Grape seed extract supplementation prevents high-fructose diet-induced insulin resistance in rats by improving insulin and adiponectin signalling pathways

Recent evidence strongly supports the contention that grape seed extract (GSE) improves hyperglycaemia and hyperinsulinaemia in high-fructose-fed rats. To explore the underlying molecular mechanisms of action, we examined the effects of GSE on the expression of muscle proteins related to the insulin signalling pathway and of mRNA for genes involved in the adiponectin signalling pathway. Compared with rats fed on a normal diet, high-fructose-fed rats developed pathological changes, including insulin resistance, hyperinsulinaemia, hypertriacylglycerolaemia, a low level of plasma adiponectin and a high level of plasma fructosamine. These disorders were effectively attenuated in high-fructose-fed rats supplemented with GSE. A high-fructose diet causes insulin resistance by significantly reducing the protein expression of insulin receptor, insulin receptor substrate-1, Akt and GLUT4, and the mRNA expression of adiponectin, adiponectin receptor R1 (AdipoR1) and AMP-activated protein kinase (AMPK)-α in the skeletal muscle. Supplementation of GSE enhanced the expression of insulin signalling pathway-related proteins, including Akt and GLUT4. GSE also increased the mRNA expression of adiponectin, AdipoR1 and AMPK-α. In addition, GSE increased the mRNA levels of glycogen synthase and suppressed the mRNA expression of glycogen synthase kinase-3-α, causing an increase in glycogen accumulation in the skeletal muscle. These results suggest that GSE ameliorates the defective insulin and adiponectin signalling pathways in the skeletal muscle, resulting in improved insulin resistance in fructose-fed rats.     

缺锌及不同补锌方式仔鼠海马超微结构的改变

【目的】研究孕期和哺乳期母鼠缺锌及不同补锌方式,对仔鼠海马神经元及血脑屏障超微结构的影响。【方法】怀孕1 d的孕鼠随机分为2组,每组3只:对照组,缺锌组,口服补锌组,注射补锌组。对照组自由食用正常饲料(含锌25 mg/kg);其它3组自由食用缺锌饲料(含锌5 mg/kg)。产后每窝各保留体重相近的3只。至21 d断乳仔鼠:对照组继续饲以正常饲料;缺锌组继续饲以缺锌饲料;口服补锌组改饲以正常饲料;注射补锌组继续饲以缺锌饲料并腹腔注射硫酸锌溶液。实验期至仔鼠35 d龄。海马CA3区组织切片及透射电镜观察超微结构的改变。【结果】缺锌组:电镜下神经元明显皱缩,核不规则形、异染色质散在分布。胞质中线粒体肿胀、嵴脱失,粗面内质网有扩张;毛细血管管腔充盈,内皮细胞线粒体肿胀,周围原浆型星形胶质细胞的胞体明显空泡样改变。口服补锌组神经元细胞及血脑屏障超微结构基本同对照组。注射补锌组海马神经元细胞及血脑屏障超微结构基本同缺锌组。【结论】生命早期缺锌可使大鼠海马神经元及血脑屏障发生病理改变,合适的补锌方式可逆地修复仔鼠海马超微结构的改变。     

Acute stress modifies food choice in Wistar male and female rats

The present study investigates the effects of acute stress (15 min of swimming/day for three consecutive days) applied at the onset of the dark phase, just before the usual feeding time, on energy intake and more specifically on macronutrient selection, in male and female Wistar rats. The influence of stress regarding corticosterone and insulin kinetics was also examined. In the two experiments (1: food ad lib and 2: two feeding periods/day), three consecutive days of stress reduced daily body weight gain for both sexes. In the first experiment, the reduction in energy intake only occurred during the first 3h after stress. In males the 3h decrease in energy intake affected the three macronutrients, while in females, only the fat intake was decreased. In the second experiment, the stress only affected intake during the first feeding period. Protein, fat and CHO intakes were reduced in males, while in females only the protein and fat intakes were decreased. Unlike males, an increase in fat ingestion was observed in females; this occurred 6h after stress in experiment 1 and during the second feeding period 5h after stress in experiment 2. Stress raised plasma corticosterone levels in both sexes, while plasma insulin levels were decreased. These results demonstrate that the response to stress differed in males and females regarding macronutrient selection. Moreover, stress induced not only a quantitative effect on energy intake but also a qualitative one.     

