acclimatization was evaluated in rats exposed to simulated acute hypobaric hypoxia (7620m for 6 hours) following S1P pre-treatment for three days.

Major Findings

Altitude exposure of the control rats caused systemic hypoxia, hypocapnia (plausible sign of hyperventilation) and respiratory alkalosis due to suboptimal renal compensation indicated by an overt alkaline pH of the mixed venous blood. This was associated with pronounced energy deficit in the hepatic tissue along with systemic oxidative stress and inflammation. S1P pre-treatment improved blood oxygen-carrying-capacity by increasing haemoglobin, haematocrit, and RBC count, probably as an outcome of hypoxia inducible factor-1α mediated erythropoiesis and renal S1P receptor 1 mediated haemoconcentation. The improved partial pressure of oxygen in the blood could further restore aerobic respiration and increase ATP content in the hepatic tissue of S1P treated animals. S1P could also protect the animals from hypoxia mediated oxidative stress and inflammation.

Conclusion

The study findings highlight S1P’s merits as a preconditioning agent for improving acclimatization to acute hypobaric hypoxia exposure. The results may have long term clinical application for improving physiological acclimatization of subjects venturing into high altitude for occupational or recreational purposes.

The effects of dietary restriction on oxidative stress in rodents

Oxidative stress is observed during aging and in numerous age-related diseases. Dietary restriction (DR) is a regimen that protects against disease and extends life span in multiple species. However, it is unknown how DR mediates its protective effects. One prominent and consistent effect of DR in a number of systems is the ability to reduce oxidative stress and damage. The purpose of this review is to comprehensively examine the hypothesis that dietary restriction reduces oxidative stress in rodents by decreasing reactive oxygen species (ROS) production and increasing antioxidant enzyme activity, leading to an overall reduction of oxidative damage to macromolecules. The literature reveals that the effects of DR on oxidative stress are complex and likely influenced by a variety of factors, including sex, species, tissue examined, types of ROS and antioxidant enzymes examined, and duration of DR. Here we present a comprehensive review of the existing literature on the effect of DR on mitochondrial ROS generation, antioxidant enzymes, and oxidative damage. In a majority of studies, dietary restriction had little effect on mitochondrial ROS production or antioxidant activity. On the other hand, DR decreased oxidative damage in the majority of cases. Although the effects of DR on endogenous antioxidants are mixed, we find that glutathione levels are the most likely antioxidant to be increased by dietary restriction, which supports the emerging redox-stress hypothesis of aging.

Metabolic adaptations to short-term every-other-day feeding in long-living Ames dwarf mice

Restrictive dietary interventions exert significant beneficial physiological effects in terms of aging and age-related disease in many species. Every other day feeding (EOD) has been utilized in aging research and shown to mimic many of the positive outcomes consequent with dietary restriction. This study employed long living Ames dwarf mice subjected to EOD feeding to examine the adaptations of the oxidative phosphorylation and antioxidative defense systems to this feeding regimen. Every other day feeding lowered liver glutathione (GSH) concentrations in dwarf and wild type (WT) mice but altered GSH biosynthesis and degradation in WT mice only. The activities of liver OXPHOS enzymes and corresponding proteins declined in WT mice fed EOD while in dwarf animals, the levels were maintained or increased with this feeding regimen. Antioxidative enzymes were differentially affected depending on the tissue, whether proliferative or post-mitotic. Gene expression of components of liver methionine metabolism remained elevated in dwarf mice when compared to WT mice as previously reported however, enzymes responsible for recycling homocysteine to methionine were elevated in both genotypes in response to EOD feeding. The data suggest that the differences in anabolic hormone levels likely affect the sensitivity of long living and control mice to this dietary regimen, with dwarf mice exhibiting fewer responses in comparison to WT mice. These results provide further evidence that dwarf mice may be better protected against metabolic and environmental perturbations which may in turn, contribute to their extended longevity.

