Circadian (about 24-hour) variation in malondialdehyde content and catalase activity of mouse erythrocytes

Metal and oxidative potential exposure through particle inhalation and oxidative stress biomarkers: a 2-week pilot prospective study among Parisian subway workers

OBJECTIVE

In this pilot study on subway workers, we explored the relationships between particle exposure and oxidative stress biomarkers in exhaled breath condensate (EBC) and urine to identify the most relevant biomarkers for a large-scale study in this field.

METHODS

We constructed a comprehensive occupational exposure assessment among subway workers in three distinct jobs over 10 working days, measuring daily concentrations of particulate matter (PM), their metal content and oxidative potential (OP). Individual pre- and post-shift EBC and urine samples were collected daily. Three oxidative stress biomarkers were measured in these matrices: malondialdehyde (MDA), 8-hydroxy-2'deoxyguanosine (8-OHdG) and 8-isoprostane. The association between each effect biomarker and exposure variables was estimated by multivariable multilevel mixed-effect models with and without lag times.

RESULTS

The OP was positively associated with Fe and Mn, but not associated with any effect biomarkers. Concentration changes of effect biomarkers in EBC and urine were associated with transition metals in PM (Cu and Zn) and furthermore with specific metals in EBC (Ba, Co, Cr and Mn) and in urine (Ba, Cu, Co, Mo, Ni, Ti and Zn). The direction of these associations was both metal- and time-dependent. Associations between Cu or Zn and MDAEBC generally reached statistical significance after a delayed time of 12 or 24 h after exposure. Changes in metal concentrations in EBC and urine were associated with MDA and 8-OHdG concentrations the same day.

CONCLUSION

Associations between MDA in both EBC and urine gave opposite response for subway particles containing Zn versus Cu. This diverting Zn and Cu pattern was also observed for 8-OHdG and urinary concentrations of these two metals. Overall, MDA and 8-OHdG responses were sensitive for same-day metal exposures in both matrices. We recommend MDA and 8-OHdG in large field studies to account for oxidative stress originating from metals in inhaled particulate matter.

Voluntary wheel-running improved pulmonary fibrosis by reducing epithelial mesenchymal transformation

AIMS

Pulmonary fibrosis seriously affects the health and life quality of patients. Exercise has been shown to have anti-inflammatory and antioxidant effects, but its effect on pulmonary fibrosis is unclear. In this study, the effect and mechanism of exercise on pulmonary fibrosis induced by paraquat were detected.

MAIN METHODS

Three data sets were retrieved from GEO data. The biological significance of DEGs generation was determined by GO, KEGG, GSEA, and PPI. Thirty male BALB/C mice were randomly divided into control group, model group and exercise group. H&E staining, Masson staining, Immunohistochemistry and Western blot were used to explore the results. The levels of SOD, CAT, MDA, and GSH in lung tissue were analyzed with detection kits. The levels of inflammatory factors in serum and BALF were measured by ELISA.

KEY FINDINGS

Compared with the control group, the infiltration of inflammatory cells and fibrotic lesions were increased in the model group. Compared with the model group, voluntary wheel-running reducing the EMT of alveolar epithelial cells, the activation of the Wnt/β-catenin signaling pathway and the level of oxidative distress. Moreover, compared to model group, the serum IL-4, IL-10 and IFN-γ were increased, while the serum CXCL1 were decreased, while the levels of CXCL1, IL-6, IL-10, TNF-α and IFN-γ in the bronchoalveolar lavage fluid were decreased in exercise group.

SIGNIFICANCE

Voluntary wheel-running reduced inflammatory infiltration and upregulated the expression of antioxidative distress proteins, further to improve the degree of EMT, and ultimately alleviated paraquat induced pulmonary fibrosis.

