High fat diet increases the incidence of orofacial dyskinesia and oxidative stress in specific brain regions of rats

Haloperidol-induced orofacial dyskinesia (OD) is a putative animal model of tardive dyskinesia (TD) whose pathophysiology has been related to free radical generation and oxidative stress. Schizophrenic patients have been reported to eat a diet higher in fat than the general population and dietary fat intake can lead to an increase in oxidative stress in animal models. The objective of this study was to determine whether association of ingestion of a high fat diet with prolonged haloperidol treatment could lead to OD and oxidative stress in the rat brain. Haloperidol decanoate administration (38 mg/kg, IM, which is equivalent to 1 mg/kg/day) monthly for a period of 6 months to rats fed previously with a high fat and normo fat diets (6 months) caused a increase in vacuous chewing (VCM) and duration of facial twitching (FT). Haloperidol caused a reduction in body weight gain and the loss of body weight occurred after 4 months of treatment with haloperidol. The effects on body weight were more accentuated in HF diet group. HF diet ingestion was associated with an increase in TBARS levels in cerebellum and cerebral cortex (regardless of haloperidol treatment). A significant dietxhaloperidol treatment interaction in striatum, subcortical parts and the region containing the substantia nigra was observed for TBARS. In fact, haloperidol caused an increase in TBARS levels of these regions only in rats fed with the HF. These results indicate that a high fat diet caused a transitory increase in haloperidol-induced OD in rats and this in part can be related to the haloperidol-induced oxidative stress in brain structures involved with OD.     

Protective effects of fruit extracts of Hippophae rhamnoides L. against arsenic toxicity in Swiss albino mice

Seabuckthorn (Hippophae rhamnoides L.) berry has a long history of applications as a food and medicinal ingredient in eastern countries. The present study was carried out to investigate the effect of different fruit extracts of H. rhamnoides on altered biochemical parameters indicative of haematological alterations, tissue oxidative stress, and arsenic concentration in arsenic-exposed mice (2.5 mg/kg body weight, intraperitoneally). Two aqueous extracts (at room temperature and under reflux condition) and an ethanolic extract of H. rhamnoides at a dose of 500 mg/kg body weight were co-administered daily during arsenic exposure in mice for 3 weeks. Exposure to arsenic led to a significant inhibition of blood delta-aminolevulinic acid dehydratase (ALAD) activity, suggesting disturbed haem synthesis pathway. Arsenic also caused significant depletion of reduced hepatic glutathione (GSH) level, glutathione S-transferase (GST) and glutathione peroxidase and catalase activities, while it increased the level of thiobarbituric acid reactive substance (TBARS), suggesting liver oxidative stress. Most of the altered biochemical variables responded favorably to the co-supplementation of H. rhamnoides, particularly the aqueous fruit extract, extracted at room temperature (HF-WRT). However, arsenic concentration in blood and tissues remained unchanged, suggesting the lack of chelating property of fruit extract of H. rhamnoides. The present study, thus, led us to conclude that the fruit extract of H. rhamnoides has a significant protective role against arsenic-induced oxidative injury. However, it lacks the ability to remove arsenic from the binding sites, suggesting that the herbal extract could be co-administered with a chelating agent of known efficacy during treatment of arsenic to achieve the optimum effect of chelation treatment.     

Chronic subhepatotoxic exposure to arsenic enhances hepatic injury caused by high fat diet in mice