Effects of a nutritional supplement containing Salacia oblonga extract and insulinogenic amino acids on postprandial glycemia, insulinemia, and breath hydrogen responses in healthy adults

OBJECTIVE: This study evaluated the postprandial glycemic, insulinemic, and breath hydrogen responses to a liquid nutritional product containing Salacia oblonga extract, an herbal alpha-glucosidase inhibitor, and two insulinogenic amino acids. METHODS: In a randomized, double-masked, crossover design, 43 healthy subjects were fed the following meals on separate days after overnight fasting: control (C; 480 mL of a study beverage containing 82 g of carbohydrate, 20 g of protein, and 14 g of fat), control plus 3.5 g each of phenylalanine and leucine (AA), control plus 1000 mg of S. oblonga extract (S), and control plus S and AA (SAA). Postprandially, fingerstick capillary plasma glucose and venous serum insulin levels were measured for 180 min, and breath hydrogen excretion was measured for 480 min. RESULTS: The baseline-adjusted peak glucose response was not different across meals. However, changes in plasma glucose areas under the curve (0 to 120 min and 0 to 180 min, respectively) compared with C were -9% and -11% for AA (P>0.05 each), -27% and -24% for S (P=0.035 and 0.137), and -27% and -29% for SAA (P<0.05 each). Changes in insulin areas under the curve were +5% and +5% for AA (P>0.05 each), -35% and -36% for S (P<0.001 each), and -6% and -7% for SAA (P>0.05 each). Breath hydrogen excretion was 60% greater (P<0.001) in the S-containing meals than in the C- and AA-containing meals and was associated with mild flatulence. CONCLUSIONS: Salacia oblonga extract is a promising nutraceutical ingredient that decreased glycemia in this study. Supplementation with amino acids had no significant additional effect on glycemia.     

Whey-hydrolyzed peptide-enriched immunomodulating diet prevents progression of liver cirrhosis in rats

ObjectiveLiver fibrosis and subsequent cirrhosis is a major cause of death worldwide, but few effective antifibrotic therapies are reported. Whey-hydrolyzed peptide (WHP), a major peptide component of bovine milk, exerts anti-inflammatory effects in experimental models. A WHP-enriched diet is widely used for immunomodulating diets (IMD) in clinical fields. However, the effects of WHP on liver fibrosis remain unknown. The aim of this study was to investigate the antifibrotic effects of WHP in a rat cirrhosis model.MethodsProgressive liver fibrosis was induced by repeated intraperitoneal administration of dimethylnitrosamine (DMN) for 3 wk. Rats were fed either a WHP-enriched IMD (WHP group) or a control enteral diet (control group). The degree of liver fibrosis was compared between groups. Hepatocyte-protective effects were examined using hepatocytes isolated from rats fed a WHP diet. Reactive oxygen species and glutathione in liver tissue were investigated in the DMN cirrhosis model.ResultsMacroscopic and microscopic progression of liver fibrosis was remarkably suppressed in the WHP group. Elevated serum levels of liver enzymes and hyaluronic acid, and liver tissue hydroxyproline content were significantly attenuated in the WHP group. Necrotic hepatocyte rates with DMN challenge, isolated from rats fed a WHP-enriched IMD, were significantly lower. In the DMN cirrhosis model, reactive oxygen species were significantly lower, and glutathione was significantly higher in the WHP group’s whole liver tissue.ConclusionA WHP-enriched IMD effectively prevented progression of DMN-induced liver fibrosis in rats via a direct hepatocyte-protective effect and an antioxidant effect through glutathione synthesis.     