Rhythm and ROS: Hepatic Chronotherapeutic Features of Grape Seed Proanthocyanidin Extract Treatment in Cafeteria Diet-Fed Rats

Polyphenols play a key role in the modulation of circadian rhythms, while the cafeteria diet (CAF) is able to perturb the hepatic biological rhythm and induce important ROS production. Consequently, we aimed to elucidate whether grape seed proanthocyanidin extract (GSPE) administration recovers the CAF-induced hepatic antioxidant (AOX) misalignment and characterize the chronotherapeutic properties of GSPE. For this purpose, Fischer 344 rats were fed a standard diet (STD) or a CAF and concomitantly treated with GSPE at two time-points (ZT0 vs. ZT12). Animals were euthanized every 6 h and the diurnal rhythms of hepatic ROS-related biomarkers, hepatic metabolites, and AOX gene expression were examined. Interestingly, GSPE treatment was able to recover the diurnal rhythm lost due to the CAF. Moreover, GSPE treatment also increased the acrophase of Sod1, as well as bringing the peak closer to that of the STD group. GSPE also corrected some hepatic metabolites altered by the CAF. Importantly, the differences observed at ZT0 vs. ZT12 due to the time of GSPE administration highlight a chronotherapeutic profile on the proanthocyanin effect. Finally, GSPE could also reduce diet-induced hepatic oxidative stress not only by its ROS-scavenging properties but also by retraining the circadian rhythm of AOX enzymes.

The effect of light regime and time of slaughter in broiler on broiler performance, liver antioxidant status, and expression of genes related to peptide absorption in the jejunum and melatonin synthesis in the brain

This study aimed to assess the effects of light regime and time of slaughter on primal cut and organ weights, peptide transporter 1 (PEPT1) gene expression in the jejunum, arylalkylamine N-acetyltransferase (AANAT) gene expression in the brain, and liver oxidant/antioxidant status in broilers aged 37 days. The experiment was conducted in a factorial completely randomized design, with two light regimes (intermittent light varying according to bird age and continuous light under an 18 h light/6 h dark photoperiod) and four times of slaughter (2:00, 8:00, 14:00 and 20:00 h). There was an interaction effect on PEPT1 and AANAT expression, lipid and protein oxidation and superoxide dismutase (SOD) activity. In both light regimes, PEPT1 expression responded cubically to slaughter time. In the continuous light group, PEPT1 expression was highest in birds slaughtered at 2:00 and 14:00 h, whereas, in the intermittent light treatment, expression was highest at 8:00 h. In the continuous light regime, AANAT expression had a cubic relationship with time of slaughter, with the greatest values recorded at 20:00 h. In the intermittent light regime, slaughter time showed a cubic effect on lipid oxidation, which was highest at 8:00 h. In the continuous light group, there was a cubic effect on nitrite concentration, lipid oxidation, protein oxidation, and SOD activity; nitrite levels, lipid oxidation, and protein oxidation were highest and SOD activity was lowest in birds slaughtered at 14:00 h. Time of slaughter influenced catalase activity, which responded cubically; catalase activity was lowest at 8:00 and 14:00 h. This study is the first to demonstrate that PEPT1 expression in the jejunum of broilers follows a diurnal rhythm and varies according to light regime. The results also suggest that mainly continuous lighting and slaughter at 14:00 h when the animals are possibly more active may be more stressful to broilers.

Diurnal efficacy of alpha-lipoic acid/nifedipine/glimepiride combination mitigates diabetic neuropathies in rats

OBJECTIVES

Time-dependent effects of alpha-lipoic acid/nifedipine/glimepiride combination on diabetic neuropathies were investigated in rats. 7 groups (N=9) of rats were used.

MATERIALS AND METHODS

First and second groups were apparently normal and diabetic rats respectively, and were administered 1 mL/kg distilled water. The rest of the groups were diabetic and administered 10 mg/kg glimepiride at night-time (8:00 pm). Groups 4-7 were administered additional 20 mg/kg nifedipine at morning-time (8:00 am), while groups 5-7 were also administered 100 mg/kg alpha-lipoic acid (ALA) in the morning, afternoon and night-time respectively (8:00 am, 2:00 pm and 8:00 pm). During the 28 days of oral treatment, paw pressure, tail immersion and motor coordination tests were conducted. The rats were euthanized on the 29^th day after a charcoal meal. The small intestines were excised to determine intestinal transit while the brain was collected, homogenised and used to determine levels of oxidative stress.

RESULTS

Data show that treatment with ALA at 8:00 am or 2:00 pm significantly (p ≤ 0.01) produced a delay in the onset and improved prognosis of neuropathies. Treatment with ALA at 8:00 pm prevented manifestation of neuropathies throughout the study with positive antioxidant effects.

CONCLUSION

Time-dependent ALA treatment in combination with nifedipine and glimepiride should be studied in humans with an approximately similar circadian timing. This may provide additional clinical therapeutic options for diabetic neuropathies.