Arsenic is a ubiquitous contaminant in drinking water. Whereas arsenic can be directly hepatotoxic, the concentrations/doses required are generally higher than present in the US water supply. However, physiological/biochemical changes that are alone pathologically inert can enhance the hepatotoxic response to a subsequent stimulus. Such a ‘2-hit’ paradigm is best exemplified in chronic fatty liver diseases. Here, the hypothesis that low arsenic exposure sensitizes liver to hepatotoxicity in a mouse model of non-alcoholic fatty liver disease was tested. Accordingly, male C57Bl/6J mice were exposed to low fat diet (LFD; 13% calories as fat) or high fat diet (HFD; 42% calories as fat) and tap water or arsenic (4.9 ppm as sodium arsenite) for ten weeks. Biochemical and histologic indices of liver damage were determined. High fat diet (± arsenic) significantly increased body weight gain in mice compared with low-fat controls. HFD significantly increased liver to body weight ratios; this variable was unaffected by arsenic exposure. HFD caused steatohepatitis, as indicated by histological assessment and by increases in plasma ALT and AST. Although arsenic exposure had no effect on indices of liver damage in LFD-fed animals, it significantly increased the liver damage caused by HFD. This effect of arsenic correlated with enhanced inflammation and fibrin extracellular matrix (ECM) deposition. These data indicate that subhepatotoxic arsenic exposure enhances the toxicity of HFD. These results also suggest that arsenic exposure might be a risk factor for the development of fatty liver disease in human populations.     

Hypoglycemic and antioxidative effects of hydroxyethyl methylcellulose in mice fed with high fat diet

The effect of hydroxyethyl methylcellulose (HEMC) with different viscosities on the glucose metabolism and antioxidative defense system in high fat-fed mice was investigated. The mice were randomly divided into five dietary groups: normal control diet (NC), high fat diet (HF), and high fat diet supplemented with high viscosity (HF-HV), moderate viscosity (HF-MV), and low viscosity (HF-LV) HEMC fibers. After 6 weeks, the HF group showed a marked increase in body weight gain, body fat, blood glucose concentration, insulin level, and erythrocyte lipid peroxidation rate relative to the NC group. However, supplementation of HEMC in the diet suppressed these high fat-induced hyperglycemia and oxidative stress through enhancement of the activities of hepatic glucokinase and antioxidant enzymes. The hypoglycemic and antioxidative effects increased with increased viscosity of the HEMC consumed. These results illustrate that HEMC with high viscosity may be useful in the management of high fat diet-induced hyperglycemia and oxidative stress.     

Effect of exogenous leptin administration on high fat diet induced oxidative stress

The objective of the present study was to explore the tissue lipid peroxidation and antioxidant status in mice receiving exogenous leptin along with high fat diet for a period of 6 weeks. Significantly elevated levels of tissue thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and significantly lowered levels of glutathione and its related enzymes were observed in the liver, heart and kidney of mice fed with a high fat diet as compared with the control mice fed with a standard pellet diet. Subsequent to the treatment with high fat diet (ie., after the initial period of 30 days) exogenous leptin (230 microg kg(-1) body weight) was simultaneously administered along with the regular high fat diet every alternate day for 15 days. Leptin administration significantly lowered the tissue levels of TBARS, CD and elevated the activities of reduced glutathione (GSH), glutathione peroxidase (GPx) and glutathione S-transferase (GST) in both the control and high fat diet fed mice. Thus leptin supplementation was found to be effective in attenuating high fat diet induced oxidative stress.     

Investigation into the influence of a high fat diet on antipsychotic-induced weight gain in female rats

Atypical antipsychotic drug therapy may result in substantial weight gain, increased adiposity and the promotion of metabolic abnormalities. The mechanism(s) which underlie such effects remain unclear. Previous studies in our laboratory have demonstrated significant weight gain in female rats maintained on a standard laboratory diet after sub-chronic administration of olanzapine and risperidone, but not ziprasidone. The aim of this paper is to investigate the effect of antipsychotic drugs on body weight, ingestive behaviour and adiposity in female rats with access to a high fat diet. Adult female rats given free access to a high fat diet received either olanzapine (2 mg/kg), risperidone (0.5 mg/kg), ziprasidone (2.5 mg/kg) or vehicle for 28 days. Body weight, food and water intake in addition to intra-abdominal fat deposition were assessed. Olanzapine initially increased body weight but by the end of the study olanzapine animals appeared to have lost weight compared to the vehicle-treated group. Olanzapine-induced reductions in body weight were accompanied by a significant hypophagia during weeks 3 and 4. Risperidone increased body weight during week 1 only and reduced intake of a high fat diet during weeks 3 and 4. Ziprasidone was without effect on indices of body weight and ingestive behaviour. There were no effects of antipsychotic drugs on intra-abdominal fat deposition. Access to a diet high in fat attenuated weight gain induced by olanzapine and risperidone in female rats.     

