氧化应激在高脂高盐饮食伴高糖饮水诱导的代谢综合征肾病大鼠中的作用

目的: 构建饮食诱导的代谢综合征(MS)肾病大鼠模型,并探讨氧化应激在肾脏损伤中的作用。方法: 7周龄雄性SD大鼠随机分为正常对照组(n=10)和MS模型组(n=10)。MS大鼠喂饲高脂高盐(HFS)饲料和20%蔗糖饮水20周。测定尾动脉收缩压(SBP);测空腹血糖(FBG)、血脂和胰岛素(FIns)水平,计算稳态胰岛素评价指数(HOMA-IR);测肌酐、尿蛋白、尿白蛋白和尿钠含量,并计算肌酐清除率(Ccr)、蛋白排泄率(UPE)、白蛋白排泄率(UAE)和钠排泄率(USE);测肾脏组织总抗氧化能力(T-AOC)、抑制超氧阴离子能力(ISAC)、丙二醛(MDA)含量以及抗氧化酶活性;Western blotting检测肾脏铜锌超氧化物歧化酶(Cu/Zn-SOD) 和NADPH氧化酶亚单位p47^phox、p22^phox蛋白表达;PAS和Masson染色观察肾脏病理变化并进行评分。结果: 与正常组相比,MS大鼠SBP、血脂、FIns、HOMA-IR、USE和UAE增高;肾脏T-AOC、ISAC和SOD活性降低,MDA含量增加;p47^phox蛋白表达增高,Cu/Zn-SOD蛋白表达降低;肾小球硬化评分升高。结论: 喂饲大鼠HFS饮食和高糖饮水可建立模拟大部分临床特征的MS肾病模型。NADPH氧化酶表达增高和SOD表达减少而引起的氧化应激是导致MS大鼠肾脏损伤的机制之一。     

Involvement of catalase in the protective effect of binaphthyl diselenide against renal damage induced by glycerol

In the present study, the protective effect of binapthyl diselenide [(NapSe)₂] was investigated on glycerol-induced renal damage in rats. Adult male Wistar rats were treated with (NapSe)₂ (50 mg/kg, orally) or vehicle. After 24 h (NapSe)₂ treatment, the animals received an intramuscular injection of glycerol (8 ml/kg, dissolved in saline) or vehicle as a divided dose into the hind limbs. Twenty-four hours afterwards, rats were euthanized and the levels of urea and creatinine were measured in plasma. Non-protein thiol (NPSH) levels and catalase (CAT) activity were evaluated in renal homogenates. Histopathological evaluations were also performed in kidneys of rats. The rats exposed to glycerol presented swelling of the proximal and distal tubules with evidence of cell damage and death. Glycerol-exposed rats presented an increase in renal failure markers (plasmatic urea and creatinine levels) and a reduction in renal CAT activity. No change was observed in NPSH levels in kidneys of rats exposed to glycerol. (NapSe)₂ protected against the alterations caused by glycerol in rats. (NapSe)₂ increased per se NPSH levels (33%) in kidneys of rats. In conclusion, the results demonstrated that treatment with (NapSe)₂ protected against renal damage induced by glycerol in rats, probably due to its antioxidant effect.     

Anti-inflammatory properties of culinary herbs and spices that ameliorate the effects of metabolic syndrome

Obesity and metabolic syndrome are increasing global health problems. In addition to the malnutrition of a sedentary lifestyle, high calorie intake leads to obesity with many negative health consequences. Macrophages infiltrate adipose tissue and induce chronic inflammation by secreting pro-inflammatory cytokines, including COX-2 and iNOS, among other mediators of inflammation. Free fatty acids mediate adipose tissue signalling through toll-like receptor 4 and the expression of these pro-inflammatory mediators via NF-κB or JNK. PPAR γ activators can inhibit the activation of NF-κB, down-regulating the expression of pro-inflammatory cytokines. Here we provide an overview of how different culinary herbs and spices exert anti-inflammatory activities and the extent to which they activate PPAR α and PPAR γ, inhibit the activation of NF-κB, and enhance expression of anti-inflammatory cytokines. Spices can play essential roles as anti-inflammatory agents in our diet, acting as pan PPAR activators and improving insulin sensitivity, counteracting dyslipidaemia and weight gain. The effects of chronic inflammation caused by obesity are counteracted and, consequently, the progression of diseases associated with chronic inflammation slowed.     