Effect of subchronic hypobaric hypoxia on oxidative stress in rat heart

We examined the effect of subchronic hypobaric hypoxia in rat heart. Adult male Sprague-Dawley rats were exposed at 25,000 ft for different time periods (2 and 5 days). Susceptibility of their hearts to oxidative stress as well as modulation in gene expression was evaluated. The results showed a crosstalk between reactive oxygen species (ROS) and nitric oxide (NO), initial response was accompanied by increase in ROS generation and development of oxidative stress as confirmed by increased lipid peroxidation, protein oxidation and accumulation of 2, 4-dinitrophenyl hydrazine and 4-hydroxy-2-nonenal adducts. At the same time, glutathione activity decreased; however, antioxidant enzymatic activities of superoxide dismutases, glutathione-S-transferase, and glutathione peroxidase rose in response to 5-days hypoxia. Interestingly, NO level increased till 5 days, however ROS decreased after 5 days; this observation suggests that ROS/NO balance plays an important role in cardioprotection. This observation is further supported by upregulation of antioxidant genes hemeoxygenase (HO-1) and metallothionein (MT). In addition, hypoxia also induces gradual upregulation of hypoxia-inducible transcription factor (HIF-1α), which in turn induces the expression of adaptive genes erythropoiesis, vascular endothelial growth factor, glucose transporter-1, nitric oxide synthase. Collectively, our data suggests a reciprocal regulation of ROS and NO and this effect is mediated by the increase in antioxidant proteins HO-1 and MT. Along with this HIF-1-mediated induction of various cardioprotective genes also plays an important role in acclimatization.

Mangiferin, a natural xanthone, protects murine liver in Pb(II) induced hepatic damage and cell death via MAP kinase, NF-κB and mitochondria dependent pathways

One of the most well-known naturally occurring environmental heavy metals, lead (Pb) has been reported to cause liver injury and cellular apoptosis by disturbing the prooxidant-antioxidant balance via oxidative stress. Several studies, on the other hand, reported that mangiferin, a naturally occurring xanthone, has been used for a broad range of therapeutic purposes. In the present study, we, therefore, investigated the molecular mechanisms of the protective action of mangiferin against lead-induced hepatic pathophysiology. Lead [Pb(II)] in the form of Pb(NO₃)₂ (at a dose of 5 mg/kg body weight, 6 days, orally) induced oxidative stress, hepatic dysfunction and cell death in murine liver. Post treatment of mangiferin at a dose of 100 mg/kg body weight (6 days, orally), on the other hand, diminished the formation of reactive oxygen species (ROS) and reduced the levels of serum marker enzymes [alanine aminotranferase (ALT) and alkaline phosphatase (ALP)]. Mangiferin also reduced Pb(II) induced alterations in antioxidant machineries, restored the mitochondrial membrane potential as well as mutual regulation of Bcl-2/Bax. Furthermore, mangiferin inhibited Pb(II)-induced activation of mitogen-activated protein kinases (MAPKs) (phospho-ERK 1/2, phosphor-JNK phospho- p38), nuclear translocation of NF-κB and apoptotic cell death as was evidenced by DNA fragmentation, FACS analysis and histological assessment. In vitro studies using hepatocytes as the working model also showed the protective effect of mangiferin in Pb(II) induced cytotoxicity. All these beneficial effects of mangiferin contributes to the considerable reduction of apoptotic hepatic cell death induced by Pb(II). Overall results demonstrate that mangiferin exhibit both antioxidative and antiapoptotic properties and protects the organ in Pb(II) induced hepatic dysfunction.