机械加载对高脂饮食诱导的肥胖和非酒精性脂肪肝的治疗作用

目的 探讨机械加载对高脂饮食诱导的肥胖和非酒精性脂肪肝的疗效。方法 选用6周龄的C57BL/6雌性小鼠30只,体质量约18 g,按随机数字表法分为正常对照组（NC组）、高脂饮食组（HF组）和高脂饮食机械加载治疗组（HF+L组）,每组10只,持续饮食诱导12周。高脂饮食6周后,HF+L组进行机械加载治疗6周。实验动物进行体成分分析,观测全身体脂含量的变化。收集肾周脂肪、子宫周脂肪、肠系膜脂肪、腹股沟脂肪和肝脏并称量湿质量。留取部分肝脏做组织形态学检测,油红O和HE染色分析观察肝脏的病理改变,部分肝脏用于Western blot检测内质网应激相关蛋白（eIF2α、p-eIF2α、ATF4）的表达。结果 与NC组相比,高脂饮食导致HF组体质量、体脂明显增加,机械加载治疗后,HF+L组体质量、体脂较HF组明显降低（P＜0.05）。肝脏组织学结果表明,高脂饮食导致一定程度的肝脏脂肪变性,通过治疗后,脂肪变性得到有效缓解（P＜0.05）。Western blot分析结果表明,高脂饮食导致小鼠肝脏eIF2α、p-eIF2α和ATF4蛋白表达升高,机械加载能够抑制肝脏p-eIF2α和ATF4蛋白的表达。结论 机械加载能够有效缓解高脂饮食导致的体质量、体脂增加及非酒精性脂肪肝,其治疗作用可能与肝脏内质网应激有关。     

Effects of acarbose on food intake,body weight and fat depots in lean and obese rats

Effects of dietary acarbose at 0, 5, 15 and 50 mg per 100 g diet on food intake and body weight were studied for two months in female rats. The relationships between diet composition, the drug dose and the type of obesity were examined. In lean rats receiving the drug in a high carbohydrate diet (70 Cal.%), mean food intake was similar to control at 5 and 15 mg dietary levels, but was significantly increased at 50 mg. Body weight was significantly reduced only at the 15 mg level. In VMH obese rats receiving the drug in a high carbohydrate diet, it resulted in significant reductions in food intake at the 15 and 50 mg drug levels and in significant reductions in body weight at all three drug levels. In dietary obese rats receiving the drug in a high carbohydrate diet and also in a 32% sucrose drinking solution, food intake and body weight were significantly reduced at each of the drug levels. In dietary obese rats receiving the drug in a high fat diet (70 Cal.%), acarbose at all levels resulted in only small and usually not significant changes in either food intake or body weight. Weight of fat depots were significantly reduced at the 50 mg dietary level in all instances where a high carbohydrate diet was used while at the 5 mg level, fat depots were reduced only in the VMH obese, with the sucrose obese showing a trend for reduced depots. Acarbose in the high fat diet resulted in no significant changes in weight of fat depots. These data indicate that acarbose in a high carbohydrate diet is effective in reducing weight of rats, and that obese usually show a greater reduction in food intake and body weight than lean rats.     

Chronic high fat,high cholesterol supplementation decreases 18 kDa Translocator Protein binding capacity in association with increased oxidative stress in rat liver and aorta

It is well known that high fat and high cholesterol levels present a contributing factor to pathologies including fatty liver and atherosclerosis. Oxidative stress is also considered to play a role in these pathologies. The 18 kDa Translocator Protein (TSPO), formerly known as the peripheral-type benzodiazepine receptor, is known to be involved in cholesterol metabolism, oxidative stress, and cardiovascular pathology. We applied a high fat high cholesterol atherogenic (HFHC) diet to rats to study correlations between cardiovascular and liver pathology, oxidative stress, and TSPO expression in the liver and the cardiovascular system. This study corroborates the presence of increased oxidative stress markers and decreased anti-oxidants in liver and aorta. In addition, it appeared that induction of oxidative stress in the liver and aorta by atherogenic HFHC diet was accompanied by a reduction in TSPO binding density in both these tissues. Our data suggest that involvement of TSPO in oxidative stress and ROS generation, as reported in other studies, may also take part in atherogenesis as induced by HFHC diet. Presently, it is not clear whether this TSPO response is compensatory for the stress induced by HFHC diet or is a participant in the induction of oxidative stress.     

