Antioxidant intervention attenuates oxidative stress in children and teenagers with Down syndrome

We previously demonstrated that systemic oxidative stress is present in Down syndrome (DS) patients. In the present study we investigated the antioxidant status in the peripheral blood of DS children and teenagers comparing such status before and after an antioxidant supplementation. Oxidative stress biomarkers were evaluated in the blood of DS patients (n = 21) before and after a daily antioxidant intervention (vitamin E 400 mg, C 500 mg) during 6 months. Healthy children (n = 18) without DS were recruited as control group. The activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), gamma-glutamyltransferase (GGT), glucose-6-phosphate dehydrogenase (G6PD) and myeloperoxidase (MPO), as well as the contents of reduced glutathione (GSH), uric acid, vitamin E, thiobarbituric acid reactive substances (TBARS), and protein carbonyls (PC) were measured. Before the antioxidant therapy, DS patients presented decreased GST activity and GSH depletion; elevated SOD, CAT, GR, GGT and MPO activities; increased uric acid levels; while GPx and G6PD activities as well as vitamin E and TBARS levels were unaltered. After the antioxidant supplementation, SOD, CAT, GPx, GR, GGT and MPO activities were downregulated, while TBARS contents were strongly decreased in DS. Also, the antioxidant therapy did not change G6PD and GST activities as well as uric acid and PC levels, while it significantly increased GSH and vitamin E levels in DS patients. Our results clearly demonstrate that the antioxidant intervention with vitamins E and C attenuated the systemic oxidative damage present in DS patients.     

Antioxidant enzymes in cerebral cortex of immature rats following experimentally-induced seizures: upregulation of mitochondrial MnSOD (SOD2)

We have recently demonstrated the evidence of oxidative stress in brain of immature rats during seizures induced by dl-homocysteic acid (dl-HCA). The aim of the present study was to investigate the antioxidant defense mechanisms under these conditions. Seizures were induced in immature 12-day-old rats by bilateral icv infusion of dl-HCA (600 nmol/side), and the activities of the main antioxidant enzymes were examined in supernatants of the cerebral cortex during the acute phase of seizures and at several periods of survival, up to 5 weeks, following these seizures. In control animals individual antioxidant enzymes revealed different changes during the studied postnatal period (PD 12 till PD 47). Total superoxide dismutase (SOD), CuZn SOD (SOD1), Mn SOD (SOD2) and glutathione peroxidase (GPX) activities were increasing while, catalase activity decreased and the activity of glutathione reductase (GR) remained unchanged. In HCA-treated animals, the activity of total SOD, SOD1 and particularly SOD2 significantly increased at 20 h and 6 days of survival. Importantly, upregulation of SOD2 was also confirmed in mitochondria at the protein level by immunoblotting. The activities of other antioxidant enzymes including catalase and GPX did not significantly differ upon HCA treatment from the appropriate controls at any of the studied time intervals. The pronounced and selective upregulation of SOD2 points to enhanced ROS levels in the mitochondrial matrix. This may be associated with inhibition of respiratory chain complex I that we have demonstrated in our previous studies. The present findings suggest that oxidative stress occurring in the brain of immature rats during and following the seizures induced by dl-HCA is apparently due to both the increased free radical production and the limited antioxidant defense.     

Persistence of the benefit of an antioxidant therapy in children and teenagers with Down syndrome