Dose-dependent effects of ladostigil on microglial activation and cognition in aged rats

The current study determined the effects of chronic treatment of aging rats with ladostigil, a cholinesterase (ChE) and monoamine oxidase (MAO) inhibitor, at doses of 1 and 8.5 mg/kg/day, on novel object recognition (NOR) and reference memory in the Morris water maze (MWM). A dose of (1 mg/kg/day) did not inhibit ChE or MAO but prevented the loss of NOR and reference memory in the MWM that occurs at 20.5 months of age. This anti-aging effect was associated with a reduction in the expression of CD11b, a marker of microglial activation, in the fornix and parietal cortex and restoration of microglial morphology to that in young adult rats. Ladostigil (8.5 mg/kg/day) inhibited brain ChE by ≈30 % and MAO A and B by 55-59 %, and had a similar, or greater effect than the low dose on microglia, but was less effective in preventing the decline in NOR. Ladostigil (8.5 mg/kg/day) may have caused too much cortical ChE inhibition and acetylcholine elevation at 16 months when NOR was intact. In support of this suggestion we showed that acute administration of ladostigil (8.5 mg/kg) worsened NOR at this age. However, at 20 months, when NOR was impaired and brain acetylcholine levels are 40 % below normal, ladostigil (8.5 mg/kg) reversed the memory deficit.

CONCLUSION

Ladostigil (1 mg/kg/day) prevents the development of age-related memory deficits by a combination of immunomodulatory and antioxidant effects. A dose causing 30 % ChE inhibition is necessary in order to reverse existing memory deficits at 20 months of age.

A 6-week training program increased muscle antioxidant system in elderly diabetic fatty rats

Background

It is widely accepted that oxidative stress is associated with the physiopathology of type 2 diabetes mellitus. In fact, it has been pointed out as a therapeutic target in T2DM. Fortunately, several papers have reported that long-term training programs improved the antioxidant system in young and adult diabetic rats. Accordingly, this study was designed to assess the influence of a shorter training program in elderly diabetic fatty rats.

Material/Methods

Study subjects were 24 male homozygous Zucker diabetic fatty rats (Gmi, fa/fa) aged 18 weeks with an average weight of 370–450 g. After a 2-week period of environmental adaptation, animals were randomly distributed into the Exercised Group (n=12) that performed a 6-week swimming training protocol and the Sedentary Group (n=12). Animals were sacrificed under anesthesia 24 h after the last exercise session. Serum metabolic profile was determined. Total antioxidant status (TAS), MnSOD expression, glutathione status and ROS generation were assayed in gastrocnemius muscle.

Results

When compared with controls, exercised rats significantly improved their metabolic profile. Total antioxidant status (0.19±0.002 vs. 0.13±0.002 μg/mg protein; p<0.001) and MnSOD expression (8471±90 vs. 6258±102 U/μg protein; p=0.003) were also increased in exercised rats.

Conclusions

A 6-week swimming training program improved the antioxidant system in elderly fatty diabetic rats. Fortunately, this improvement was enough to reduce oxidative damage, expressed as protein oxidation. A major finding of this study was that our training protocol lasted just 6 weeks, in contrast to longer protocols previously published.

Construction of two novel reciprocal conplastic rat strains and characterization of cardiac mitochondria

Because of the lack of appropriate animal models, the potentially causal contributions of inherited mitochondrial genomic factors to complex traits are less well studied compared with inherited nuclear genomic factors. We previously detected variations between the mitochondrial DNA (mtDNA) of the Dahl salt-sensitive (S) rat and the spontaneously hypertensive rat (SHR). Specifically, multiple variations were detected in mitochondrial genes coding for subunits of proteins essential for electron transport, in mitochondrial reactive oxygen species production, and within the D-loop region. To evaluate the effects of these mtDNA variations in the absence of the corresponding nuclear genomic factors as confounding variables, novel reciprocal strains of S and SHR were constructed and characterized. When compared with that of the S rat, the heart tissue from the S.SHR(mt) conplastic strain wherein the mtDNA of the S rat was substituted with that of the SHR had a significant increase in mtDNA copy number and decrease in mitochondrial reactive oxygen species production. A corresponding increase in aerobic treadmill running capacity and a significant increase in survival that was not related to changes in blood pressure were observed in the S.SHR(mt) rats compared with the S rat. The reciprocal SHR.S(mt) rats did not differ from the SHR in any phenotype tested, suggesting lower penetrance of the S mtDNA on the nuclear genomic background of the SHR. These novel conplastic strains serve as invaluable tools to further dissect the relationship between heart function, aerobic fitness, cardiovascular disease progression, and mortality.

