Alterations of antioxidant enzymes and oxidative stress markers in aging

In accordance with the present state of scientific knowledge, the excessive production of free radicals in the organism, and the imbalance between the concentrations of these and the antioxidant defenses may be related to processes such as aging and several diseases. The aging process has been described by various theories. In particular, the free radical theory of aging has received widespread attention which proposes that deleterious actions of free radicals are responsible for the functional deterioration associated with aging. Although, the relationship between lipid peroxidation and aging have been investigated extensively, the studies have produced conflicting results. To investigate the correlation between the oxidative stress and aging, we have determined the levels of lipid peroxidation expressed as thiobarbituric acid reactive substances (TBARS; MDA) and conjugated dien; oxidative protein damage as indicated by carbonyl content and activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in a sample of 100 healthy men and women ranging in age from 20 to 70years. In addition, vitamin E, C levels, reduced glutathione and sulphydryl content were determined. The oxidation end product of nitric oxide (nitrate) was also studied to investigate any role of nitrogen radicals in aging. Our data show that there is an age related increase in lipid peroxidation expressed as MDA and oxidative protein damage as indicated by carbonyl content. Aging is not linked to a decline in antioxidant enzymes except GPx. Our data suggests that the level of oxidative stress increase cannot entirely be attributed to a decrease in the activities of antioxidant defense system and probably various factors may contribute to this process.     

Influence of mulberry (Morus indica L.) leaves on antioxidants and antioxidant enzymes in STZ-diabetic rats

To assess the influence of mulberry (Morus indica L.) leaves on antioxidants and antioxidant enzymes in STZ- diabetic rats as the leaves of mulberry (Morus indica L.) of Moraceae, are reported to be rich in a no. of bioactive principles i.e. antioxidant vitamins, flavonoids and moracins that can fight against oxidative stress in diabetes. STZ-diabetic rats were treated with dried mulberry leaves incorporated in the feed at 25 % level (as per dose response) for 8 weeks in standard experimental conditions in comparison with diabetic glibenclamide–treated and diabetic control rats. At the end of experimental period, fasting blood glucose, serum non-enzymatic antioxidants, hepatic lipid peroxidation and antioxidant enzymes were assayed in all the experimental groups. Hyperglycemia, a 274 % (P?<?0.01) rise in fasting blood glucose and increased oxidative stress as shown by a two fold increase in lipid peroxidation in hepatic tissue, decreased serum non enzymatic antioxidants viz. vit.C (51 %) and E (47 %), significantly decreased activities of hepatic antioxidant enzymes such as glucose-6-phosphate dehydrogenase (43 %), glutathione peroxidase (41 %) and superoxide dismutase (44 %) and significantly increased activity of catalase (39 %) in STZ-diabetic rats were ameliorated by mulberry leaves which is evidenced by significant fall in fasting glucose, and lipid peroxidation, rise in antioxidants as well as the activities of defense enzymes and decrease in the activity of catalase while the antidiabetic drug, glibenclamide showed lesser effects than mulberry leaves. Mulberry leaves protected STZ-diabetic rats against oxidative stress by improving antioxidants and the activities of defense enzymes and controlling hyperglycemia and lipid peroxidation in a better way than the drug.     

Melatonin administration differentially affects age-induced alterations in daily rhythms of lipid peroxidation and antioxidant enzymes in male rat liver