This study examined the effect of an antioxidant intervention in biomarkers of inflammation and oxidative stress (OS) in the blood of Down syndrome (DS) children and teenagers during four different stages. A control group was composed by healthy children (n = 18), assessed once, and a Down group composed by DS patients (n = 21) assessed at the basal period (t₀), as well as after 6 months of antioxidant supplementation (t₁), after 12 months (after interruption of the antioxidant intervention for 6 months) (t₂), and again after further 6 months of antioxidant supplementation (t₃). Biomarkers of inflammation (myeloperoxidase activity – MPO and levels of IL-1β and TNF-α) and OS (thiobarbituric acid reactive substances – TBARS, protein carbonyls – PC), reduced glutathione (GSH), uric acid (UA) and vitamin E levels, as well as antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) and gamma-glutamyltransferase (GGT) activities, were measured after each period. After the antioxidant supplementation, the activities of SOD, CAT, GPx, GR, GGT and MPO were downregulated, while TBARS contents were strongly decreased, the contents of GSH and vitamin E were significantly increased, and no changes in G6PD and GST activity as well as in UA and PC levels were detected. After the interruption of the antioxidant therapy for 6 months, DS patients showed elevated GPx and GGT activities and also elevated UA and TBARS levels. No changes in SOD, CAT, GR, GST, G6PD and MPO activities as well as in GSH, vitamin E, PC, TNF-α and IL-1β levels were detected. The results showed that the antioxidant intervention persistently attenuated the systemic oxidative damage in DS patients even after a relatively long period of cessation of the antioxidant intervention.     

Endogenous antioxidants and rate of malondialdehyde formation in central and peripheral nervous systems

The contents of ascorbic acid (AH₂), dehydroascorbate, and glutathione (GSH), and the activities of catalase, glutathione peroxidase, glutathione reductase (GR), and superoxide dismutase (SOD) were determined in whole homogenates of spinal cord and sciatic nerve of greyhound dogs. The effect of incubation of homogenates with or without superoxide or free radical generating systems on AH₂ and GSH content and SOD activity was compared with the rate of malondialdehyde (MDA) formation in both tissues. Significantly higher content of GSH and enzymatic activities of SOD and GR in spinal cord were found compared with sciatic nerve. During spontaneous or induced peroxidation the content of AH₂ and GSH and SOD activity decreased similarly both in spinal cord and in the peripheral nerve. Yet MDA formation was significantly faster in spinal cord compared with sciatic nerve incubated with or without the peroxidation-promoting system. We conclude that the spinal cord, in spite of a higher content of some endogenous antioxidants, is much more susceptible to peroxidative changes for a yet unknown reason.     

The effect of chronic nicotine and withdrawal on intra-axonal transport of acetylcholine and related enzymes in sciatic nerve of the rat

Summary The content of acetylcholine (ACh) and activities of the cholinergic enzymes choline acetyltransferase (CAT) and ACh-esterase (AChE) were studied in intact and crushed rat sciatic nerve afterchronic nicotine administration andwithdrawal 2 days before the final experiment. Nicotine was given in the drinking water during 8–10 weeks and the final dose reached was about 8 mg/kg/day, i.e. equivalent to that of the heavy cigarette smoker.In thechronic nicotine group, ACh levels and AChE activity of uncrushed nerve were significantly decreased as compared to the controls. The accumulation of ACh and AChE proximal to a single crush was also somewhat decreased, but significant only for AChE at 18 hours postoperatively. Afterwithdrawal of nicotine for 2 days the ACh content of both uncrushed and 12 hours crushed nerves were further decreased, while AChE was instead increased to control (uncrushed) or even supranormal (18-hour crush) levels.     

Plasma antioxidant status and motor features in de novo Chinese Parkinson's disease patients

Purpose: This study aimed to explore plasma antioxidant status in de novo Chinese Parkinson's disease (PD) patients and investigate its relationship with specific motor features of PD. Patients and methods: Sixty-four de novo Chinese PD patients and 40 age- and sex-matched healthy controls were recruited. Each motor feature of PD patients was assessed by unified Parkinson's disease rating scale. Plasma antioxidant status, including plasma level of glutathione (GSH) and plasma activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), was detected using enzyme-linked immunosorbent assay. The relationship between the plasma antioxidant status and motor features of PD was evaluated by Spearman's coefficient. Results: Plasma GSH level and plasma activities of GSH-Px, CAT and SOD of PD patients were lower than those of healthy controls. Moreover, the declining activity of plasma CAT was related with the increasing mean postural instability and gait disorder (PIGD) score and growing age. In contrast, the severity of tremor was positively correlated with plasma SOD activity. Conclusion: Our study demonstrates that the plasma antioxidant status is impaired in de novo Chinese PD patients. The complex relationship between the plasma antioxidant status and different motor features indicates that the antioxidant mechanisms underlying tremor and PIGD of PD may be different.     