Contribution of nano-copper particles to in vivo liver dysfunction and cellular damage: role of IκBα/NF-κB, MAPKs and mitochondrial signal

The present study investigated the oxidative stress responsive cell signaling in nano-copper-induced hepatic dysfunction and cell death. Exposure to nano-copper (18 nm) dose-dependently (200-600 mg/kg bw) reduced the hepatic index, caused oxidative stress and led to hepatic dysfunction. Nano-copper burden also increased the transcriptional activity of NF-κB, up-regulated the expression of phosphorylated p38, ERK1/2 and caused the reciprocal regulation of Bcl-2 family proteins, disruption of mitochondrial membrane potential, release of cytochrome C, formation of apoptosome and activation of caspase 3. DAPI staining, immunofluorescence study, FACS analysis and histological findings also support this observation. Soluble copper (Cu(+2), 110 mg/kg bw)-exposed animals were used as a positive control. Different doses of particulate and soluble forms were used in the study because of different LD(50) values. The results suggest that nano-copper induces hepatic dysfunction and cell death via the oxidative stress-dependent signaling cascades and mitochondrial event.

D(+) galactosamine induced oxidative and nitrosative stress-mediated renal damage in rats via NF-κB and inducible nitric oxide synthase (iNOS) pathways is ameliorated by a polyphenol xanthone, mangiferin

The present study investigated the possible protective effect of mangiferin against D(+) galactosamine (DGal)-induced nephrotoxicity. DGal intoxication increased reactive oxygen species (ROS), reactive nitrogen species and tumor necrosis factor-α (TNF-α) production and disturbed the antioxidant machineries in the kidney tissue. Mangiferin treatment post to DGal exposure reduced all these DGal-induced adverse effects. Signal transduction studies showed that DGal significantly increased the protein expression of Bax, cytochrome c, caspase 3/9 and inducible nitric oxide synthase (iNOS) in the cytosol and NF-κB in nuclear fraction. The same exposure, on the other hand, reduced the protein expression of Bcl-2 in the cytosol. Mangiferin treatment could, however, reduce the DGal-induced up-regulation of cytochrome c, NF-κB, iNOS, caspase 3/9 and alter the reciprocal regulation of Bcl-2 family proteins. Histological studies also revealed the nephroprotective effect of mangiferin against DGal induced nephrotoxicity. Combining, results suggest that mangiferin protects rat's kidney in DGal-induced oxidative/nitrosative stress and acute nephrotoxicity via its antioxidant activities.

Phytomedicinal Role of Pithecellobium dulce against CCl(4)-mediated Hepatic Oxidative Impairments and Necrotic Cell Death

Present study investigates the beneficial role of the aqueous extract of the fruits of Pithecellobium dulce (AEPD) against carbon tetrachloride (CCl₄)-induced hepatic injury using a murine model. AEPD has been found to possess free radical (DPPH, hydroxyl and superoxide) scavenging activity in cell-free system. CCl₄ exposure increased the activities of various serum maker enzymes and intracellular reactive oxygen species (ROS) production. In line with these findings, we also observed that CCl₄ intoxication increased the lipid peroxidation and protein carbonylation accompanied by decreased intracellular antioxidant defense, activity of cytochrome P450 and CYP2E1 expression. DNA fragmentation and flow cytometric analyses revealed that CCl₄ exposure caused hepatic cell death mainly via the necrotic pathway. Treatment with AEPD both pre- and post-toxin exposure protected the organ from CCl₄-induced hepatic damage. Histological findings also support our results. A well-known antioxidant vitamin C was included in this study to compare the antioxidant potency of AEPD. Combining all, results suggest that AEPD protects murine liver against CCl₄-induced oxidative impairments probably via its antioxidative property.