Effect of a milk-based food supplement on maternal nutritional status and fetal growth in underweight Chilean women

The effects on pregnancy outcome and maternal iron status of powdered milk (PUR) and a milk-based fortified product (V-N) were compared in a group of underweight gravidas. These take-home products were distributed during regular prenatal visits. Women in the V-N group had greater weight gain (12.29 vs 11.31 kg, p less than 0.05) and mean birth weights (3178 vs 3105 g, p less than 0.05) than those in the PUR group. Values for various indicators of maternal Fe status were also higher in the V-N group. Compared with self-selected noncompliers, similar in all control variables to compliers, children of women who consumed powdered milk or the milk-based fortified product had mean birth weights that were higher by 258 and 335 g, respectively. Data indicate a beneficial effect of the fortified product on both maternal nutritional status and fetal growth.     

Pomegranate seed extract attenuates chemotherapy-induced acute nephrotoxicity and hepatotoxicity in rats

Cisplatin (CDDP), one of the most active cytotoxic agents against cancer, has adverse side effects, such as nephrotoxicity and hepatotoxicity. The present study was designed to investigate the potential protective effect of pomegranate seed extract (PSE) against oxidative stress caused by CDDP injury of the kidneys and liver by measuring tissue biochemical and antioxidant variables and immunohistochemically testing caspase-3-positive cells. Twenty-four Sprague-Dawley rats were divided into 4 groups: control; CDDP: injected intraperitoneally with CDDP (7 mg/kg body weight, single dose); PSE: treated for 15 consecutive days by gavage with PSE (300 mg/kg per day); and PSE+CDDP: treated by gavage with PSE 15 days after a single injection of CDDP. The degree of protection against CDDP injury afforded by PSE was evaluated by determining the levels of malondialdehyde as a measure of lipid peroxidation. The levels of glutathione and activities of glutathione peroxidase, glutathione S-transferase, and superoxide dismutase were estimated from liver and kidney homogenates; the liver and kidney were also histologically examined. PSE elicited a significant protective effect toward liver and kidney by decreasing the level of lipid peroxidation; elevating the levels of glutathione S-transferase; and increasing the activities of glutathione peroxidase, glutathione S-transferase, and superoxide dismutase. These biochemical observations were supported by immunohistochemical findings and suggested that PSE significantly attenuated nephrotoxicity and hepatotoxicity by the way of its antioxidant, radical-scavenging, and antiapoptotic effects. This PSE extract could be used as a dietary supplement in patients receiving chemotherapy medications.     

不同锌营养状况对大鼠铁代谢的影响

目的研究不同锌营养状况对大鼠铁代谢和肝脏铁调节蛋白(IRP)mRNA、铁蛋白(Fn)mRNA及转铁蛋白受体(TfR)mRNA的影响。方法 40只雄性SD大鼠按体重随机分为4组,每组10只,铁和锌正常对照组(ZA组),铁正常锌缺乏组(ZD组),铁和锌正常配饲组(PF组),铁正常锌过量组(ZE组)。喂饲8周后麻醉处死,取大鼠肝脏、脾脏和血清,测定血红蛋白,血清锌、血清铁、血清转铁蛋白受体、血清铁蛋白、肝脏铁和锌含量、脾脏铁和锌含量,并用逆转录-聚合酶链反应(RT-PCR)法检测各组大鼠IRP2 mRNA和肝脏TfR mRNA以及Fn mRNA的表达水平。结果与对照组相比,锌过量使肝脏和脾脏铁含量、血清铁水平显著降低(P<0.05);锌缺乏使肝脏铁含量、血清转铁蛋白受体水平显著增高(P<0.05),同时,血清铁水平显著降低(P<0.05);锌缺乏时肝脏IRP mRNA及TfR mRNA表达显著增强。结论锌缺乏可能通过影响铁吸收、储存、转运来影响体内铁的营养状况。锌缺乏通过改变IRP2表达、IRP-RNA结合活性,在转录后水平改变TfR mRNA和FnmRNA表达,影响铁稳态。     

Hypolipidemic and antioxidant potentials of Xylopia aethiopica seed extract in hypercholesterolemic rats