Neural regulation of glucose 6-phosphate dehydrogenase in rat muscle: effect of denervation and reinnervation

We tested the hypothesis that glucose 6-phosphate dehydrogenase (G6PD) in rat extensor digitorum longus (EDL) muscle is under neural control by studying changes in G6PD activity in EDL muscles following nerve crush-induced denervation and reinnervation. Changes in G6PD were correlated with choline acetyltransferase activity, as well as with neurological function, muscle weights, and muscle isometric twitch tension. The data show a dramatic increase in G6PD following denervation. The gradual recovery of enzyme activity toward normal levels correlates with the return of functional synaptogenesis manifested by the return of neurological function, choline acetyltransferase, and muscle twitch tension. We conclude, therefore, that muscle G6PD is under neural control. G6PD activity provides a facile biochemical indicator of muscle reinnervation.     

Naringenin neutralises oxidative stress and nerve growth factor discrepancy in experimental diabetic neuropathy

Abstract

Objectives:

Present study aims to investigate the ameliorative effects of naringenin (NG) on experimentally induced diabetic neuropathy (DN) in rats.

Methods:

Diabetes was induced by single intraperitoneal injection of streptozotocin (STZ, 60?mg/kg). Naringenin (25 and 50?mg/kg/day) treatment was started 2?weeks after the diabetes induction and continued for five consecutive weeks. Pain threshold behaviour tests were performed at the end of the treatment. Serum levels of glucose, insulin and pro-inflammatory cytokines were assessed. In sciatic tissues, markers oxidative stress, cytokines and neurotrophic factors were measured.

Results:

NG treatments showed significant decrease in paw-withdrawal (P?<?0.01) and tail-flick latency (P?<?0.01). The drug attenuated the diabetic-induced changes in serum glucose, insulin and pro-inflammatory cytokines including tumour necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6). In sciatic nerve, the diabetic-induced alterations in interleukins and oxidative stress biomarkers were significantly attenuated by NG. Decreased sciatic expressions of insulin growth factor (IGF) and nerve growth factor (NGF) in diabetic rats were also ameliorated by NG. Diabetes-induced dysregulated levels of nitric oxide (NO), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) were ameliorated by NG. Histological analysis showed that NG corrected the altered sciatic changes in diabetic animals.

Discussion:

We suggest that neuro-protective effect of NG molecules in sciatic nerve of diabetic rats, through its anti-diabetic as well as antioxidant and anti-inflammatory properties.     

帕金森病血抗氧化酶活性的研究

本文报道６７例帕金森病（ＰＤ）患者血超氧化物歧化酶（ＳＯＤ）．谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ），过氧化氢酶（ＣＡＴ）活性及脂质过氧化物（ＬＰＯ）量的测定结果。ＰＤ病人ＳＯＤ和ＧＳＨ－Ｐｘ活性高于正常对照组，但ＳＯＤ，ＧＳＨ－Ｐｘ和ＣＡＴ的活性及ＬＰＯ量与病程长短无明显关系，也与是否服用美多巴无关。研究结果提示，抗氧化酶活性的改变可能与ＰＤ病因有关。     