Protective role of a coumarin-derived schiff base scaffold against tertiary butyl hydroperoxide (TBHP)-induced oxidative impairment and cell death via MAPKs, NF-κB and mitochondria-dependent pathways

The present study investigated the antioxidant signalling mechanism of a coumarin-derived schiff base (CSB) scaffold against tert-butylhydroperoxide (TBHP) induced oxidative insult in murine hepatocytes. CSB possesses DPPH and other free radical scavenging activities. TBHP reduced cell viability and intracellular antioxidant status accompanied by an increase in intracellular ROS production in hepatocytes. TBHP also activated phospho-ERK1/2, phospho-p38 and NF-κB, altered the Bcl-2/Bad ratio, reduced mitochondrial membrane potential, released cytochrome C and activated caspase 3, suggesting that TBHP induced oxidative stress responsive cell death via apoptotic pathway. FACS analysis and DNA fragmentation studies also confirmed the apoptotic cell death in TBHP exposed hepatocytes. Treatment with CSB effectively reduced these adverse effects by preventing the oxidative insult, alteration in the redox-sensitive signalling cascades and mitochondrial events. Combining, results suggest that antioxidant property of CSB make the molecule to be a potential protective measure against oxidative insult, cytotoxicity and cell death.

Modulation of oxidative/nitrosative stress and mitochondrial protective effect of Semecarpus anacardium in diabetic rats

OBJECTIVES

Oxidative and nitrosative stress play an important role in the complications of diabetes mellitus. Free radicals are produced when there is an electron leak in the mito-chondria and a change in the mitochondrial membrane potential. The present study was undertaken to investigate the role of Semecarpus anacardium in protecting the mito-chondria by modulating the production of reactive oxygen species and reactive nitrogen species in diabetic rats.

METHODS

Diabetes was induced using streptozotocin at a dose of 50 mg/kg body weight and, starting 3 days after the induction, Semecarpus anacardium nut milk extract was administered for 21 days. The same duration of study was used for control, diabetes-induced and drug control groups, together with a group treated with metformin. After the experimental period, the animals were sacrificed and the levels of superoxide, hydrogen peroxide, nitrate and nitrite were estimated. Changes in mitochondrial membrane potential, intracellular reactive oxygen species and intracellular calcium were also determined. Confocal laser microscopic images were taken for mitochondria isolated from the liver and kidneys.

KEY FINDINGS

The results of the study revealed that Semecarpus anacardium was able to decrease the production of reactive oxygen and nitrogen species, and reverse the changes in mitochondrial membrane potential and the influx of calcium into the mitochondria.

CONCLUSIONS

The mitochondrial protective effect may be mediated by scavenging of free radicals and complexing of metal ions by virtue of the antioxidative effect of Semecarpus anacardium.

Hypoxia preconditioning by cobalt chloride enhances endurance performance and protects skeletal muscles from exercise-induced oxidative damage in rats

AIM

Training under hypoxia has several advantages over normoxic training in terms of enhancing the physical performance. Therefore, we tested the protective effect of hypoxia preconditioning by hypoxia mimetic cobalt chloride against exercise-induced oxidative damage in the skeletal muscles and improvement of physical performance.

METHOD

Male Sprague-Dawley rats were randomly divided into four groups (n=8), namely control, cobalt-supplemented, training and cobalt with training. The red gastrocnemius muscle was examined for all measurements, viz. free radical generation, lipid peroxidation, muscle damage and antioxidative capacity.

