High-Fat diet enhances accumulation of hexachlorobenzene in rat dams and delays its transfer from rat dams to suckling pups through milk

Effect of diets on the distribution and transfer of hexachlorobenzene (HCB) from dams to fetuses and suckling pups was investigated. In pregnant rats, the amount of HCB accumulated in fat tissues of the high-fat diet group was higher than that of the control diet group (P < 0.05). The amounts of HCB in fetuses of the high-fat and control diet groups were estimated to be about 0.28 and 0.12% of the dam's total intake during pregnancy, respectively. In both groups, a large proportion of HCB in dams disappeared during lactation period and was transferred to their pups through the milk. In the pups of the high-fat diet group, the amount of HCB in stomach contents was lower immediately after birth and decreased slowly compared with that in the control diet group during lactation. These results showed that a high-fat diet reduced the speed of the transfer of HCB from the dams to their suckling pups through milk.     

Effects of green tea polyphenol (-)-epigallocatechin-3-gallate on newly developed high-fat/Western-style diet-induced obesity and metabolic syndrome in mice

The aim of this study was to investigate the effects of (-)-epigallocatechin-3-gallate (EGCG) on newly developed high-fat/Western-style diet-induced obesity and symptoms of metabolic syndrome. Male C57BL/6J mice were fed a high fat/Western-style (HFW; 60% energy as fat and lower levels of calcium, vitamin D(3), folic acid, choline bitartrate, and fiber) or HFW with EGCG (HFWE; HFW with 0.32% EGCG) diet for 17 wks. As a comparison, two other groups of mice fed a low-fat diet (LF; 10% energy as fat) and high-fat diet (HF; 60% energy as fat) were also included. The HFW group developed more body weight gain and severe symptoms of metabolic syndrome than the HF group. The EGCG treatment significantly reduced body weight gain associated with increased fecal lipids and decreased blood glucose and alanine aminotransferase (ALT) levels compared to those of the HFW group. Fatty liver incidence, liver damage, and liver triglyceride levels were also decreased by the EGCG treatment. Moreover, the EGCG treatment attenuated insulin resistance and levels of plasma cholesterol, monocyte chemoattractant protein-1 (MCP-1), C-reactive protein (CRP), interlukin-6 (IL-6), and granulocyte colony-stimulating factor (G-CSF). Our results demonstrate that the HFW diet produces more severe symptoms of metabolic syndrome than the HF diet and that the EGCG treatment can alleviate these symptoms and body fat accumulation. The beneficial effects of EGCG are associated with decreased lipid absorption and reduced levels of inflammatory cytokines.     

葡萄籽原花青素对肥胖大鼠肠粘膜的影响

为探究葡萄籽原花青素(GSP)对营养肥胖模型大鼠肠粘膜通透性的影响,本试验设置了正常、模型、低剂量、中剂量及高剂量5个处理组,其中正常组投喂普通饲料,灌胃3 mL蒸馏水;模型组和低、中、高剂量组选用32只高脂饲料诱导的肥胖大鼠,模型组灌胃蒸馏水,低、中、高剂量组分别灌胃75、162.5、250 mg·kg^-1BW·d^-1GSP,灌胃处理6周再禁食12 h后处死,经解剖后测定各处理组大鼠的生理生化相关指标。结果表明,高脂饲料造模成功率48.75%;与模型组相比,低、中、高剂量组大鼠D-乳酸、乳果糖/甘露醇排出率显著降低,回肠绒毛高度/隐窝深度、紧密连接蛋白Occludin和 ZO-1 表达量显著升高;高剂量组大鼠的回肠杯状细胞数显著升高。综上,葡萄籽原花青素可以改善肥胖应激导致的大鼠肠道粘膜屏障损伤,这在一定程度上揭示了葡萄籽原花青素减肥降脂的作用机理。     