Role of oxidative stress in surgical cavernous nerve injury in a rat model

This study investigates the role of oxidative stress in surgical cavernous nerve (CN) injury in a rat model. Eighty‐four male Sprague‐Dawley rats were randomly divided into three groups: group 1, sham‐operated rats; group 2, bilateral CN‐crushed rats; and group 3, bilateral CN‐transection‐and‐sutured‐immediately rats. Oxidative stress was evaluated by malondialdehyde levels, super oxide dismutase (SOD) activities, and glutathione peroxidase (GPX) activities in serum. Erectile function was assessed by CN electrostimulation at 3 months with mean maximal intracavernous pressure (ICP) and maximal ICP per mean arterial pressure. Nerve injury was assessed by toluidine blue staining of CNs and nicotinamide adenine dinucleotide phosphate (NADPH)‐diaphorase staining of penile tissue. GPX protein expression and nitrotyrosine‐3 (NT‐3) levels in penile tissue were measured. Erectile function and the number of myelinated axons of CNs and NADPH‐diaphorase‐positive nerve fibers were statistically decreased between groups, from sham to crush to transection. For markers, both nerve‐injury groups showed increased oxidative stress markers at early time points, with the transection group showing greater oxidative stress than the crushed group and values normalizing to sham levels by week 12. GPX expression and NT‐3 levels in penile tissue were in concordance with the results of SOD and GPX. These results show that oxidative stress plays an important role in injured CNs, and different methods of CN injury can lead to different degrees of oxidative stress in a rat model. © 2015 Wiley Periodicals, Inc.     

Peripheral markers for oxidative stress in Parkinson’s disease patients of Eastern India

Oxidative stress is thought to play a major role in the pathogenesis of Parkinson’s disease (PD). Neurons are highly susceptible to a defective antioxidant scavenging system, thus inducing oxidative changes in human red blood cells (RBCs), in vivo and in vitro. Previous studies on oxidative stress in RBCs in patients with PD have yielded controversial results claiming unaltered activity to reduced activity. We have thus undertaken this study to investigate the possibility of oxidative damage to the RBCs in PD by measuring the cytosolic antioxidant enzymes viz., catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (G-Px). The biochemical parameters were measured in erythrocytes of 80 PD patients and 80 normal age-matched healthy controls. The enzymes activities were correlated with age of patients, age of onset of disease, duration of disease, United Parkinson’s Disease Rating Scale (UPDRS) and Hoehn and Yahr stage. Patients with PD had higher red blood corpuscle (RBC) activity of SOD. The CAT, and G-Px activities were significantly lower in patients with PD compared to the controls. Erythrocyte SOD, CAT and G-Px were markedly lower in those PD patients who were suffering for a greater duration of the disease and in advanced cases of PD. A significant (P < 0.05) negative correlation of enzyme activities with disease duration, UPDRS score and Hoehn and Yahr stage of the disease was found. Results of our present study concludes the implication of oxidative stress as one of the risk factors, which can initiate or promote neurodegeneration in PD by playing a role in dopaminergic neuronal loss and was correlated to the severity of the disease.     

The reduction of superoxide dismutase activity is associated with the severity of neurological soft signs in patients with schizophrenia

This study aimed to explore the relationship between antioxidant enzyme activities and neurological soft signs (NSS) in a sample of patients with schizophrenia. Sixty clinically stable patients with schizophrenia treated mostly by first-generation antipsychotics and 30 matched healthy controls were recruited. NSS were assessed in two groups by a standardized neurological examination (Krebs et al., 2000). The red blood cell (RBC) antioxidant activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were measured by spectrophotometry. RBC activities of all enzymes studied: SOD, GSH-Px and CAT, were significantly lower in the patients compared to control group. All NSS scores were significantly higher in the patients compared to healthy controls' scores. In the patients, a negative correlation was found between RBC SOD activity and NSS total score and motor coordination and motor integration sub-scores. The association between low SOD activity as a marker of oxidative stress and NSS in schizophrenic patients suggests a common pathological process of these abnormalities.     