Associations of visceral fat,physical activity and muscle strength with the metabolic syndrome

Objective

We investigated the association of visceral fat with the metabolic syndrome (MetS) and its separate components; the associations of both physical activity and muscle strength with the MetS and its separate components independent of visceral fat. Furthermore, we studied these associations within participants with low and high amounts of visceral fat.

Study design

400 men (aged 40–80 years) were recruited into a cross-sectional study.Main outcome measures: Logistic regression models were used to study the individual associations in all participants (OR). The associations of physical activity (active vs inactive) and muscle strength (high vs low) within participants with low and high levels of visceral fat (assessed by ultrasonography) were tested using Univariate Analysis of Variance (difference in mean levels of the separate components of MetS) and logistic regression (risk on MetS).

Results

High levels of visceral fat were significantly associated with increased risk of MetS (OR 1.7 95%CI 1.5;1.9) and its separate components (p < 0.05). We did not find strong individual associations for physical activity or muscle strength, neither within men with low or high levels of visceral fat.

Conclusions

High body fat levels were associated with an unhealthier metabolic risk profile and a higher risk of the MetS. Our cross-sectional data do not indicate associations for physical activity or for muscle strength with the MetS independent of visceral fat. Also no differential associations of physical activity or muscle strength in men with low or high levels of visceral fat were found.     

Protective effects of the citrus flavanones to PC12 cells against cytotoxicity induced by hydrogen peroxide

Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities. One of the plausible ways to prevent the reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical augmentation of endogenous antioxidant defense capacity. In this study, we investigated the protective actions of citrus flavanones naringin and nobiletin against the cytotoxicity induced by exposure to hydrogen peroxide (H₂O₂) (150 μM, 3 h) in PC12 cells. The results showed that naringin and nobiletin inhibited the decrease of cell viability (MTT reduction), prevented membrane damage (LDH release), scavenged ROS formation, reduced caspase-3 activity, and attenuated the decrease of mitochondrial membrane potential (MMP), respectively, in H₂O₂-induced PC12 cells. Meanwhile, naringin and nobiletin increased superoxide dismutase (SOD) and glutathione (GSH) activity, while decreased malondialdehyde (MDA), the production of lipid peroxidation, in H₂O₂-induced PC12 cells. In addition, the percentage of cells undergoing H₂O₂-induced apoptosis was decreased in the presence of naringin and nobiletin. These results first demonstrate that naringin and nobiletin, even at physiological concentrations, have neuroprotective effects against H₂O₂-induced cytotoxicity in PC12 cells. All the above results suggest that these dietary antioxidants are potential candidates for use in the intervention for neurodegenerative diseases.     

Identifying subjects with insulin resistance by using the modified criteria of metabolic syndrome

The objectives of this cohort analysis were to explore the relationship between insulin resistance (IR) and the criteria for metabolic syndrome (MetS) and to evaluate the ability to detect IR in subjects fulfilling those criteria. We enrolled 511 healthy subjects (218 men and 283 women) and measured their blood pressure (BP), body mass index, high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and fasting plasma glucose levels. Insulin suppression testing was done to measure insulin sensitivity as the steady-state plasma glucose (SSPG) value. Subjects with an SSPG value within the top 25% were considered to have IR. The commonest abnormality was a low HDL-C level, followed by high BP. The sensitivity to detect IR in subjects with MetS was about 47%, with a positive predictive value of about 64.8%, which has higher in men than in women. In general, the addition of components to the criteria for MetS increased the predictive value for IR. The most common combination of components in subjects with MetS and IR were obesity, high BP, and low HDL-C levels. All of the components were positive except for HDL-C, which was negatively correlated with SSPG. The correlation was strongest for obesity, followed by high TG values. In subjects with MetS, sensitivity for IR was low. However, body mass index and TG values were associated with IR and may be important markers for IR in subjects with MetS.     

The protective effects of vitamin C on the DNA damage,antioxidant defenses and aorta histopathology in chronic hyperhomocysteinemia induced rats