A central clock/pacemaker, suprachiasmatic nuclei of the hypothalamus coordinates and entrains circadian oscillations in the peripheral tissues such as the liver, kidney, heart, lungs etc. called peripheral clocks. These also have endogenous circadian oscillations. The circadian rhythms of antioxidants present in cytosol signify redox state of the cell during day/night cycle. The liver has a major impact on homeostasis through its control on serum protein composition and plays a pivotal role in the metabolism of nutrients, drugs, hormones, and metabolic waste products and undergoes substantial changes in structure and function upon aging. In present study, the temporal patterns of oxidative stress indicators in liver were studied. Daily rhythms of lipid peroxidation end products, reduced glutathione (GSH), oxidized glutathione (GSSG) and antioxidant enzymes such as glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) were studied in liver at variable time points (Zeitgeber Time (ZT) 0, 6, 12 and 18) in three age groups: 3 (adult), 12 and 24?months old male Wistar rats. There was increase in oxidative stress in 12 and 24?months old rats indicated through a significant increase in lipid peroxidation, decrease in GSH/GSSG ratio and antioxidant enzyme activities. In 3?months old rats, lipid peroxidation was maximum at ZT-12 whereas GSH, SOD and CAT activities were minimum at ZT-12. The maximum level in 24?h i.e., acrophases of lipid peroxidation, GPx, SOD and CAT activities in liver cell free extracts altered upon aging. As melatonin, messenger of darkness, an endogenous synchronizer of rhythm, an antioxidant and an antiaging drug, declines with aging we studied the effects of melatonin on activities of these antioxidant enzymes in aging rats. Melatonin administration resulted in differential restoration of acrophases, amplitude, mean as well as daily rhythms of lipid peroxidation and antioxidants in liver of 12 and 24?months old rats.     

Low doses of insulin-like growth factor I improve insulin resistance, lipid metabolism, and oxidative damage in aging rats

GH and IGF-I concentrations decline with age. Age-related changes appear to be linked to decreases in the anabolic hormones, GH and IGF-I. The aim of this study was to investigate the antioxidant, anabolic, and metabolic effects of the IGF-I replacement therapy, at low doses, in aging rats. Three experimental groups were included in this protocol: young healthy controls (17 wk old); untreated old (O) rats (103 wk old); and aging rats (103 wk old) treated with IGF-I during 1 month (2.25 microg IGF-I/100 g body weight(-1).d(-1)). Compared with young controls, untreated aging rats showed a reduction of IGF-I and testosterone levels, and a decrease of serum total antioxidant status, which were corrected by IGF-I therapy. In addition, untreated O presented increased levels of serum glucose with hyperinsulinemia, cholesterol, and triglycerides, and a reduction of free fatty acid concentrations. IGF-I therapy was able to revert insulin resistance, and to reduce cholesterol and triglycerides levels increasing significantly free fatty acid concentrations. The O group showed higher oxidative damage in brain and liver tissues associated with alterations in antioxidant enzyme activities. IGF-I therapy reduced oxidative damage in brain and liver, normalizing antioxidant enzyme activities and mitochondrial dysfunction. In conclusion, low doses of IGF-I restore circulating IGF-I, improve glucose and lipid metabolism, increase testosterone levels and serum total antioxidant capability, and reduce oxidative damage in brain and liver associated with a normalization of antioxidant enzyme activities and mitochondrial function.     

Oxidative stress in the brain of reproductive male rats during aging

Reproduction alters the male physiology. We performed a comprehensive study to examine oxidative stress in the brains of male rats with (experienced) or without (naïve) reproductive activity during aging. Oxidative stress was assessed by measuring the activity of catalase, glutathione peroxidase, superoxide dismutase, glutathione S-transferase, aconitase, and aconitase reactivated, and by measuring lipid peroxidation, protein carbonylation, nitrite and nitrate levels, vitamin C levels, and glutathione (total, reduced, oxidized forms) levels in brain tissue, as well as testosterone and estradiol levels in serum. Reproductively active animals exhibited increased testosterone levels and aconitase activity, suggesting an increased metabolism. Increased antioxidant enzyme activities and increased levels of antioxidant compounds were observed, yet damage to biomolecules was also observed in experienced rats. During aging changes in oxidative stress were observed. We found higher activities of antioxidant enzymes, higher amounts of antioxidants, and more damage at six months of age among experienced animals than among naïve animals. Similar antioxidant activities and levels, and damage were found between the groups at twenty-four months of age. These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.     