芦笋对高脂饮食小鼠肠道内容物细菌多样性的影响

为探讨芦笋对高脂饮食小鼠肠道内容物细菌多样性的影响,设计动物试验,试验分成4组,其中,正常对照组饲喂基础饲料,高脂饮食组、高脂饮食芦笋组、高脂饮食降脂理肝汤组均喂食高脂饲料;每只小鼠每天灌胃2次,每次0.35 mL,正常组与高脂饮食组为蒸馏水,高脂饮食芦笋组为2.10 g·kg^-1芦笋液,高脂饮食降脂理肝汤组为1.19 g·kg^-1降脂理肝汤。试验结束后提取肠道内容物微生物总DNA,进行16S rDNA V4区基因组测序。结果表明,从操作分类单元(OTU)总数来看,正常对照组OTU总数有 1 264 种,高脂饮食组OUT总数为1 564 种,高脂饮食降脂理肝汤组和高脂饮食芦笋组OUT总数分别为 1 354 和1 654 种,表明芦笋液抑制、降脂理肝汤能促进肠道细菌OUT总数恢复至正常水平。样本群落(Alpha)多样性分析表明,高脂饮食芦笋组、高脂饮食降脂理肝汤组和正常对照组丰富度估计指数(Chao)、多样性指数(Shannon)、丰富度估计指数(ACE)及多样性指数(Simpson)均低于高脂饮食组,且高脂饮食芦笋组Shannon指数显著低于高脂饮食组。细菌门分类分析表明,高脂饮食芦笋组变形菌门(Proteobacteria)、放线菌门(Actinobacteria)相对丰度介于高脂饮食组与正常对照组之间,高脂饮食降脂理肝汤组厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)相对丰度介于高脂饮食组与正常对照组之间,蓝细菌(Cyanobacteria)相对丰度在各组间有差别,但差异不显著。本研究结果表明,芦笋通过改变肠道菌群结构达到了降脂的效果,为芦笋产品的进一步开发研究提供了理论依据。     

Amelioration of obesity and glucose intolerance in high-fat-fed C57BL/6 mice by anthocyanins and ursolic acid in Cornelian cherry (Cornus mas)

Much attention has been focused on food that may be beneficial in preventing diet-induced body fat accumulation and possibly reduce the risk of diabetes and heart disease. Cornelian cherries (Cornus mas) are used in the preparation of beverages in Europe and also to treat diabetes-related disorders in Asia. In this study, the most abundant bioactive compounds in C. mas fruits, the anthocyanins and ursolic acid, were purified, and their ability to ameliorate obesity and insulin resistance in C57BL/6 mice fed a high-fat diet was evaluated. Mice were initially fed a high-fat diet for 4 weeks and then switched to a high-fat diet containing anthocyanins (1 g/kg of high-fat diet) and ursolic acid (500 mg/kg of high-fat diet) for an additional 8 weeks. The high-fat diet induced glucose intolerance, and this was prevented by anthocyanins and ursolic acid. The anthocyanin-treated mice showed a 24% decrease in weight gain. These mice also showed decreased lipid accumulation in the liver, including a significant decrease in liver triacylglycerol concentration. Anthocyanin and ursolic acid treated mice exhibited extremely elevated insulin levels. Both treatments, however, showed preserved islet architecture and insulin staining. Overall, these data suggest that anthocyanins and ursolic acid purified from C. mas fruits have biological activities that improve certain metabolic parameters associated with diets high in saturated fats and obesity.     

Guar gum reduces trichloroethylene accumulation in the body by reducing TCE absorption and fat tissue mass.

Two studies were conducted regarding the effects of guar gum on accumulation and metabolism of trichloroethylene (TCE). In study 1, 6- and 14-weeks-old rats were given a single oral dose of 100 mg of trichloroethylene (TCE). Ten hours after administration of TCE, a marked positive correlation was noted between relative fat tissue weights and TCE distribution in fat tissues. Therefore, a small mass of fat tissue apparently limited TCE accumulation. In study 2, each of four groups of rats was fed one of four diets: cellulose-soybean oil, cellulose-docosahexaenoic acid (DHA), guar gum-soybean oil, or guar gum-DHA for 3 weeks and then all were given TCE as in study 1. The rate of decrease of TCE distributed in fat tissues of groups fed guar gum compared with corresponding groups fed cellulose was greater than the rate of decrease in relative weight of these tissues. TCE absorption by groups fed guar gum decreased 12% compared with TCE absorption of corresponding groups fed cellulose. Therefore, guar gum decreased TCE accumulation in the body by reducing TCE absorption and fat tissue mass.     