Mechanism of protection of moderately diet restricted rats against doxorubicin-induced acute cardiotoxicity

Clinical use of doxorubicin (Adriamycin), an antitumor agent, is limited by its oxyradical-mediated cardiotoxicity. We tested the hypothesis that moderate diet restriction protects against doxorubicin-induced cardiotoxicity by decreasing oxidative stress and inducing cardioprotective mechanisms. Male Sprague-Dawley rats (250-275 g) were maintained on diet restriction [35% less food than ad libitum]. Cardiotoxicity was estimated by measuring biomarkers of cardiotoxicity, cardiac function, lipid peroxidation, and histopathology. A LD(100) dose of doxorubicin (12 mg/kg, ip) administered on day 43 led to 100% mortality in ad libitum rats between 7 and 13 days due to higher cardiotoxicity and cardiac dysfunction, whereas all the diet restricted rats exhibited normal cardiac function and survived. Toxicokinetic analysis revealed equal accumulation of doxorubicin and doxorubicinol (toxic metabolite) in the ad libitum and diet restricted hearts. Mechanistic studies revealed that diet restricted rats were protected due to (1) lower oxyradical stress from increased cardiac antioxidants leading to downregulation of uncoupling proteins 2 and 3, (2) induction of cardiac peroxisome proliferators activated receptor-alpha and plasma adiponectin increased cardiac fatty acid oxidation (666.9+/-14.0 nmol/min/g heart in ad libitum versus 1035.6+/-32.3 nmol/min/g heart in diet restriction) and mitochondrial AMPalpha2 protein kinase. The changes led to 51% higher cardiac ATP levels (17.7+/-2.1 micromol/g heart in ad libitum versus 26.7+/-1.9 micromol/g heart in diet restriction), higher ATP/ADP ratio, and (3) increased cardiac erythropoietin and decreased suppressor of cytokine signaling 3, which upregulates cardioprotective JAK/STAT3 pathway. These findings collectively show that moderate diet restriction renders resiliency against doxorubicin cardiotoxicity by lowering oxidative stress, enhancing ATP synthesis, and inducing the JAK/STAT3 pathway.     

Long-term exposure to crotonaldehyde causes heart and kidney dysfunction through induction of inflammatory and oxidative damage in male Wistar rats

Crotonaldehyde is a ubiquitous hazardous pollutant, present in cigarette smoke and automobile exhaust and is endogenously generated by lipid peroxidation. Most of the current studies focus on its lung toxicity. However, there have been few investigations on the cardiac and renal toxicity caused by crotonaldehyde exposure. We hypothesized that oral intake of crotonaldehyde can cause inflammatory and oxidative/nitrosative damage to the heart and kidneys. Therefore, we treated male rats with crotonaldehyde by gavage at 0, 2.5, 4.5, and 8.5?mg/kg/day for 120?d and evaluated the alterations in histological and serological parameters, oxidative state, and inflammation responses to explore the roles of crotonaldehyde-induced oxidative/nitrosative stress and inflammation in the heart and kidney dysfunction and to explore the relationship between heart and kidney dysfunction. We found that body weight increment, as well as heart and kidney coefficients decreased with an increasing crotonaldehyde dosage. Histological examinations indicated that crotonaldehyde exposure led to focal myocardial necrosis, cardiac fibrosis, renal tubular epithelial cell edema, and renal lymphocyte infiltration. We also assessed the impact of crotonaldehyde treatment on oxidative/nitrosative stress markers, antioxidant enzymes, inflammatory biomarkers, heart/kidney functional markers, and angiotensin II-aldosterone-brain natriuretic peptide (AngII-ALD-BNP) levels. Overall, we found that proinflammatory cytokine and malondialdehyde levels increased in a dose-dependent manner. Furthermore, crotonaldehyde treatment (4.5 and 8.5?mg/kg) significantly prevented the upregulation of antioxidant enzyme activity, thereby increasing oxidative/nitrosative stress (p?相似文献   