Differential response to lipid peroxidation in male and female mice with age: correlation of antioxidant enzymes matters

The aim of this study was to correlate the activity of superoxide dismutase, catalase and glutathion peroxidase in liver and brain of 1, 4 and 18 months old CBA mice of both sexes. In liver, decreased superoxide dismutase and increased glutathione peroxidase activities were observed during aging in male mice. In brain, the increase of catalase and glutathion peroxidase activity during aging was observed only in female mice. Regardless of tissue examined, different sex-related correlation pattern of antioxidant enzyme activity was demonstrated in young and old mice. The cooperation between antioxidant enzymes becomes more coherent with increased lipid peroxidation concentration in liver and brain of older female mice. On the contrary, in older male mice the link among three antioxidant enzymes becomes weaker, regardless of lipid peroxidation concentration which increased in liver and decreased in brain during aging. In older mice lower partial coefficient of correlation than pair correlation demonstrates the influence of the third party in the cooperation of two antioxidant enzymes. The results imply stronger correlative links in old female than male mice, which might explain why old females are better protected from oxidative stress than males.     

Late-onset dietary restriction compensates for age-related increase in oxidative stress and alterations of HSP 70 and synapsin1 protein levels in male Wistar rats

Numerous reports implicate increased oxidative stress in the functional and structural changes occurring in the brain and other organs as a part of the normal aging process. Dietary restriction (DR) has long been shown to be life-prolonging intervention in several species. This study was aimed to assess the potential efficacy of late-onset short term DR when initiated in 21 months old male wistar rats for 3 months on the antioxidant defense system and lipid peroxidation, cellular stress response protein HSP 70 and synaptic marker protein synapsin 1 in discrete brain regions such as cortex, hypothalamus, and hippocampus as well as liver, kidney and heart from 24 month old rats. Age-associated decline in activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione, and elevated levels of lipid peroxidation was observed in brain and peripheral organ as well as increased expression of HSP 70 and reduction in synapsin 1 was observed in brain studied. Late-onset short term DR was effective in partially restoring the antioxidant status and in decreasing lipid peroxidation level as well as enhancing the expression of HSP 70 and synapsin 1 in aged rats. Late onset short term DR also prevented age-related neurodegeneration as revealed by Fluoro-Jade B staining in hippocampus and cortex regions of rat brain. Thus our current results suggest that DR initiated even in old age has the potential to improve age related decline in body functions.     

Differential expressions of antioxidant status in aging rats: the role of transcriptional factor Nrf2 and MAPK signaling pathway

Antioxidant enzymes (AOEs) play an important role in the protection of cells against reactive oxygen species and facilitate the prevention of oxidative stress-induced aging. In the present study, the antioxidant indices, including the content of peroxidation product and the expression of AOEs in rat livers of varying ages (2, 12 and 18-24 months old) were evaluated. Erythrocytes haemolysis induced by free radicals showed significant age-dependent increases (P < 0.05). The content of oxidation products in livers showed that increasing age was associated with serious oxidative injury. The activities of AOEs decreased with increasing age. Expression of the antioxidant and age-related gene, klotho, decreased with increasing age. Western blot assay showed that aged rats experience higher levels of oxidative stress. Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) exhibited an age-dependent decrease. Additionally, the mitogen-activated protein kinase cascade (MAPK) played a regulatory role in signaling transduction. Overall, we suggest that age-related declines of the antioxidant defense are closely involved with the expression of Nrf2 and are regulated by the MAPK family.     