Lower weight gain and hepatic lipid content in hamsters fed high fat diets supplemented with white rice protein, brown rice protein, soy protein, and their hydrolysates

The physiological effects of the hydrolysates of white rice protein (WRP), brown rice protein (BRP), and soy protein (SP) hydrolyzed by the food grade enzyme, alcalase2.4 L, were compared to the original protein source. Male Syrian Golden hamsters were fed high-fat diets containing either 20% casein (control) or 20% extracted proteins or their hydrolysates as the protein source for 3 weeks. The brown rice protein hydrolysate (BRPH) diet group reduced weight gain 76% compared with the control. Animals fed the BRPH supplemented diet also had lower final body weight, liver weight, very low density lipoprotein cholesterol (VLDL-C), and liver cholesterol, and higher fecal fat and bile acid excretion than the control. Expression levels of hepatic genes for lipid oxidation, PPARα, ACOX1, and CPT1, were highest for hamsters fed the BRPH supplemented diet. Expression of CYP7A1, the gene regulating bile acid synthesis, was higher in all test groups. Expression of CYP51, a gene coding for an enzyme involved in cholesterol synthesis, was highest in the BRPH diet group. The results suggest that BRPH includes unique peptides that reduce weight gain and hepatic cholesterol synthesis.     

Improvement of obesity phenotype by Chinese sweet leaf tea (Rubus suavissimus) components in high-fat diet-induced obese rats

Drinking an herbal tea to lose weight is a well-liked concept. This study was designed to examine the possible improvement of obesity phenotype by a new tea represented by its purified components, gallic acid, ellagic acid, and rubusoside (GER). Male obese-prone SD rats were given low-fat diet, high-fat diet, or high-fat diet plus GER at the dose of 0.22 g/kg of body weight for 9 weeks. GER significantly reduced body weight gain by 22% compared to the high-fat diet control group with 48% less abdominal fat gain. Food intake was not affected. Blood glucose was lowered in the GER-treated group, whereas serum triglycerides and cholesterol were significantly reduced by 50%. This improved obesity phenotype may be associated with the attenuated expression of vascular endothelial growth factor in preadipocyte 3T3-L1 cells. Although other underlying, possibly multiple, mechanisms behind the improved phenotype are largely unknown, the observed improvement of multiple obesity-related parameters by the new tea warrants further investigations.     

Konjac glucomannan and inulin systematically modulate antioxidant defense in rats fed a high-fat fiber-free diet

The aim of this study was to investigate the effects of konjac glucomannan (KGM) and inulin on the balance between pro-oxidative status and antioxidative defense systems in the colon, liver, and plasma of rats fed a high-fat fiber-free diet. Male Sprague-Dawley rats (n = 8 animals per group) were fed a high-fat (25% corn oil, w/w) fiber-free diet or that supplemented with KGM or inulin fiber (5%, w/w) for 4 weeks. The index of pro-oxidative status, malondialdehyde (MDA), and blood lymphocyte DNA damage; the antioxidative defense, that is, antioxidant enzymes (glutathione peroxidase, superoxide dismutase, catalase) in the colonic mucosa and liver; and the plasma antioxidant levels were determined. The fermentation of fiber was shown in fecal short-chain fatty acids. Incorporation of KGM and inulin into the high-fat fiber-free diet beneficially reduced the MDA levels of the colon and liver and DNA damage in blood lymphocytes. On the other hand, both fibers enhanced the antioxidative defense systems by up-regulating the gene expressions of glutathione peroxidase and catalase in the colonic mucosa and of superoxide dismutase and catalase in the liver. Furthermore, KGM and inulin promoted antioxidative status in the blood by elevating the α-tocopherol level. KGM and inulin were well-fermented in rats and increased the concentration and daily excretion of fecal short-chain fatty acids, especially acetate and butyrate. These results suggest that in vivo utilization of KGM and inulin stimulated both local and systemic antioxidative defense systems in rats.     