RESULTS

Hypoxic preconditioning with cobalt along with training significantly increased physical performance (33%, P<0.01) in rats compared with training-only rats. Cobalt supplementation activated cellular oxygen sensing system in rat skeletal muscle. It also protected against training-induced oxidative damage as observed by an increase in the GSH/GSSG ratio (36%, P<0.001; 28%, P<0.01 respectively) and reduced lipid peroxidation (15%, P<0.01; 31%, P<0.01 respectively) in both trained and untrained rats compared with their respective controls. Cobalt supplementation along with training enhanced the expression of antioxidant proteins haem oxygenase-1 (HO-1; 1.2-fold, P<0.05) and metallothionein (MT; 4.8-fold, P<0.001) compared with training only. A marked reduction was observed in exercise-induced muscle fibre damage as indicated by decreased necrotic muscle fibre, decreased lipofuscin content of muscle and plasma creatine kinase level (16%, P<0.01) in rats preconditioned with cobalt.

CONCLUSION

Our study provides strong evidence that hypoxic preconditioning with cobalt chloride enhances physical performance and protects muscle from exercise-induced oxidative damage via GSH, HO-1 and MT-mediated antioxidative capacity.

Hypoxic preconditioning facilitates acclimatization to hypobaric hypoxia in rat heart

Objectives

Acute systemic hypoxia induces delayed cardioprotection against ischaemia-reperfusion injury in the heart. As cobalt chloride (CoCl2) is known to elicit hypoxia-like –responses, it was hypothesized that this chemical would mimic the preconditioning effect and facilitate acclimatization to hypobaric hypoxia in rat heart.

Methods

Male Sprague-Dawley rats treated with distilled water or cobalt chloride (12.5 mg Co/kg for 7 days) were exposed to simulated altitude at 7622 m for different time periods (1, 2, 3 and 5 days).

Key findings

Hypoxic preconditioning with cobalt appreciably attenuated hypobaric hypoxia-induced oxidative damage as observed by a decrease in free radical (reactive oxygen species) generation, oxidation of lipids and proteins. Interestingly, the observed effect was due to increased expression of the antioxidant proteins hemeoxygenase and metallothionein, as no significant change was observed in antioxidant enzyme activity. Hypoxic preconditioning with cobalt increased hypoxia-inducible factor 1α (HIF-1α) expression as well as HIF-1 DNA binding activity, which further resulted in increased expression of HIF-1 regulated genes such as erythropoietin, vascular endothelial growth factor and glucose transporter. A significant decrease was observed in lactate dehydrogenase activity and lactate levels in the heart of preconditioned animals compared with non-preconditioned animals exposed to hypoxia.

Conclusions

The results showed that hypoxic preconditioning with cobalt induces acclimatization by up-regulation of hemeoxygenase 1 and metallothionein 1 via HIF-1 stabilization.

Contribution of type 1 diabetes to rat liver dysfunction and cellular damage via activation of NOS, PARP, IkappaBalpha/NF-kappaB, MAPKs, and mitochondria-dependent pathways: Prophylactic role of arjunolic acid

Diabetic mellitus, a chronic metabolic disorder, is one of the most important health problems in the world, especially in developing countries. Our earlier investigations reported the beneficial action of arjunolic acid (AA) against streptozotocin-mediated type 1 hyperglycemia. We have demonstrated that AA possesses protective roles against drug- and chemical- (environmental toxins) induced hepatotoxicity. Liver is the main organ of detoxification. The purpose of this study was to explore whether AA plays any protective role against hyperglycemic hepatic dysfunctions and, if so, what molecular pathways it utilizes for the mechanism of its protective action. In experimental rats, type 1 hyperglycemia was induced by streptozotocin. AA was administered orally at a dose of 20mg/kg body wt both before and after diabetic induction. An insulin-treated group was included in the study as a positive control for type 1 diabetes. Hyperglycemia caused a loss in body weight, reduction in serum insulin level, and increased formation of HbA(1C) as well as advanced glycation end products (AGEs). Elevated levels of serum ALT and ALP, increased production of ROS and RNS, increased lipid peroxidation, increased 8-OHdG/2-dG ratio, and decreased GSH content and cellular antioxidant defense established the hyperglycemic liver dysfunction. Activation of iNOS, IkappaBalpha/NF-kappaB, and MAPK pathways as well as signals from mitochondria were found to be involved in initiating apoptotic cell death. Hyperglycemia caused overexpression of PARP, reduction in intracellular NAD as well as ATP level, and increased DNA fragmentation in the liver tissue of the diabetic animals. Results of immunofluorescence (using anti-caspase-3 and anti-Apaf-1 antibodies), DAPI/PI staining, and DNA ladder formation and information obtained from FACS analysis confirmed the apoptotic cell death in diabetic liver tissue. Histological studies also support the experimental findings. AA treatment prevented or ameliorated the diabetic liver complications and apoptotic cell death. The effectiveness of AA in preventing the formation of ROS, RNS, HbA(1C), AGEs, and oxidative stress signaling cascades and protecting against PARP-mediated DNA fragmentation can speak about its potential uses for diabetic patients.