Oxidative stress in the kidney of reproductive male rats during aging

Reproduction alters the male physiology. We performed a comprehensive examination of oxidative stress in the kidneys of male rats with (experienced) or without (naïve) reproductive activity during aging. Oxidative stress was assessed by measuring the activity of catalase, glutathione peroxidase, glutathione S-transferase, and superoxide dismutase, and by measuring protein carbonylation, lipid peroxidation, nitrite and nitrate levels, vitamin C levels, and glutathione (total, reduced, and oxidized forms) levels, and metabolism was accessed by aconitase activity in kidney tissue, as well as testosterone and estradiol levels in serum. Reproductively active animals exhibited increased testosterone levels and altered metabolism. Aging affects tissues and organs and contributes to their functional decline. Elderly naïve rats showed high nitrite and nitrate levels. The experienced rats had less damage in elderly ages, probably because they had higher antioxidant amount and antioxidant enzyme activities at earlier ages, which would have avoided oxidative damage seen in naïve group, and because of the metabolism decline. Glutathione increase in naïve elder rats probably was induced for direct protection against oxidative damage and indirect protection by higher glutathione peroxidase and glutathione S-transferase activities. Linear regression shows that lipid peroxidation levels explained vitamin C levels (B standardized value of 0.42), indicating that vitamin C was properly produced or recruited into kidneys to combat lipid peroxidation. Catalase activity reflected the protein carbonylation and lipid peroxidation levels (B standardized values of 0.28 and 0.48). These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.     

A comprehensive study of myocardial redox homeostasis in naturally and mimetically aged rats

Age-related myocardial dysfunction has important implications with impaired redox homeostasis. Current study focused on investigation of redox homeostasis and histopathological changes in the myocardium of mimetically (MA), naturally aged (NA), and young control (YC) rats. Chronic d-galactose administration to young male Wistar rats (5 months old) was used to set up experimental aging models. We investigated 16 different oxidative damage biomarkers which have evaluated redox homeostasis of cellular macromolecules such as protein, lipid, and DNA. As a protein oxidation biomarker, advanced oxidation end products, protein carbonyl groups, protein-bound advanced glycation end products, dityrosine, kynurenine, and N-formylkynurenine concentrations in MA and NA rats were found to be significantly higher compared to those in YC rats. On the other hand, the levels of protein thiol groups were not significantly different between groups, whereas lipid peroxidation biomarkers such as conjugated diens, lipid hydroperoxides, and malondialdehyde in MA and NA rats were found to be significantly higher in comparison to those in YCs. For the assessment of oxidative DNA damage, we analyzed eight hydroxy-5′-deoxyguanosine concentrations of MA and NA groups which were higher than YCs. As an antioxidant status in the MA and NA groups, Cu–Zn superoxide dismutase, ferric reducing antioxidant power, and total thiol levels were lower than those in the YCs. Only nonprotein thiol levels were not significantly different. We also observed similar histopathological changes in MA and NA rats. We concluded that the mimetic aging model could be considered as a reliable experimental model for myocardial senescence.     

Protective effect of an extract of the oyster mushroom, Pleurotus ostreatus, on antioxidants of major organs of aged rats

This study was undertaken to investigate the putative antioxidant activity of the oyster mushroom, Pleurotus ostreatus, on lipid peroxidation and antioxidant status of major organs of aged (24 month old) rats when compared to young (4 month old) rats. Elevated levels of malondialdehyde (MDA) and significantly lowered levels of reduced glutathione (GSH) and of vitamins C and E were observed in the liver, kidneys, heart and brain of aged rats, when compared to values in young rats. Quantitative analysis of the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) revealed significantly lower values in the liver, kidneys, heart and brain of aged rats. An analysis of isozyme pattern of these enzymes in aged rats also revealed variations in relative concentration, presumably due to oxidative stress. Administration of the extract of P. ostreatus to aged rats resulted in elevated levels of reduced glutathione and vitamins C and E and in increased activities of CAT, SOD and Gpx so that the values in most of these parameters did not differ significantly from those in young rats. In addition, the level of MDA was lowered on administration of mushroom extract to aged rats. These results suggest that treatment with an extract of P. ostreatus can improve the antioxidant status during ageing, therein minimizing the occurrence of age-associated disorders associated with involvement of free radicals.     