Progressive motor unit loss in the G93A mouse model of amyotrophic lateral sclerosis is unaffected by gender

We examined whether there are gender differences in the progressive loss of functional motor units in SOD1^G93A transgenic mice. Isometric muscle and motor unit twitch contractions were recorded in fast‐ and slow‐twitch muscles in response to stimulation of the sciatic nerve. Using a modified motor unit number estimation technique (ITS‐MUNE), we found that motor unit numbers declined rapidly from 40 to 90 days of age during the asymptomatic phase of ALS in fast‐ but not slow‐twitch hindlimb muscles of both male and female mice. There was a corresponding decline in twitch and tetanic contractile forces of the fast‐twitch muscles. Gender did not affect the progressive loss of motor units and associated decline in force production. We conclude that gender does not alter progressive, muscle‐specific motor unit loss in ALS, even though gender does influence disease onset. Muscle Nerve 39: 318–327, 2009     

Sprouting of peripherally regenerating primary sensory neurones in the adult central nervous system

We have studied the ability of primary afferent neurones to proliferate within the grey matter of the dorsal horn following the degeneration of other, nearby, afferent fibres. The peripheral branches of primary afferents have the capacity to regenerate successfully over long distances, and we have examined the possibility that when they are so doing, the neurones' status changes to facilitate greatly the sprouting of afferent fibres within the dorsal horn. "Spared root" preparations (rhizotomies of L3, L4, L6, S1, and the caudal half of L5, sparing the rostral half of the L5 dorsal root) were made in adult rats. In some animals (acute preparations) the distribution of the central terminals of the spared root was assessed by labelling the sciatic nerve with WGA-HRP at the time of the rhizotomies. In other animals (chronic preparations), symmetrical bilateral spared roots were made and the sciatic nerve on one side was concomitantly crushed to trigger regrowth of the peripheral branches of these axons. Eight to 10 weeks later the sciatic nerves on both sides were labelled with HRP-WGA. In the acute preparations the reaction product was found in a limited rostrocaudal and mediolateral region of the dorsal horn. In lamina II (the lamina of densest labelling) the labelled terminals occupied an average of 1.17 +/- 0.21 mm2. In chronic preparations, the area of labelled terminals on the side of the uncrushed sciatic nerve was 1.34 +/- 0.28 mm2 (not significantly different from acute animals). However, the labelled area on the side of the crushed sciatic nerve was significantly greater, averaging 2.17 +/- 0.14 mm2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antioxidant enzyme and malondialdehyde levels in patients with panic disorder

There is evidence of an etiopathogenetic role of free radicals (FRs) in some neuropsychiatric disorders. The aim of the present study was to determine whether the activity levels of some antioxidant enzymes [glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT)] and malondialdehyde (MDA), a product of lipid peroxidation, were associated with panic disorder (PD). Twenty patients diagnosed with PD and 20 healthy controls were enrolled in this study. A clinical evaluation and measurements of GSH-Px SOD, CAT and MDA were performed. Additionally, all patients were assessed by the Panic Agoraphobia Scale (PAS). The mean GSH-Px, SOD and MDA levels of the patient group were significantly higher than those of the controls. There was a significant positive correlation between PAS scores and GSH-Px, SOD and MDA levels and between the duration of illness and SOD, CAT and MDA levels in the patient group. In conclusion, our results suggest that FRs may be involved in PD.     

Effect of ischemic preconditioning on antioxidant status in the gerbil hippocampal CA1 region after transient forebrain ischemia