Redox changes in obesity, metabolic syndrome, and diabetes

"Life is an instantaneous encounter of circulating matter and flowing energy" (Jean Giaja, Serbian physiologist), is one of the most elegant definitions not only of life but the relationship of redox biology and metabolism. Their evolutionary liaison has created inseparable yet dynamic homeostasis in health, which, when disrupted, leads to disease. This interconnection is even more pertinent today, in an era of increasing metabolic diseases of epidemic proportions such as obesity, metabolic syndrome, and diabetes. Despite great advances in understanding the molecular mechanisms of redox and metabolic regulation, we face significant challenges in preventing, diagnosing, and treating metabolic diseases. The etiological association and temporal overlap of these syndromes present significant challenges for the discrimination of appropriate clinical biomarkers for diagnosis, treatment, and outcome prediction. These multifactorial, multiorgan metabolic syndromes with complex etiopathogenic mechanisms are accompanied by disturbed redox equilibrium in target tissues and circulation. Free radicals and reactive species are considered both a causal factor and a consequence of disease status. Thus, determining the subtypes and levels of free radicals and reactive species, oxidatively damaged biomolecules (lipids, proteins, and nucleic acids) and antioxidant defense components as well as redox-sensitive transcription factors and fluxes of redox-dependent metabolic pathways will help define existing and establish novel redox biomarkers for stratifying metabolic diseases. This review aims to discuss diverse redox/metabolic aspects in obesity, metabolic syndrome, and diabetes, with the imperative to help establish a platform for emerging and future redox-metabolic biomarkers research in precision medicine. Future research warrants detailed investigations into the status of redox biomarkers in healthy subjects and patients, including the use of emerging 'omic' profiling technologies (e.g., redox proteomes, lipidomes, metabolomes, and transcriptomes), taking into account the influence of lifestyle (diet, physical activity, sleep, work patterns) as well as circadian ~24h fluctuations in circulatory factors and metabolites.

The circadian clock and metabolic homeostasis: entangled networks

The circadian clock exerts an important role in systemic homeostasis as it acts a keeper of time for the organism. The synchrony between the daily challenges imposed by the environment needs to be aligned with biological processes and with the internal circadian clock. In this review, it is provided an in-depth view of the molecular functioning of the circadian molecular clock, how this system is organized, and how central and peripheral clocks communicate with each other. In this sense, we provide an overview of the neuro-hormonal factors controlled by the central clock and how they affect peripheral tissues. We also evaluate signals released by peripheral organs and their effects in the central clock and other brain areas. Additionally, we evaluate a possible communication between peripheral tissues as a novel layer of circadian organization by reviewing recent studies in the literature. In the last section, we analyze how the circadian clock can modulate intracellular and tissue-dependent processes of metabolic organs. Taken altogether, the goal of this review is to provide a systemic and integrative view of the molecular clock function and organization with an emphasis in metabolic tissues.

Molecular regulation of brain metabolism underlying circadian epilepsy

Extensive study has demonstrated that epilepsy occurs with greater frequency at certain times in the 24-h cycle. Although these findings implicate an overlap between the circadian rhythm and epilepsy, the molecular and cellular mechanisms underlying this circadian regulation are poorly understood. Because the 24-h rhythm is generated by the circadian molecular system, it is not surprising that this system comprised of many circadian genes is implicated in epilepsy. We summarized evidence in the literature implicating various circadian genes such as Clock, Bmal1, Per1, Rev-erb⍺, and Ror⍺ in epilepsy. In various animal models of epilepsy, the circadian oscillation and the steady-state level of these genes are disrupted. The downstream pathway of these genes involves a large number of metabolic pathways associated with epilepsy. These pathways include pyridoxal metabolism, the mammalian target of rapamycin pathway, and the regulation of redox state. We propose that disruption of these metabolic pathways could mediate the circadian regulation of epilepsy. A greater understanding of the cellular and molecular mechanism of circadian regulation of epilepsy would enable us to precisely target the circadian disruption in epilepsy for a novel therapeutic approach.