Age-related learning and memory deficits in rats: role of altered brain neurotransmitters,acetylcholinesterase activity and changes in antioxidant defense system

Oxidative stress from generation of increased reactive oxygen species or free radicals of oxygen has been reported to play an important role in the aging. To investigate the relationship between the oxidative stress and memory decline during aging, we have determined the level of lipid peroxidation, activities of antioxidant enzymes, and activity of acetylcholine esterase (AChE) in brain and plasma as well as biogenic amine levels in brain from Albino–Wistar rats at age of 4 and 24 months. The results showed that the level of lipid peroxidation in the brain and plasma was significantly higher in older than that in the young rats. The activities of antioxidant enzymes displayed an age-dependent decline in both brain and plasma. Glutathione peroxidase and catalase activities were found to be significantly decreased in brain and plasma of aged rats. Superoxide dismutase (SOD) was also significantly decreased in plasma of aged rats; however, a decreased tendency (non-significant) of SOD in brain was also observed. AChE activity in brain and plasma was significantly decreased in aged rats. Learning and memory of rats in the present study was assessed by Morris Water Maze (MWM) and Elevated plus Maze (EPM) test. Short-term memory and long-term memory was impaired significantly in older rats, which was evident by a significant increase in the latency time in MWM and increase in transfer latency in EPM. Moreover, a marked decrease in biogenic amines (NA, DA, and 5-HT) was also found in the brain of aged rats. In conclusion, our data suggest that increased oxidative stress, decline of antioxidant enzyme activities, altered AChE activity, and decreased biogenic amines level in the brain of aged rats may potentially be involved in diminished memory function.     

Oxidative stress in the kidney of reproductive female rats during aging

Reproduction is a costly life process, and the reproductive investment by females appears to be greater than males in many species. We have analyzed the effects of reproductive investment during aging with respect to oxidative stress parameters in female Wistar rats. We measured the activity glutathione peroxidase, glutathione S-transferase, superoxide dismutase, consumption of hydrogen peroxide, protein carbonylation, lipid peroxidation, nitrite and nitrate levels, and Vitamin C (Vit. C) and E levels. We traced oxidative profiles at ages 3, 6, 12, and 24 months. Animals were grouped according to reproductive experience: experienced or naive with respect to reproductive activity. We measured aconitase activity and sex hormone levels. The naive animals exhibited an increase with respect to experienced in most parameters studied at 6 and 24 months, whereas experienced animals exhibited a similar increase at 3 and 12 months. At 6 months of age, during the period that would represent peak reproductive activity, naive animals showed higher levels of MDA, Vit. C, consumption of hydrogen peroxide and GPx, aconitase, and SOD activities. In naive elderly rats, we observed an increase in oxidative damage markers and an increase in enzymatic and non-enzymatic antioxidants, with the exception of consumption of hydrogen peroxide and Vit. C. In the long term, the reproductive investment was not sufficient to interfere with antioxidant capacity, and did not contribute to oxidative damage in kidneys of female Wistar rats.     

Experimental model of liver oxidative damage induction in rats by halothane

BACKGROUND: The anesthetic halothane can be reductively metabolized to reactives intermediates that may initiate lipid peroxidation accompanied by hepatic injury. Hypoxia and phenobarbital pretreatment in rats increases metabolism of halothane, the oxidative stress, cause liver antioxidant enzymes changes and tissue damage. AIMS: We investigated the effect of halothane on hepatic lipid peroxidation and on hepatic histology after increases reductive metabolism of halothane caused by hypoxia and phenobarbital pretreatment. METHODS: Twenty-five male wistar rats were divided in five equals groups: CO (Control), HO14 (Halothane/Hypoxia), F (fenobarbital alone), O14 (Hypoxia alone) and H (Halothane alone). After 24 hours the rats were killed, their livers removed to determine chemoluminescence, thiobarbituric acid-reactive substances, catalase, superoxide dismutase, and blood samples were taken to determine AST and ALT. The histopathologic evaluation was performed with hematoxylin and eosin staining. Histopathologic scores are presented as 25th-75th percentile/range values and median +/- range. RESULTS/CONCLUSION: Halothane-hypoxic exposure resulted in a significant changes in the activities of antioxidant enzymes, and induced hepatic lipoperoxidation. Moreover it resulted in histopathologic liver injury as well as significant increase of serum activity of AST and ALT.     