A short-term study was carried out on Wistar strain rats to determine the effects of Xylopia aethiopica extract on serum and postmitochondrial fractions (PMFs) of visceral organs in experimental hypercholesterolemia. Animals received normal diet and were administered cholesterol orally by intubations at a dose of 40?mg/kg/0.3?mL, plant extracts at 250?mg/kg, and cholestyramine (Questran?, Bristol-Myers Squibb, Hounslow, United Kingdom) at 0.26?g/kg five times a week for 8 consecutive weeks. Thereafter the hypolipidemic effects were assessed by measuring total cholesterol, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol, and triglycerides, whereas the extent of oxidative stress was assayed by measuring thiobarbituric acid-reactive substances and enzymatic antioxidants such as superoxide dismutase, catalase, and reduced glutathione (GSH) in serum and PMF of liver and kidney. We assayed two liver biomarkers-alanine aminotransferase and aspartate aminotransferase-for safety of X. aethiopica at the dose given in this experiment. Cholesterol feeding resulted in a significant increase (P?相似文献   

大鼠烫伤后及补锌对血清、组织中锌、钙离子的影响

Objective To study the changes of zinc and calcium ion in serumand tissue of scalded rats with zinc supplementation. Methods 80 SD rats were randomly divided into control group before scald and N,W,H groups,the rats of N,W,H groups were exposed to dorsal scald injuries of deep skin thickness covering 15% of the total body surface areaa and then were fed on diets containing zinc 40 μg/g in N,W groups and 80 μg/g in H group,a ointment containing zinc 761.1 μg/g was applied on scalded skin in W group at the same time.Zinc and calcium ions concentration in serum,liver,bone,scalded skin were measured on 1、3、7day after scald respectively. Results 1 The serum Zn2+ levels in N,W groups were lower than control before scald (0.66 μg/ml),but it increased obviously in H group (up to 1.06 μg/ml on dl after scald).2. The liver Zn2+ showed increasing tendencies in all groups,It reached 41.7 μg/g on 1 day scald from 22.5 μg/g on before scald in H group and was 1.75 times as much as N group(P<0.01).the contents of calcium in liver increased to 31.7 mg/g from 26.1 mg/g in N,W groups and declined in H group comparing with control.3 The Zn2+ levels in bone showed degression tendencies in all groups from 1 to 7 day after scald,The concentration of bone Zn2+ was from 68.9 μg/g to 41.5 μg/g in N group,which was less 16.7 μg/g than that of H group(P<0.01).Ca2+:level in bone was 73.3mg/g before scald,It was 50.2mg/g in N group on 7 day and less 15.7mg/g comparing with H group(P<0.05)4.the Zn2+ content of scalded skin declined in N,Wgroup,however,the Zn2+ content increased obviously in Hgroup on first day scald,these reached a peak value 34.4μg/g in W group on 7 day,it was 2.8 time as much as before scald.the Ca2+:contents of scald skin display large extent increase in all group,especially in N group,these were 3.0、22.6、66.2 times higher than before scald(0.08mg/g)on 1、3、7 d respectively (P<0.01),But the increase extent in W group was more less level than in N group. Conclusions The contents of Ca2+ were decrease in serum,bone,and increase in live and scalded skin,the cause maybe relate to Ca2+ abnormal distributing in body and calcium overload in cell.Supplement zinc by diet mainly make the Zn2+ levels in serum and liver increase and the Ca2+ contents drop.Supplement zinc by wound can increase Zn2+ content and reduce the Ca2+ level in skin.zinc may posses a role to mitigate calcium overload in cell.     