Chronopharmacology of the alpha-lipoic acid/nifedipine/glimepiride combination in the amelioration of retinopathy in rats

Time of drug administration affects both the kinetics and dynamics of medications. This study investigated diurnal efficacy of alpha-lipoic acid (ALA), nifedipine, and glimepiride combination in the treatment of diabetic retinopathy. The study design comprised seven groups of rats, with groups 1 and 2 serving as non-diabetic and diabetic controls, respectively, receiving 1 ml/kg distilled water. All other groups were diabetic, and received 10 mg/kg glimepiride at 20:00 h. Groups 4-7 also received 20 mg/kg nifedipine at 08:00 h. In addition, groups 5-7 received 100 mg/kg ALA at 08:00 h, 14:00 h, and 20:00 h, respectively. Oral drug administration was for 28 days during which fasting and random blood glucose sampling were done weekly at 07:30 h and 13:30 h, respectively. On the 29^th day, rats were euthanized; blood was collected via the jugular veins for determination of serum ocular markers like magnesium, cholesterol, and triglyceride. Furthermore, the eyes were excised and their relative organ/body weight ratios determined. The right eyes were persevered in phosphate buffer for homogenization and determination of retina antioxidant profile (MDA, SOD, CAT, GSH), while the left eyes were preserved in formalin for histological examination. Results showed that treatment with ALA and glimepiride at 20:00 h along with nifedipine at 08:00 h resulted in better prognosis than other treatment groups and with improved glycemic control. Also, all their serum markers for retinopathy, organ weight, and histology did not differ significantly from that of the non-diabetic rats. Findings imply that diurnal efficacy in alpha-lipoic acid, nifedipine and glimepiride combination ameliorates diabetic retinopathy in rats and may be beneficial in the treatment of diabetic retinopathy.

Effect of Ramadan intermittent fasting on cognitive, physical and biochemical responses to strenuous short-term exercises in elite young female handball players

The present study aimed to assess the effect of Ramadan intermittent fasting (RF) on cognitive and physical performance and biochemical responses to specific exercises in elite young female handball players. Twelve athletes participated in three experimental sessions: one week before Ramadan (BR), during the first week of Ramadan (FWR) and during the last week of Ramadan (LWR). The present crossover study was carried out in Tunisia during the 2013 Ramadan month lasting from 9 July to 7 august. During each session, a battery of tests was performed as follow: Hooper index, vigilance test (VT), Epworth sleepiness scale (ESS), five jump test (5-JT), modified agility T-test (MAT), maximal standing ball-throw velocity test (MSBVT) and Running-based Anaerobic Sprint (RAST) Test. Rating of perceived exertion (RPE) was recorded immediately after the RAST. Blood samples were collected before and after exercises during each session. The results showed that ESS scores were higher during LWR than BR (p < 0.05). Moreover, MSBVT time decreased (p < 0.05) during LWR, therefore performance enhanced. The power of three final sprints from the RAST decreased significantly only during LWR compared to BR (p < 0.05). RAST fatigue index and RPE scores were higher during LWR more than BR (p < 0.05). The results showed also that hematological measures (i.e., red blood cells, hemoglobin and hematocrit), plasma osmolarity and energetic markers were unaffected by RF. Biomarkers of muscle damage were higher after the RAST only during LWR compared to BR (p < 0.01 for all). In conclusion, RF increased ESS and decreased RAST performances associated with higher muscle damage and fatigue, especially at LWR. These previous alterations could be attributed to disturbances of sleep and circadian rhythms rather than nutritional deficiency or dehydratation.

Immune-toxicity effects of scorpion venom on the hypothalamic pituitary adrenal axis during rest and activity phases in a rodent model

Scorpion venom is a complex mixture of peptides and proteins, rich in toxins. Its toxicological effects are related to central disruptions and autonomic disturbances, organ failure, as well as an excessive systemic inflammatory response. Since the role of the hypothalamic pituitary adrenal (HPA) axis is central in the neuroendocrine-immunological axis, the purpose of this study was, therefore, to examine the immunotoxic effect of Androctonus australis hector (Aah) venom on HPA-axis in synchronised-mice model. Taking into account the circadian activity of the HPA-axis, the variations of adrenocorticotropic hormone and corticosterone plasma levels, oxidative stress as well as inflammatory markers in cerebral, hypothalamic and adrenal tissue homogenates were investigated during the rest and activity phases of animals. Histopathology study was also performed. Results showed that Aah venom activated the HPA axis. This response seems to be dependent on time of envenomation, as a higher hormone levels were more operative during the active phase than in the rest phase when compared to time-matched control. The local toxicity-effects following Aah envenomation revealed an imbalance in oxidative stress with a higher antioxidant defences in darkness hypothalamic and cerebral tissues. Furthermore, there were significantly higher levels in vascular permeability in hypothalamic and cerebral tissues accompanied by a concomitant increase in immune-cell infiltration and/or activation as shown by expression of CD68 and myeloperoxidase activity during the active phase compared with the rest phase. Overall results suggested that Aah venom had a toxic impact on different HPA-axis areas and the effect varies according to the time of envenomation.