The aim of this study was to investigate the protective effect of vitamin C towards hyperhomocysteinemia (hHcy) induced oxidative DNA damage using the comet assay. The increase in plasma homocysteine levels is an important risk factor for vascular and cardiovascular diseases through free radical production. This study was also conducted to investigate the histopathological changes in the thoracic aorta and the oxidant/antioxidant status in heart, liver and kidney tissues.Twenty-four adult male Wistar rats were divided as control, hHcy and hHcy + vitamin C group. Chronic hHcy was induced by oral administration of l-methionine (1 g/kg/day) for 28 days. Vitamin C was given 150 mg/kg/day within the specified days. DNA damage was measured by use of the comet assay in lymphocytes. Levels of malondialdehyde (MDA) and glutathione (GSH) as well as catalase (CAT) and superoxide dismutase (SOD) activities were determined in heart, liver and renal tissues.Results show that l-methionine administration significantly increased % Tail DNA and Mean Tail Moment in hHcy group as compared with other groups. Vitamin C treatment significantly decreased the high MDA levels and increased activity of antioxidant enzymes in tissues. Aortic diameter and thickness of aortic elastic laminae were significantly lower in hHcy + vitamin C group.Comet assay can be used for the assessment of primary DNA damage caused by hHcy. Histopathological findings showed that vitamin C may have a preventive effect in alleviating the negative effects of hHcy. Vitamin C might be useful in the prevention of endothelial dysfunction caused by hHcy.     

Obesity is associated with insulin resistance and components of the metabolic syndrome in Lebanese adolescents

Background: Prevalence of metabolic syndrome (MS) in obese adolescents has been reported to range between 18–42%, depending on country of origin, thus suggesting an ethnic-based association between obesity and MS.

Aim: This study aims to investigate the magnitude of the association between obesity, insulin resistance and components of MS among adolescents in Lebanon.

Subjects and methods: The sample included 263 adolescents at 4^th and 5^th Tanner stages of puberty (104 obese; 78 overweight; 81 normal weight). Anthropometric, biochemical and blood pressure measurements were performed. Body fat was assessed using dual-energy X-ray absorptiometry.

Results: According to International Diabetes Federation criteria, MS was identified in 21.2% of obese, 3.8% of overweight and 1.2% of normal weight subjects. The most common metabolic abnormalities among subjects having MS were elevated waist circumference (96.2%), low HDL (96.2%) and hypertriglyceridemia (73.1%). Insulin resistance was identified in all subjects having MS. Regression analyses showed that percentage body fat, waist circumference and BMI were similar in their ability to predict the MS in this age group.

Conclusions: MS was identified in a substantial proportion of Lebanese obese adolescents, thus highlighting the importance of early screening for obesity-associated metabolic abnormalities and of developing successful multi-component interventions addressing adolescent obesity.     

The role of epidermal growth factor in prevention of oxidative injury and apoptosis induced by intestinal ischemia/reperfusion in rats

Intestinal ischemia/reperfusion is a major problem which may lead to multiorgan failure and death. The aim of the study was to evaluate the effects of epidermal growth factor (EGF) on apoptosis, cell proliferation, oxidative stress and the antioxidant system in intestinal injury induced by ischemia/reperfusion in rats and to determine if EGF can ameliorate these toxic effects. Intestinal ischemia/reperfusion injury was produced by causing complete occlusion of the superior mesenteric artery for 60 min followed by a 60-min reperfusion period. Animals received intraperitoneal injections of 150 μg/kg human recombinant EGF 30 min prior to the mesenteric ischemia/reperfusion. Mesenteric ischemia/reperfusion caused degeneration of the intestinal mucosa, inhibition of cell proliferation, stimulation of apoptosis and oxidative stress in the small intestine of rats. In the ischemia/reperfusion group, lipid peroxidation was stimulated accompanied by increased intestinal catalase and glutathione peroxidase activities, however, glutathione levels and superoxide dismutase activities were markedly decreased. EGF treatment to rats with ischemia/reperfusion prevented the ischemia/reperfusion-induced oxidative injury by reducing apoptosis and lipid peroxidation, and by increasing antioxidant enzyme activities. These results demonstrate that EGF has beneficial antiapoptotic and antioxidant effects on intestinal injury induced by ischemia/reperfusion in rats.     

The Apolipoprotein B/Apolipoprotein A 1 ratio in relation to metabolic syndrome and its components in a sample of the Tunisian population

Objective

This study was undertaken to investigate the relationship between the Apolipoprotein B/Apolipoprotein A 1 (ApoB/ApoA 1) ratio and various characteristics of the metabolic syndrome (MetS) in a sample of the Tunisian population.

Methods

The study included 330 adults aged 35–74 (172 patients with MetS and 158 controls). Waist circumference (WC), blood pressure (BP), HDL-cholesterol (HDL-C), triglycerides (TG), glucose, insulin, and apolipoprotein concentrations were measured. Homeostasis model assessment (HOMA) was used to assess insulin resistance (IR). MetS was defined by NCEP-ATPIII report.