Changes in tissue oxidative stress,brain biogenic amines and acetylcholinesterase following co-exposure to lead,arsenic and mercury in rats

The present study investigated the toxic effects of individual, combined (binary and ternary) exposure to lead, arsenic and mercury on, (i) oxidative stress (ii) alterations in brain biogenic amines and (iii) tissue metals concentration. Rats were exposed to lead, arsenic and mercury either individually (30 ppm in drinking water), various binary (15 ppm each) or ternary combination (10 ppm each) for a period of 6 months. Lead + arsenic and lead + arsenic + mercury co-exposure led to a significant increase in the blood oxidative stress. Mercury + arsenic and lead + arsenic + mercury co-exposure produced a more pronounced hepatotoxicity while, lead + arsenic and lead + arsenic + mercury produced a significant increase in hepatic oxidative stress. Kidney oxidative stress and changes in brain biogenic amines were more prominent in animals exposed to three metals. Accumulation of three metals did not exhibit the pattern as in the case of oxidative stress. Exposure to two toxic metals also showed less accumulation of toxic metals suggesting possible antagonism. The present study thus provides some interesting observations on the interaction between lead, arsenic and mercury. Co-exposure to lead + arsenic + mercury led to a more pronounced increase in oxidative stress in liver and kidneys compared to other exposed groups.     

Effect of naloxone on the long-term body weight gain induced by repeated postnatal stress in male mice

Stress during the early postnatal life of laboratory animals can induce body weight gain in adulthood. Exposure of mice to repeated postnatal stress has been shown to increase body weight some weeks after the recording of a hyposensitivity to thermal nociceptive stimulation. Since the increase in nociceptive threshold after repeated environmental manipulations can be interpreted as a behavioral index of stress-induced endogenous opioid release, the present experiment was designed to study whether the stress-induced body weight gain could be prevented by a chronic treatment with the opioid antagonist naloxone. Sixteen litters of CD-1 male mice were used. Treatments took place from day 2 to day 19 of postnatal life. As well as body weight we measured spontaneous motor activity and food and water consumption. Body length and epididymal fat pad weight were also measured, at the end of the experiment. Stress (i.e. a daily saline injection schedule) increased the rate of body weight gain and the epididymal fat pad weight; a daily injection schedule of naloxone did not induce these effects. No significant differences were evident among groups regarding body length, motor activity, or food and water intake. The data suggest that repeated postnatal saline injections may induce long-term modifications in body and epididymal fat weights and that these effects may be mediated by endogenous opioids.     

Effects of prolonged propranolol treatment on left ventricular remodeling and oxidative stress after myocardial infarction in rats

Mechanisms determining the benefit of beta blockade in patients with heart failure remain incompletely understood but are assumed consequent to prevention of deleterious effects of catecholamines. Recent studies have demonstrated that oxidative stress in congestive heart failure may be related to increased catecholamine levels. The aim of this study was to examine effects of long-term treatment with propranolol on progression of left ventricular (LV) dysfunction, remodeling and oxidative stress on an experimental model of chronic heart failure. Six weeks after myocardial infarction by coronary ligation, Wistar rats were randomized to two groups: 10 weeks of therapy with propranolol (50 mg/kg/day in drinking water) and no treatment (infarcted controls). A third group was sham-operated rats without treatment. Animals were anesthetized for hemodynamic measurements, and hearts were then removed for histologic analysis, papillary muscle contractility study, and oxidative stress measurements using thiobarbituric acid reactive substance (TBARS) determination. Control infarcted rats demonstrated significant alterations of hemodynamic parameters and remodeling with increase of heart weight/body weight, of right ventricular lateral wall thickness, of LV circumference, LV septal area/body weight, and LV papillary muscle weight/body weight as compared with sham. In propranolol-treated rats, hypertrophy of the LV septum, papillary muscle, and right ventricle were similar to those of the infarcted control. Myocardial oxidative stress was significantly increased in control infarcted rats compared with sham, and propranolol prevented such oxidative stress increase. Papillary muscle isometric tension parameters were not significantly different among groups. Propranolol treatment prevented isoprenaline-induced spontaneous papillary muscle activity in vitro. Oxidative stress is increased in the rat model of heart failure secondary to coronary ligation. Long-term treatment with propranolol in vivo does not modify the compensatory process of hypertrophy but completely abolishes the oxidative stress increase and reduces the increased cardiac sensitivity to catecholamine-induced arrhythmias observed in this experimental model of heart failure.     