Ischemic preconditioning (IPC) is a condition of sublethal transient global ischemia and exhibits neuro-protective effects against subsequent lethal ischemic insult. We, in this study, examined the neuroprotective effects of IPC and its effects on immunoreactive changes of antioxidant enzymes including superoxide dismutase (SOD) 1 and SOD2, catalase (CAT) and glutathione peroxidase (GPX) in the gerbil hippocampal CA1 region after transient forebrain ischemia. Pyramidal neurons of the stratum pyramidale (SP) in the hippocampal CA1 region of animals died 5 days after lethal transient ischemia without IPC (8.6%(ratio of remanent neurons) of the sham-operated group);however, IPC prevented the pyramidal neurons from subsequent lethal ischemic injury (92.3%(ratio of remanent neurons) of the sham-operated group). SOD1, SOD2, CAT and GPX immunoreactivities in the sham-operated animals were easily detected in pyramidal neurons in the stratum pyramidale (SP) of the hippocampal CA1 region, while all of these immunoreac-tivities were rarely detected in the stratum pyramidale at 5 days after lethal transient ischemia without IPC. Meanwhile, their immunoreactivities in the sham-operated animals with IPC were similar to (SOD1, SOD2 and CAT) or higher (GPX) than those in the sham-operated animals without IPC. Furthermore, their immunoreactivities in the stratum pyramidale of the ischemia-operated animals with IPC were steadily maintained after lethal ischemia/reperfusion. Results of western blot analysis for SOD1, SOD2, CAT and GPX were similar to immunohistochemical data. In conclusion, IPC maintained or increased the expression of antioxidant enzymes in the stratum pyramidale of the hippocampal CA1 region after subsequent lethal transient forebrain ischemia and IPC exhibited neuroprotective effects in the hippocampal CA1 region against transient forebrain ischemia.     

Glycemic control and not protein kinase C inhibition prevents the early decrease of glutathione peroxidase activity in peripheral nerve of diabetic mice

Experimental diabetes promotes changes in biochemical activities of peripheral nervous tissue. Glutathione peroxidase activity decreases in sciatic nerve of diabetic mice very early after onset of experimental diabetes. Effective glycemic control with insulin restores the early lost glutathione peroxidase activity in peripheral nerve of diabetic mice to control values. Data are also presented demonstrating that glutathione peroxidase activity in diabetic mouse peripheral nerve is not modified by the constant delivery of calphostin C, a protein kinase C inhibitor, therefore this decrease seems to be independent on a protein kinase C mediated mechanism. Thus, the early glutathione peroxidase activity decrease in peripheral nerve of diabetic mice is closely related to hyperglycemia, and a tight glycemic control is rather effective in restoring the control levels of this enzymatic activity. The results herein do not rule out the benefits of antioxidant adjuvant therapies in diabetes to help recover the overall decrease in antioxidant defense in peripheral nerve elicited by the decrease of glutathione peroxidase activity.     

Dopamine D2 receptor-mediated antioxidant and neuroprotective effects of ropinirole, a dopamine agonist

Recent information suggests that free radicals are closely involved in the pathogenesis and/or progression of Parkinson's disease (PD). High-dose levodopa therapy has been suggested to increase oxidative stress, thereby accelerating the progression of PD. Based on this viewpoint, free radical scavenging, antioxidant and neuroprotective agents which may prevent the progression of PD have recently attracted considerable attention. For example, ergot derivative dopamine (DA) agonists have been reported to scavenge free radicals in vitro and show a neuroprotective effect in vivo. Non-ergot DA agonists have also recently been used in the treatment of PD despite the lack of substantial evidence for any free radical scavenging activity or antioxidant activity. The present study was conducted to assess the in vitro free radical scavenging and antioxidant activities of ropinirole, a non-ergot DA agonist, as well as its glutathione (GSH), catalase and superoxide dismutase (SOD) activating effects and neuroprotective effect in vivo. Ropinirole scavenges free radicals and suppresses lipid peroxidation in vitro, but these activities are very weak, suggesting that the antioxidant effect of ropinirole observed in vitro may be a minor component of its neuroprotective effect in vivo. Administration of ropinirole for 7 days increased GSH, catalase and SOD activities in the striatum and protected striatal dopaminergic neurons against 6-hydroxydopamine (6-OHDA) in mice. Pre-treatment with sulpiride prevented ropinirole from enhancing striatal GSH, catalase and SOD activities and abolished the protection of dopaminergic neurons against 6-OHDA. Our findings indicate that activation of GSH, catalase and SOD mediated via DA D2 receptors may be the principal mechanism of neuroprotection by ropinirole.