Modulatory effects of Gymnema montanum leaf extract on alloxan-induced oxidative stress in Wistar rats

OBJECTIVES: In light of evidence that some complications of diabetes mellitus may be caused or exacerbated by oxidative damage, we investigated the effect of Gymnema montanum leaf extract (GLEt) on tissue antioxidant defense systems in alloxan-induced diabetes in rats. METHODS: GLEt was administered orally at a doses of 50, 100, and 200 mg/kg of body weight for 30 d, after which liver and kidney tissues were assayed for the degree of lipid peroxidation by means of markers, reduced glutathione content and activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione-S-transferase. RESULTS: Treatment of diabetic rats with GLEt increased the antioxidant levels. Liver and kidney from diabetic animals exhibited disturbances in antioxidant defense when compared with normal rats. GLEt at a dose of 200 mg/kg of body weight exhibited a significant effect as compared with 50 and 100 mg/kg of body weight. These effects were compared with glibenclamide, a reference drug. CONCLUSIONS: It may be concluded that, in diabetes, liver and kidney tissues are more vulnerable to oxidative stress and show increased lipid peroxidation. The antioxidant responsiveness mediated by G. montanum may be anticipated to have biological significance in eliminating reactive free radicals that may otherwise affect normal cell functioning and provide a scientific rationale for the use of G. montanum as an antidiabetic plant.     

Fish oil-enriched nutritional supplement attenuates progression of the acute-phase response in weight-losing patients with advanced pancreatic cancer.

The presence of an acute-phase protein response (APPR) has been suggested to shorten survival and contribute to weight loss in patients with pancreatic cancer. Fatty acids derived from fish oil have been shown to alter proinflammatory cytokine production and acute-phase protein synthesis in vitro. The present study was designed to determine the effects of a fish oil-enriched nutritional supplement on the concentrations of a range of individual acute-phase proteins (APP) in patients with advanced pancreatic cancer. In a sequential series, 18 patients with pancreatic cancer received the supplement (providing 2 g eicosapentaenoic acid and 1 g docosahexaenoic acid/d) for 3 wk while another 18 received full supportive care alone. Six healthy subjects served as additional controls. Acute-phase proteins were measured before and after the 3-wk intervention period in cancer patients. At baseline, albumin, transferrin and pre-albumin were significantly reduced and fibrinogen, haptoglobin, alpha-1-acid glycoprotein, alpha-1-antitrypsin, ceruloplasmin and C-reactive protein (CRP) were significantly elevated in the cancer patients compared with healthy controls, reflecting their roles as negative and positive acute phase proteins, respectively. In the supplemented cancer group, the only significant change in APP concentrations over the 4-wk study period was an increase in transferrin. In the control cancer group there were further significant reductions in albumin, transferrin and pre-albumin, and a significant increase in CRP concentration. These results suggest that many positive and negative APP are altered in advanced pancreatic cancer. The APPR tends to progress in untreated patients but may be stabilized by the administration of a fish oil-enriched nutritional supplement. This may have implications for reducing wasting in such patients.     

缺锌大鼠烫伤后补锌对血清锌、组织锌、碱性磷酸酶与生长激素影响

目的观察缺锌大鼠烫伤后补锌对体内锌、含锌酶、激素的影响。     

Fenugreek (Trigonella foenum graecum) seed extract prevents ethanol-induced toxicity and apoptosis in Chang liver cells

The protective effect of a polyphenolic extract of fenugreek seeds (FPEt) against ethanol (EtOH)-induced toxicity was investigated in human Chang liver cells. Cells were incubated with either 30 mM EtOH alone or together in the presence of seed extract for 24 h. Assays were performed in treated cells to evaluate the ability of seeds to prevent the toxic effects of EtOH. EtOH treatment suppressed the growth of Chang liver cells and induced cytotoxicity, oxygen radical formation and mitochondrial dysfunction. Reduced glutathione (GSH) concentration was decreased significantly (P < 0.05) while oxidized glutathione (GSSG) concentration was significantly elevated in EtOH-treated cells as compared with normal cells. Incubation of FPEt along with EtOH significantly increased cell viability in a dose-dependent manner, caused a reduction in lactate dehydrogenase leakage and normalized GSH/GSSG ratio. The extract dose-dependently reduced thiobarbituric acid reactive substances formation. Apoptosis was observed in EtOH-treated cells while FPEt reduced apoptosis by decreasing the accumulation of sub-G1 phase cells. The cytoprotective effects of FPEt were comparable with those of a positive control silymarin, a known hepatoprotective agent. The findings suggest that the polyphenolic compounds of fenugreek seeds can be considered cytoprotective during EtOH-induced liver damage.     