Curcumin Attenuates Oxidative Stress and Activation of Redox-Sensitive Kinases in High Fructose- and High-Fat-Fed Male Wistar Rats

The present study was carried out to investigate the effects of curcumin on oxidative stress and redox-sensitive kinases in high fructose- and high-fat-fed rats. Sixty rats were randomly divided into six groups with ten animals each. Rats were fed with a standard rodent diet, high fructose diet (60%), and high-fat diet (30%). Curcumin was administered to control, high fructose and high fat diet groups for ten weeks. At the end of the study, body weight and blood glucose levels were measured. The antioxidant enzymes GSH (reduced glutathione), GPx (glutathione peroxidase), and catalase activities were estimated in the blood. MDA, TAS, and TOS were estimated in the plasma, liver, and kidney. Curcumin treatment decreased body weight and blood glucose levels in the rats fed with fructose and high-fat diet. Antioxidant enzymes and plasma TAS were significantly improved by curcumin treatment in high fructose-fed rats, whereas in high-fat-fed rats, there was an increase only in the GPx activity. Curcumin significantly attenuated the elevation of plasma MDA and TOS in both diet groups. Hepatic MDA and TOS were found to be decreased upon curcumin supplementation in both diet groups, whereas a decrease in the renal MDA levels was observed only in fructose-treated rats, not in fat-fed rats. Curcumin treatment elevated liver TAS in rats fed only with the fructose-rich diet. Curcumin showed a significant decrease in the oxidative stress index (OSI) in plasma, liver, and kidney tissues in both diet groups. ERK phosphorylation was significantly decreased in both diet groups by curcumin treatment. Similarly, curcumin reduced the phosphorylation of p38 MAPK only in the high fructose-fed rats, not in the high-fat-fed rats. No significant changes were found in JNK phosphorylation in both diet groups. Thus, curcumin may be effective in the management of diet-induced oxidative stress and could be explored as a therapeutic adjuvant against complications associated with obesity and diabetes.     

Protective Effect of Gymnema sylvestre Ethanol Extract on High Fat Diet-induced Obese Diabetic Wistar Rats

Obesity is associated with numerous co-morbidities such as cardiovascular diseases, type 2 diabetes, hypertension and others. Therefore, the present study was planned to investigate the effect of water- soluble fraction of Gymnema sylvestre ethanol extract on biochemical and molecular alterations in obese diabetic rats. Diabetes was induced by single i.v. injection of streptozotocin (45 mg/kg) via tail vein. Obesity was induced by oral feeding of high fat diet for a period of 28 days in diabetic rats. Body weight gain, food intake, water intake, hemodynamic parameters (systolic, diastolic, mean arterial blood pressures and heart rate), serum biochemical parameters (leptin, insulin, lipid levels, apolipoprotein B and glucose), cardiomyocyte apoptosis (cardiac caspase-3, Na⁺/K⁺ ATPase activity and DNA fragmentation) organs and visceral fat pad weight and oxidative stress parameters were measured. Oral treatment with water soluble fraction of Gymnema sylvestre ethanol extracts (120 mg/kg/p.o.) for a period of 21 days, resulted in significant reduction in heart rate, mean arterial pressure, serum leptin, insulin, apolipoprotein B, lipids, glucose, cardiac caspase-3 levels, Na⁺/K⁺ ATPase activity and DNA laddering, visceral fat pad and organ''s weight and improved the antioxidant enzymes levels in the high fat diet induced obesity in diabetic rats. The results of present study reveal that water soluble fraction of Gymnema sylvestre ethanol extract could be useful intervention in the treatment of obesity and type-2 diabetes mellitus.     