Catechin Averts Experimental Diabetes Mellitus-Induced Vascular Endothelial Structural and Functional Abnormalities

Diabetes mellitus is associated with an induction of vascular endothelial dysfunction (VED), an initial event that could lead to the pathogenesis of atherosclerosis and hypertension. Previous studies showed that catechin, a key component of green tea, possesses vascular beneficial effects. We investigated the effect of catechin hydrate in diabetes mellitus-induced experimental vascular endothelial abnormalities (VEA). Streptozotocin (50 mg/kg, i.p., once) administration to rats produced diabetes mellitus, which subsequently induced VEA in 8 weeks by markedly attenuating acetylcholine-induced endothelium-dependent relaxation in the isolated aortic ring preparation, decreasing aortic and serum nitrite/nitrate concentrations and impairing aortic endothelial integrity. These abnormalities in diabetic rats were accompanied with elevated aortic superoxide anion generation and serum lipid peroxidation in addition to hyperglycemia. Catechin hydrate treatment (50 mg/kg/day p.o., 3 weeks) markedly prevented diabetes mellitus-induced VEA and vascular oxidative stress. Intriguingly, in vitro incubation of L-NAME (100 μM), an inhibitor of nitric oxide synthase, or Wortmannin (100 nM), a selective inhibitor of phosphatidylinositol 3-kinase (PI3K), markedly prevented catechin hydrate-induced improvement in acetylcholine-provoked endothelium-dependent relaxation in the diabetic rat aorta. Moreover, catechin hydrate treatment considerably reduced the elevated level of serum glucose in diabetic rats. In conclusion, catechin hydrate treatment prevents diabetes mellitus-induced VED through the activation of endothelial PI3K signal and subsequent activation of eNOS and generation of nitric oxide. In addition, reduction in high glucose, vascular oxidative stress, and lipid peroxidation might additionally contribute to catechin hydrate-associated prevention of diabetic VEA.     

Relation of oxidative protein damage and nitrotyrosine levels in the aging rat brain

An increase in oxidative stress may contribute to the development of oxidative protein damage in the aging rat brain. In the present study, we investigated the relation between nitrotyrosine levels and other oxidative protein damage parameters such as protein carbonyl and protein thiol, as well as oxidative stress parameters such as total thiol, nonprotein thiol, and lipid hydroperoxides in the brain tissue of young, adult, and old Wistar rats. Brain nitrotyrosine levels of old rats were significantly decreased compared with those of young rats. Young and adult rats were not significantly different as far as these parameters were concerned, however, brain protein carbonyl and lipid hydroperoxide levels of old rats were significantly increased compared with those of young and adult rats. On the other hand, brain tissue total thiol, nonprotein thiol, and protein thiol levels of old rats were significantly decreased compared with those of young and adult rats. The strong correlation we found between protein carbonyl and lipid hydroperoxide levels indicates a striking relation between protein oxidation and lipid peroxidation in the aging brain tissue. The results of this study suggest that protein carbonyl formation is both a sensitive and a specific marker of brain aging. However, decreased nitrotyrosine levels in old rats, in contradiction to the expected, may be due to mechanisms other than oxidative protein damage in the aging rat brain.     

Effect of aging on enzymatic antioxidant defenses in rat liver mitochondria.

Antioxidant defenses within liver mitochondria are pivotal in preventing liver damage from oxidative toxicants. In this study we determined the activities of glutathione peroxidase (GPO), superoxide dismutase (SOD) and glutathione reductase (GRD) in mitochondria from livers of variously aged Fischer 344 rats. A mixed pattern of age-associated alterations in mitochondrial antioxidant activities was observed. In male rats, GRD activity decreased in old age, whereas GPO and SOD activities increased. In female rats, GPO activity decreased with age, but SOD activity increased and GRD activity was unchanged. Age-associated decreases in antioxidant protection from mitochondrial enzymes appeared to be counterbalanced by increases in protection from other enzymes.     