Effects of silver nanoparticles functionalized with Cornus mas L. extract on architecture and apoptosis in rat testicle

Aim: To assess ultrastructural changes, alterations in matrix metalloproteinase activity and apoptosis induced by silver nanoparticles (AgNPs) in the rat testicle. Materials & methods: For 45 days, two groups of animals received different doses of AgNPs (0.8 and 1.5 mg/kg b.w.), and a control group was given the buffer used as vehicle for AgNPs. At 7 and 15 days post-treatment, transmission electron microscopy, TUNEL assay, evaluation of NFkB, pNFkB, p53, Bcl-2 and Nrf2 expressions were performed on the removed testes. Results: Transmission electron microscopy revealed severe ultrastructural changes of interstitial tissue and seminiferous epithelium sustained by positive signal for apoptosis. The promatrix metalloproteinase-2 activity and NFkB, Bcl-2 expressions were increased, mainly at 7 days. Conclusion: AgNPs induced severe cell lesions identified even a long time after the exposure.

Neuroprotection afforded by circadian regulation of intracellular glutathione levels: A key role for miRNAs

Circadian rhythms are approximately 24-h oscillations of physiological and behavioral processes that allow us to adapt to daily environmental cycles. Like many other biological functions, cellular redox status and antioxidative defense systems display circadian rhythmicity. In the central nervous system (CNS), glutathione (GSH) is a critical antioxidant because the CNS is extremely vulnerable to oxidative stress; oxidative stress, in turn, causes several fatal diseases, including neurodegenerative diseases. It has long been known that GSH level shows circadian rhythm, although the mechanism underlying GSH rhythm production has not been well-studied. Several lines of recent evidence indicate that the expression of antioxidant genes involved in GSH homeostasis as well as circadian clock genes are regulated by post-transcriptional regulator microRNA (miRNA), indicating that miRNA plays a key role in generating GSH rhythm. Interestingly, several reports have shown that alterations of miRNA expression as well as circadian rhythm have been known to link with various diseases related to oxidative stress. A growing body of evidence implicates a strong correlation between antioxidative defense, circadian rhythm and miRNA function, therefore, their dysfunctions could cause numerous diseases. It is hoped that continued elucidation of the antioxidative defense systems controlled by novel miRNA regulation under circadian control will advance the development of therapeutics for the diseases caused by oxidative stress.

Potential neuroprotective effect of Anakinra in spinal cord injury in an in vivo experimental animal model

OBJECTIVE

To evaluate the therapeutic effects of inhibiting interleukin-1 beta (IL-1 beta) in vivo using Anakinra in an experimental model of spinal cord injury (SCI).

METHODS

All experimental procedures were performed in the animal laboratory of Ankara Education and Research Hospital, Ankara, Turkey between August 2012 and May 2014. The SCI was induced by applying vascular clips to the dura via a 4-level T5-T8 laminectomy. Fifty-four rats were randomized into the following groups: controls (n = 18), SCI + saline (n = 18), and SCI + Anakinra (n = 18). Spinal cord samples were obtained from animals in both SCI groups at one, 6, and 24 hours after surgery (n = 6 for each time point). Spinal cord tissue and serum were extracted, and the levels of IL-1 beta, malondialdehyde, glutathione peroxidase, superoxide dismutase, and catalase were analyzed. Furthermore, histopathological evaluation of the tissues was performed.

RESULTS

The SCI in rats caused severe injury characterized by edema, neutrophil infiltration, and cytokine production followed by recruitment of other inflammatory cells, lipid peroxidation, and increased oxidative stress. After SCI, tissue and serum IL-1 beta levels were significantly increased, but were significantly decreased by Anakinra administration. Following trauma, glutathione peroxidase, superoxide dismutase, and catalase levels were decreased; however, Anakinra increased the activity of these antioxidant enzymes. Malondialdehyde levels were increased after trauma, but were unaffected by Anakinra. Histopathological analysis showed that Anakinra effectively protected the spinal cord tissue from injury.

CONCLUSION

Treatment with Anakinra reduces inflammation and other tissue injury events associated with SCI.