Plasma polyphenols and antioxidants, oxidative DNA damage and endothelial function in a diet and wine intervention study in humans.

An intervention study was performed to evaluate the influence of a Mediterranean diet, a high fat diet, and their supplementation with red wine in moderate amounts, on biochemical, physiological, and clinical parameters related to atherosclerosis and other chronic diseases. For 3 months two groups of 21 male volunteers each, received either a Mediterranean diet or a high fat diet; during the second month, red wine was added isocalorically, 240 ml/day. Participants were kept under close medical and nutritional surveillance. At days 0, 30, 60 and 90, clinical, physiological and biochemical evaluations were made. Plasma vitamin C was significantly decreased in the high fat diet group compared to the Mediterranean diet group. After wine supplementation to the Mediterranean diet, a significant 13.5% increase in plasma vitamin C was observed. Furthermore, when wine was added vitamin E decreased significantly in plasma, 15% in the high fat diet and 26% in the Mediterranean diet. Total plasma antioxidant capacity (total antioxidant reactivity) increased 28% above basal levels in the Mediterranean diet group, but not in the high fat diet group. In both groups, wine induced a marked increase in total antioxidant reactivity above basal levels, 56% and 23%, respectively. Oxidative DNA damage, detected as 8-hydroxydeoxyguanosine (8-OHdG) levels in blood leukocyte DNA, was markedly increased by the high fat diet; however, it was strongly reduced, to approximately 50% basal values, after wine supplementation, both in the high fat diet and Mediterranean diet groups. Endothelial function, evaluated noninvasively as flow-mediated vascular reactivity of the brachial artery, was suppressed by the high fat diet, and was normal after wine supplementation. These effects are attributed to oxidative stress associated with a high fat diet, and to the elevated plasma antioxidant capacity associated with wine consumption and the Mediterranean diet. The results presented support the following conclusions: a high fat diet induces oxidative stress; a diet rich in fruits and vegetables enhances antioxidant defenses; wine supplementation to a high fat or a Mediterranean diet increases plasma antioxidant capacity, decreases oxidative DNA damage, and normalizes endothelial function.     

Risk assessment of low arsenic exposure using biomarkers of oxidative and genotoxic stress in a piscine model

The high level exposure to arsenic induces marked oxidative and genotoxic stress. However, information on the potential of low level arsenic exposure in this context is still scanty. In the present study, the extent of oxidative stress and genetic toxicity induced by low arsenic exposure was explored in freshwater fish Channa punctatus. Fish were exposed to low levels of arsenic (10 and 50 µg L⁻¹) as well as to its high level (500 µg L⁻¹) using sodium arsenite in aquaria water for 14 consecutive days. The TBARS assay for lipid peroxidation exhibited the increased occurrence of oxidative damage in the erythrocytes of fish at both the lower and higher levels of arsenic exposure. The level of reduced glutathione was also elevated in all the three arsenic exposed groups of fish compared to control. In contrast, significant decline was observed in the levels of three major antioxidant enzymes namely, superoxide dismutase, catalase and glutathione peroxidase, upon exposure to higher as well as lower levels of arsenic. Significant increases in micronucleus induction were found in the erythrocytes of fish even at the low levels of arsenic exposure. The study further revealed the occurrence of DNA fragmentation in the erythrocytes of fish at low arsenic exposures as well. The low level exposure to arsenic (using sodium arsenite), therefore, appeared to be capable of inducing noticeable oxidative stress as well as potential genotoxic effect in Channa punctatus. Moreover, the ability of arsenic to induce oxidative stress invariably appeared correlated with its genotoxic potential.