Impact of exercise training on oxidative stress in individuals with a spinal cord injury

Individuals with a spinal cord injury (SCI) have an increased cardiovascular risk. We hypothesize that (anti)oxidative imbalance is associated with the increased cardiovascular risk in SCI, while exercise can reverse this status. The aim of the study is to compare baseline levels of oxidative stress and antioxidative capacity between individuals with SCI and able-bodied (AB) subjects, and to assess acute and long-term effects of functional electrical stimulation (FES) exercise on oxidative stress and antioxidative capacity in SCI. Venous blood was taken from subjects with an SCI (n = 9) and age- and gender-matched AB subjects (n = 9) to examine oxidative stress through malondialdehyde (MDA) levels, while superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzyme levels represented anti-oxidative capacity. Subsequently, subjects with an SCI performed an 8-week FES exercise training period. Blood was taken before and after the first exercise bout and after the last FES session to examine the acute and chronic effect of FES exercise, respectively. Baseline levels of MDA, SOD and GPx were not different between individuals with SCI and AB subjects. SCI demonstrated a correlation between initial fitness level and MDA (R = -0.83, P = 0.05). MDA, SOD and GPx levels were neither altered by a single FES exercise bout nor by 8 weeks FES training. In conclusion, although individuals with an SCI demonstrate a preserved (anti)oxidative status, the correlation between fitness level and (anti)oxidative balance suggests that higher fitness levels are related to improved (anti)oxidative status in SCI. Nonetheless, the FES exercise stimulus was insufficient to acutely or chronically change (anti)oxidative status in individuals with an SCI.

Taurine protects acetaminophen-induced oxidative damage in mice kidney through APAP urinary excretion and CYP2E1 inactivation

Acute exposure of acetaminophen (APAP), a widely used analgesic and antipyretic drug, causes severe renal damage and no specific agent has been reported so far that plays any beneficial role in this organ pathophysiology. In the present study, the protective role of taurine on APAP-induced nephrotoxicity was investigated in mice. In order to induce acute nephrotoxicity, APAP was administered at a single dose of 2g/kg body weight orally to male adult albino mice of Swiss strain. APAP exposure for 24h significantly increased plasma level of blood urea nitrogen (BUN), creatinine, uric acid, TNF-alpha, NO production, urinary gamma-glutamyl transpeptidase (gamma-GT) activity, total urinary protein and urinary glucose level accompanied by a decrease in Na(+)-K(+)-ATPase activity. Moreover, APAP administration significantly increased MDA, protein carbonylation, GSSG level, intracellular ROS production and cytochrome P450 enzyme (CYPP450) activity. The same exposure decreased GSH level, ferric reducing/antioxidant power (FRAP) as well as the activities of antioxidant enzymes indicating that APAP-induced renal damage was mediated through oxidative stress. Besides, APAP exposure significantly reduced mitochondrial membrane potential and induced up-regulation of CYP2E1 in renal tissues although JNK did not play any significant role in this APAP-induced renal pathophysiology. Caspase 9/3 immunoblot and DNA fragmentation analyses showed that APAP-induced renal cell damage was mostly necrotic in nature, although some apoptosis also occurred simultaneously. Taurine treatment both pre and post (150 mg/kg body weight for 3 days, orally) to APAP exposure, however, significantly reduced APAP-induced nephrotoxicity through its antioxidant properties, urinary excretion of APAP and suppression of CYP2E1. Results suggest that taurine might be a potential therapeutic candidate against APAP-induced acute nephrotoxicity.