Results

The ApoB/ApoA 1 ratio was significantly higher in patients with MetS versus normal control subjects (p < 0.001). Mean values of ApoB/ApoA 1 ratio increased significantly as the numbers of MetS components increased in men (p < 0.001) and women (p < 0.001). ApoB/ApoA 1 ratio showed statistically significant associations with WC, HDL-C, TG, systolic and diastolic BP, and HOMA-IR. After adjusting for age and gender, the high ApoB/ApoA 1 ratio was significantly associated with the presence of MetS (odds ratio [OR] = 6.10), IR (OR = 1.88), and with each of the MetS components, including: high WC (OR = 2.43), High TG (OR = 6.14), and low HDL-C (OR = 6.92).

Conclusions

Our findings suggest that the ApoB/ApoA 1 ratio is strongly associated with MetS and its components, as well as with IR.     

PLA2G2A polymorphisms are associated with metabolic syndrome and type 2 diabetes mellitus. Results from the genetics of atherosclerotic disease Mexican study

The secretory phospholipase A₂ II A (sPLA₂-IIA) encoded by PLA2G2A gene hydrolyzes phospholipids liberating free fatty acids (FFAs) and lysophospholipids. If lipolysis exceeds lipogenesis, the free fatty acids undergo a continuous release into circulation. A sustained excessive increase in this release contributes to metabolic disease. The aim of the present study was to evaluate the role of PLA2G2A gene polymorphisms as susceptibility markers for metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) in Mexican population. Three PLA2G2A gene polymorphisms (rs876018, rs3753827 and rs11573156) were genotyped by 5′ exonuclease TaqMan assays in a group of 338 patients with T2DM, 460 individuals with MetS and 366 healthy controls. Under codominant 1 (codom1), dominant (dom) and additive (add) models adjusted by age, gender, body mass index (BMI), smoking habit, and hypertension, the rs876018 T allele was associated with increased risk of MetS [Odds Ratio (OR) = 1.66, P_codom1 = 0.005; OR = 1.67, P_dom = 0.003; OR = 1.49, P_add = 0.005] as compared to controls. On the other hand, under several models adjusted by the same variables, the rs3753827 A (OR = 1.52, P_codom1 = 0.039 and OR = 1.49, P_dom = 0.039) and rs11573156C alleles (OR = 6.46, P_codom1 = 0.013; OR = 6.70, P_codom2 = 0.009; OR = 6.65, P_dom = 0.009) were associated with increased risk of T2DM when compared with controls. In addition, the rs876018 T allele was associated with hypercholesterolemia (P_dom = 0.017, P_add = 0.009) and risk of subclinical atherosclerosis (SA) (P_dom = 0.041) in MetS when compared with controls. Also, this allele was associated with SA in T2DM patients (P_dom = 0.007). The TAG haplotype was significantly associated with increased risk of MetS (OR = 1.54, P = 0.006). Results suggest that PLA2G2A polymorphisms are involved in the risk of developing MetS and T2D and are associated with SA in this group of patients.     

热休克蛋白90在硫化氢抗化学性缺氧诱导心肌细胞氧化应激损伤中的作用

目的： 探讨热休克蛋白90（HSP90）在硫化氢（H2S）对抗化学性低氧模拟剂氯化钴（CoCl2）诱导H9c2心肌细胞氧化应激损伤中的作用。方法： 应用CoCl2处理H9c2心肌细胞,建立化学性缺氧损伤心肌细胞的实验模型。在CoCl2处理H9c2心肌细胞前30 min,把硫氢化钠（NaHS,H2S的供体）加入培养基中,作为预处理。应用高效液相色谱法（HPLC）检测细胞内ATP的含量;罗丹明123（Rh123）染色荧光显微镜照相检测线粒体膜电位（MMP）;超氧化物歧化酶（SOD）检测试剂盒检测SOD活性;免疫印迹法（Western blotting）检测血红素氧合酶-1（HO-1）的表达。结果： 600 μmol/L CoCl2明显地降低H9c2心肌细胞内SOD活性、ATP水平及MMP,并增加HO-1表达。400 μmol/L NaHS 预处理可显著地抑制CoCl2诱导的细胞毒性及氧化应激反应,使SOD活性、ATP水平及MMP提高,HO-1表达减少。热休克蛋白90抑制剂17-丙烯胺基-17去甲氧基格尔德霉素（17AAG）能明显地阻断H2S对CoCl2诱导的细胞毒性和氧化应激反应的抑制作用,使细胞内ATP水平及MMP降低,HO-1表达增多,但对SOD活性的影响不明显。结论： 热休克蛋白90可通过抑制化学性缺氧引起的氧化应激反应来介导H2S的心肌保护作用。     