Effects of grape seed extract supplementation on exercise-induced oxidative stress in rats

The aim of the present study was to investigate the effects of grape seed extract (GSE) supplementation on exercise performance and oxidative stress in acutely and chronically exercised rats. A total of sixty-four male rats were used in the study. Rats were divided into six groups: control, chronic exercise control, acute exercise control (AEC), GSE-supplemented control, GSE-supplemented chronic exercise and GSE-supplemented acute exercise groups. Chronic exercise consisted of treadmill running at 25 m/min, 45 min/d, 5 d a week for 6 weeks. Rats in the acute exercise groups were run on the treadmill at 30 m/min until exhaustion. GSE were given at 100 mg/kg of body weight with drinking water for 6 weeks. Plasma was separated from blood samples for the analysis of oxidative stress markers. There was no significant difference in time of exhaustion between the acute exercise groups. Plasma malondialdehyde (MDA) levels were higher in the acute exercise groups and lower in the chronic exercise groups. GSE supplementation decreased MDA levels. Xanthine oxidase and adenosine deaminase activities were higher in the AEC group compared to all the other groups. NO levels were increased with both chronic exercise and GSE supplementation. Superoxide dismutase and glutathione peroxidase activities were lower in the acute exercised groups and higher in the chronic exercised groups. GSE supplementation caused an increase in antioxidant enzyme activities. In conclusion, GSE supplementation prevents exercise-induced oxidative stress by preventing lipid peroxidation and increasing antioxidant enzyme activities.     

锌和维生素E对糖尿病大鼠内皮细胞保护作用

目的探讨锌(Zn)和维生素E(VE)对链脲佐菌素(STZ)诱导的糖尿病(DM)大鼠氧化应激及内皮细胞的保护作用。方法对STZ诱导的糖尿病大鼠模型，补充Zn和VE，6周后观察血糖、血清胰岛索、血清总抗氧化能力(T—AOC)、血清丙二醛(MDA)、血浆血栓素B2(TXB2)、6-酮-前列腺素F1α(6-k-PGF1α)和内皮素(ET)变化。结果Zn和VE可以降低血糖、MDA、TXB2和ET水平，同时提高血清胰岛素水平、T—AOC和血浆6-k—PGF1α水平。结论补充Zn和VE可以减轻糖尿病大鼠氧化应激，保护内皮细胞，影响血浆TXB2、6-k—PGF1α和ET水平。     

Plantago maxima leaves extract inhibits adipogenic action of a high-fat diet in female Wistar rats

Purpose

The primary objective of this study is to investigate the content of biologically active compounds producing an antioxidant effect in Plantago maxima and their influence on main mechanisms of dietary obesity development.

Methods

Biologically active compounds in P. maxima were tested using paper chromatography. In in vivo experiment, high-fat-fed Wistar rats obtained P. maxima water extract for 3 months. Morphometric parameters, weight gain, serum adipokines, and cytokines, as well as oxidative stress biomarkers in rats’ tissues were evaluated. Gut microflora was also examined.

Results

Plantago maxima leaves used in the experiment contained significant amount of flavonoids, iridoids, phenol carboxylic acids, and tannins and ascorbic acid. Our in vivo experiment data demonstrate that P. maxima water extract prevents excessive adiposity in a diet-induced model. P. maxima consumption reduced serum leptin (twofold), macrophage chemoattractant protein-1 (sevenfold), tumor-necrosis factor-α (25 %), and interleukine-6 (26 %) levels. P. maxima water extract decreased adipose tissue oxidative stress biomarkers in rats fed a high-fat diet. In addition, increased bacterial growth in the diet-induced obesity model was reversed by the P. maxima extract treatment.

Conclusion

Plantago maxima water extract possessed antiadipogenic, antidiabetic, antiinflammatory, antioxidant activity, and normalized gut microflora in a rat model of diet-induced excessive adiposity due to a high content of biologically active compounds.