Oxidative stress decreases in the trophocytes and fat cells of worker honeybees during aging

Trophocytes and fat cells of honeybees have been used for cellular senescence studies, but their oxidative stress and antioxidant enzyme activities with aging in workers is unknown. Here, we assayed reactive oxygen species and the activities of antioxidant enzymes in the trophocytes and fat cells of young and old workers. Young workers had higher reactive oxygen species levels, higher superoxide dismutase and thioredoxin reductase activities as well as lower catalase and glutathione peroxidase activities compared to old workers. Adding these results up, we propose that oxidative stress decreases with aging in the trophocytes and fat cells of workers.     

Serum biochemical responses under oxidative stress of aspartame in wistar albino rats

ObjectiveTo study whether the oral administration of aspartame (40 mg/kg body weight) for 15 d, 30 d and 90 d have any effect on marker enzymes, some selective liver and kidney function parameter, lipid peroxidation and antioxidant status in serum. To mimic human methanol metabolism, folate deficient animals were used.MethodAnimal weight, complete hemogram, marker enzyme in serum, some selected serum profile reflect liver and kidney function, plasma corticosterone level, and in serum, lipid peroxidation, nitric oxide, enzymatic and non-enzymatic antioxidant level was measured .ResultAfter 15 d of aspartame administration animals showed a significant change in marker enzymes, and antioxidant level. However, after repeated long term administration (30 d and 90 d) showed a significant change in some selected serum profile reflects liver and kidney function, along with marker enzymes, and antioxidant level.ConclusionsThis study concludes that oral administration of aspartame (40 mg/kg body weight) causes oxidative stress in Wistar albino rats by altering their oxidant/antioxidant balance.     

The in vivo antioxidant effectiveness of alpha-tocopherol in oxidative stress induced by sodium nitroprusside in rat red blood cells

Reactive oxygen species avidly reacts with nitric oxide (NO) producing cytotoxic reactive nitrogen species capable of nitrating proteins and damaging other molecules which leads to the reduction of erythrocyte deformability. The aim of this investigation was to assess the importance of alpha-tocopherol (Vit-E) in the total antioxidant status of the erythrocytes in sodium nitroprusside (SNP), a nitric oxide donor, induced oxidative stress and its relation to erythrocyte deformability. Male Swiss Albino rats were used in 4 groups, comprising of 10 animals in each group. The first group was the control, and the other groups were administered SNP (10 mg/kg, i.p.), Vit-E (10 mg/kg, i.p.) + SNP, and SNP + L-NAME (10 mg/kg, i.p.), respectively. Relative filtration rate (RFR), relative filtration time (RFT) and relative resistance (Rrel) were determined as the indexes of erythrocyte deformability. In addition, malondialdehyde (MDA, as an index of lipid peroxidation) and nitric oxide levels and the antioxidant activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) were also determined in the red blood cells of all groups revealing the oxidant-antioxidant activity. RFT and the Rrel of the erythrocytes of the SNP-treated rats increased significantly (p<0.05) whereas the RFR of the erythrocytes decreased (p<0.05) in comparison to all groups reflecting the impaired deformability. This reduction in RFR was prevented with both L-NAME or Vit-E incubation. Vit-E has also reduced the Rrel of the erythrocyte which reveals that it has improved the erythrocyte deformability. Lipid peroxidation was suppressed by Vit-E and L-NAME significantly, where the red blood cell deformability was improved. Furthermore, SOD and CAT activities were significantly stimulated with SNP treatment (p<0.05), where as GSH-Px remained unchanged. In the contrary, GSH-Px activity was triggered significantly by Vit-E administration, whereas the SOD and CAT activities were reduced (p<0.05). As a result, these data reveal that Vit-E improves the erythrocyte deformability in SNP-induced oxidative stress by its antioxidant effects on the lipid peroxidation and antioxidant enzyme activities.