Aquilegia vulgaris extract protects against the oxidative stress and the mutagenic effects of cadmium in Balb/c mice

Cadmium (Cd) is a non-essential element and is a widespread environmental pollutant. Exposure to cadmium can result in cytotoxic, carcinogenic and mutagenic effects. The aim of the current work was to evaluate the protective effect of Aquilegia vulgaris extract against the oxidative stress and the genotoxicity induced by Cd using the chromosomal aberrations in somatic and germ cells assay and random amplified polymorphism DNA (RAPD-PCR) analysis. Forty male Balb/c mice were divided into four groups including the control group, Cd-treated group and the groups treated with the extract alone or plus Cd. The results indicated that Cd increased serum ALT, AST, urea, LDH, CK, lipid peroxidation in liver tissue accompanied with a significant decrease in GPX and SOD. Cd also increased the number of chromosomal aberrations in bone marrow and spermatocytes including structural and numerical aberrations. Animals treated with the extract alone were comparable to the control regarding all the tested parameters. The extract succeeded in preventing or diminishing the oxidative stress and the clastogenic effects of Cd. It could be concluded that Aquilegia vulgaris extract is a promising protective agent against oxidative stress and genotoxicity during the exposure to Cd.     

Irisin protects against neuronal injury induced by oxygen-glucose deprivation in part depends on the inhibition of ROS-NLRP3 inflammatory signaling pathway

Recent studies found that irisin, a newly discovered skeletal muscle-derived myokine during exercise, is also synthesized in various tissues of different species and protects against neuronal injury in cerebral ischemia. The NOD-like receptor pyrin 3 (NLRP3) inflammasome play an important role in detecting cellular damage and mediating inflammatory responses to aseptic tissue injury during ischemic stroke. However, it is unclear whether irisin is involved in the regulation of NLRP3 inflammasome activation during ischemic stroke. In the present study, PC12 neuronal cells were exposed to oxygen-glucose deprivation (OGD), exogenous irisin (12.5, 25, 50 nmol/L) or NLRP3 inhibitor glyburide (50, 100, 200 μmol/L) were used as an intervention reagent, NLRP3 was over-expressed or suppressed by transfection with a NLRP3 expressing vector or NLRP3-specifc siRNA, respectively. Our data showed that both irisin and its precursor protein fibronectin type III domain containing 5 (FNDC5) expression were significantly down-regulated (p < 0.05); but oxidative stress and ROS-NLRP3 inflammasome signaling were activated by OGD (p < 0.05); treatment with irisin or inhibition of NLRP3 reversed OGD-induced oxidative stress and inflammation (p < 0.05). However, these irisin-mediated effects were blunted by over-expression NLRP3 (p < 0.05). Taken together, our results firstly revealed that irisin mitigated OGD-induced neuronal injury in part via inhibiting ROS-NLRP3 inflammatory signaling pathway, suggesting a likely mechanism for irisin-induced therapeutic effect in ischemic stroke.     

The oxidative stress induced in vivo by Shiga toxin‐2 contributes to the pathogenicity of haemolytic uraemic syndrome

Typical haemolytic uraemic syndrome (HUS) is caused by Shiga toxin (Stx)‐producing Escherichia coli infections and is characterized by thrombotic microangiopathy that leads to haemolytic anaemia, thrombocytopenia and acute renal failure. Renal or neurological sequelae are consequences of irreversible tissue damage during the acute phase. Stx toxicity and the acute inflammatory response raised by the host determine the development of HUS. At present there is no specific therapy to control Stx damage. The pathogenic role of reactive oxygen species (ROS) on endothelial injury has been largely documented. In this study, we investigated the in‐vivo effects of Stx on the oxidative balance and its contribution to the development of HUS in mice. In addition, we analysed the effect of anti‐oxidant agents as therapeutic tools to counteract Stx toxicity. We demonstrated that Stx induced an oxidative imbalance, evidenced by renal glutathione depletion and increased lipid membrane peroxidation. The increased ROS production by neutrophils may be one of the major sources of oxidative stress during Stx intoxication. All these parameters were ameliorated by anti‐oxidants reducing platelet activation, renal damage and increasing survival. To conclude, Stx generates a pro‐oxidative state that contributes to kidney failure, and exogenous anti‐oxidants could be beneficial to counteract this pathogenic pathway.