Streptozotocin induced activation of oxidative stress responsive splenic cell signaling pathways: protective role of arjunolic acid

Present study investigates the beneficial role of arjunolic acid (AA) against the alteration in the cytokine levels and simultaneous activation of oxidative stress responsive signaling pathways in spleen under hyperglycemic condition. Diabetes was induced by injection of streptozotocin (STZ) (at a dose of 70 mg/kg body weight, injected in the tail vain). STZ administration elevated the levels of IL-2 as well as IFN-gamma and attenuated the level of TNF-alpha in the sera of diabetic animals. In addition, hyperglycemia is also associated with the increased production of intracellular reactive intermediates resulting with the elevation in lipid peroxidation, protein carbonylation and reduction in intracellular antioxidant defense. Investigating the oxidative stress responsive cell signaling pathways, increased expressions (immunoreactive concentrations) of phosphorylated p65 as well as its inhibitor protein phospho IkappaBalpha and phosphorylated mitogen activated protein kinases (MAPKs) have been observed in diabetic spleen tissue. Studies on isolated splenocytes revealed that hyperglycemia caused disruption of mitochondrial membrane potential, elevation in the concentration of cytosolic cytochrome c as well as activation of caspase 3 leading to apoptotic cell death. Histological examination revealed that diabetic induction depleted the white pulp scoring which is in agreement with the reduced immunological response. Treatment with AA prevented the hyperglycemia and its associated pathogenesis in spleen tissue. Results suggest that AA might act as an anti-diabetic and immunomodulatory agent against hyperglycemia.

Acetaminophen induced renal injury via oxidative stress and TNF-alpha production: therapeutic potential of arjunolic acid

Acetaminophen (APAP) causes acute and chronic renal failure. The mechanisms leading to hepatic injury have been extensively studied, but the molecular mechanisms regarding APAP-induced nephro-toxicity are poorly defined. In earlier studies, we have demonstrated that arjunolic acid (AA) possesses protective roles against chemically induced organ pathophysiology. The purpose of the present study was to explore whether AA plays any protective role against APAP induced acute renal toxicity; and if so, what pathways it utilizes for the mechanism of its protective action. Exposure of rats with a nephro-toxic dose of APAP altered a number of biomarkers (like blood urea nitrogen and serum creatinine levels, etc.) related to renal oxidative stress, decreased antioxidant activity, elevated renal tumor necrosis factor-alpha and nitric oxide levels. AA treatment both pre- and post to APAP exposure protected the alteration of these biomarkers, compensated deficits in the antioxidant defense mechanisms, and suppressed lipid peroxidation in renal tissue. Investigating the inherent molecular signaling of this pathophysiology and its protection, we found that the mitochondrial pathway was not activated during APAP-induced cell death as no dissipation of mitochondrial membrane potential or release of cytochrome C was detected in the respective experiments. Our experimental evidence suggests that APAP-induced nephro-toxicity is a caspase-dependent process that involves activation of caspase-9 and caspase-3 in the absence of cytosolic cytochrome C release. These results provide evidence that inhibition of NO overproduction and maintenance of intracellular antioxidant status may play a pivotal role in the protective effects of AA against APAP-induced renal damage. AA represents a potential therapeutic option to protect renal tissue from the detrimental effects of acute acetaminophen overdose.