     

The safety of ethyl oleate is supported by a 91-day feeding study in rats

The purpose of this study was to determine the safety of ethyl oleate (EO) in a 91-day feeding study in Sprague-Dawley rats. EO was mixed into AIN-93G purified diet at levels of 0, 3.3, 6.7, and 10% by weight (the high-dose males and females consumed 5.5 and 6.1g/kg/day EO, respectively). All diets were calorie- and fat-matched using high oleic safflower oil (HOSO) as the control fat. The study design followed the 1993 FDA draft "Redbook II" guidelines (Toxicological Principles for the Safety Assessment of Direct Food Additives and Color Additives Used in Food). There were 20 male and 20 female rats per group. EO in the diet was well tolerated and there were no toxicologically significant findings in any of the measured parameters (clinical observations, body weight gains, appearance of the feces, ophthalmic examinations, hematology, clinical chemistry, urinalysis, organ weights, histopathology, or male and female reproductive assessments). Mortality was limited to three males during the course of the study whose cause of death was unrelated to test material administration. The terminal body weight of the mid- and high-dose females was approximately 10% lower than that of the control group. This finding does not represent a toxicologically significant effect because rats on the EO diets gained more weight during the course of the study than historical control data on this strain of rats. The lower body weight relative to control rats is directly related to lower food consumption relative to the controls. The lower food consumption relative to controls is fully consistent with a decrease in the palatability of the EO-containing food versus the triglyceride-containing food. This conclusion is based on (1) a decrease in food consumption was noted within the first week (consistent with palatability preferences), (2) there was not a dose-response with regard to food consumption (mid-dose consumed less than high-dose), (3) the lack of cumulative decreases in food consumption which often are observed with toxicity, and (4) anecdotal experiences in our lab show that rats prefer diets containing high triglyceride fat over high EO-fat. Hepatocellular vacuolation typical of fat accumulation was noted for both control and high-dose animals. The incidence and severity of the vacuolation were higher for animals given 10% HOSO (controls) than for the animals given 10% EO. Serum calcium and phosphorous levels in high dose males were slightly, but statistically significantly, lower than in the controls. There was a dose-related increase in fecal fat concentration in both sexes from approximately 9% (control) to 18% in males, and from 4 (control) to 13% in females There were no visually obvious differences with regard to feces quality or quantity at any level of EO in the diet (i.e., color, diarrhea, weight, etc.). The increase in fat most likely represents small amounts of unabsorbed EO at the mid- and high-dose (estimates of EO absorption in this study are >80%). The No Observable Adverse Effect Level was determined to be 10% EO when administered daily in the diet for 91-days (approximately 6g EO/kg bw/day).     

Protective effects of melatonin and glucagon‐like peptide‐1 receptor agonist (liraglutide) on gastric ischaemia–reperfusion injury in high‐fat/sucrose‐fed rats

Ischaemia–reperfusion (I–R) injury is a serious pathology that is often encountered with thrombotic events, during surgery when blood vessels are cross‐clamped, and in organs for transplantation. Increased oxidative stress is the main pathology in I–R injury, as assessed in studies on the heart, kidney, and brain with little data available on gastric I–R (GI–R). Liraglutide is a GLP‐1 receptor agonist that has insulinotropic and weight reducing actions, and melatonin that has been much studied as a chronotropic hormone; have also studied as being anti‐oxidative stress agents. Herein, we aimed to explore the effects of liraglutide and melatonin on GI–R injury with high‐fat/sucrose diet. Rats were divided into six groups; two diet‐control, two melatonin‐ and two liraglutide‐pretreated groups. All rats were subjected to 30 minutes of gastric ischaemia followed by 1 hour of reperfusion. Gastric tissues were assessed for the percentage of DNA fragmentation, myeloperoxidase activity, total oxidant status, total antioxidant capacity, oxidative stress index, BMI and histopathological examination. We showed that high‐fat feeding for four weeks prior to GI–R significantly increased BMI, oxidative stress indices and decreased total antioxidant capacity, with a neutral effect on apoptosis compared to controls. Pretreatment with either melatonin (10 mg/kg per day orally) or liraglutide (25 μg/kg per day ip) reverses these effects. Furthermore, both drugs reduced weight only in HFS‐fed rats. Both liraglutide and melatonin have nearly similar protective effects on gastric I–R injury through decreasing the oxidative stress and apoptosis.