Whole berries versus berry anthocyanins: interactions with dietary fat levels in the C57BL/6J mouse model of obesity

Male C57BL/6J mice received diets with either 10% of calories from fat (LF) or a high-fat diet [45% (HF45) or 60% (HF60) calories from fat] for 92 days (expt 1) or 70 days (expt 2). These were given with or without freeze-dried powders from whole blueberries (BB) or strawberries (SB) (expt 1) or purified anthocyanin extracts from BB or SB (expt 2). Body composition was determined utilizing Echo MRI. Berries added to the LF diet did not alter weight gain, final body weights, body fat, or protein (percent body weight) or diet (grams) or energy (kilocalories) intake. However, in both HF45- and HF60-fed mice, weight gain, final weights, body fat (percent), and epididymal fat weights increased and body protein decreased ( p < 0.01) compared to LF mice. In mice fed HF45 diet plus BB, body weight gains, body fat (percent of BW), and epididymal fat weights were significantly greater than those in the HF45-fed controls, whereas weights of mice fed SB HF were similar to those of HF controls. SB or BB feeding did not alter glucose tolerance, although glucose tolerance decreased with age and in HF45 versus LF mice. Baseline plasma glucose was lower in SB- versus HF45-fed mice. After 8 weeks, mice fed the HF60 diet plus purified anthocyanins from BB in the drinking water had lower body weight gains and body fat than the HF60-fed controls. Anthocyanins fed as the whole blueberry did not prevent and may have actually increased obesity. However, feeding purified anthocyanins from blueberries or strawberries reduced obesity.     

Effects of konjac glucomannan on putative risk factors for colon carcinogenesis in rats fed a high-fat diet

The aim of this study was to determine effects of konjac glucomannan (KGM) in a high fat corn oil diet on risk factors of colon carcinogenesis, that is, fecal β-glucuronidase, mucinase, and bile acids, and on preventive factors, that is, fecal microflora and cecal short-chain fatty acids (SCFAs). Sprague-Dawley rats (n = 8 animals per group) were fed a normal-fat fiber-free (5% corn oil, w/w) or high-fat (25% corn oil, w/w) diet containing no fiber, KGM (5%, w/w), or inulin (5%, w/w, as a prebiotic control) for 4 weeks. Results indicated that the high-fat fiber-free diet significantly elevated the fecal β-glucuronidase and mucinase activities and total bile acid concentration and decreased cecal SCFA contents, as compared with its normal-fat counterpart. The incorporation of KGM, as well as inulin, into the high-fat fiber-free diet beneficially reduced the fecal β-glucuronidase and mucinase activities and lithocholic acid (secondary bile acid) concentration. Although KGM elevated the daily fecal total bile acid excretion, the change was due to the primary, instead of the secondary, bile acids. In addition, KGM beneficially promoted the daily fecal excretion of bifidobacteria and lactobacilli and cecal SCFA contents, as compared with the high-fat fiber-free diet. Therefore, the present study suggests that KGM potentially attenuated the high fat-induced risk in colon carcinogenesis.     

Barley intake induces bile acid excretion by reduced expression of intestinal ASBT and NPC1L1 in C57BL/6J mice

To investigate the hypocholesterolemic mechanism of barley in vivo, six-week-old C57BL/6J mice were fed a high-fat diet (HFD) or high-fat diet containing barley (HFD-B) for seven weeks. Total and LDL cholesterol concentrations were significantly reduced in the HFD-B group while fecal cholesterol and bile acid was increased. Real-time PCR and immunoblot analysis revealed the induction of FXR expression, which in turn suppressed the expression of ASBT and NPC1L1 in the HFD-B group compared with the controls. In the liver, the expression of HMG-CoA reductase was significantly reduced while LDL receptor expression was unaltered in the HFD-B group compared with the controls. Our data suggest that the hypocholesterolemic effects of barley are primarily the result of reduced dietary cholesterol uptake and bile acid resorption. Reduced expression of intestinal ASBT and NPC1L1 may play a key role in the regulation of dietary cholesterol and bile acid metabolism in mice consuming a diet containing barley.     

Effect of chitosan, O-carboxymethyl chitosan, and N-[(2-hydroxy-3-N,N-dimethylhexadecyl ammonium)propyl] chitosan chloride on overweight and insulin resistance in a murine diet-induced obesity

Two water-soluble chitosan derivatives, O-carboxymethyl chitosan (O-CM-chitosan) and N-[(2-hydroxy-3-N,N-dimethylhexadecyl ammonium)propyl] chitosan chloride (N-CQ-chitosan), were prepared, and the therapeutic effects of chitosan, O-CM-chitosan, and N-CQ-chitosan on insulin resistance were simultaneously evaluated by rats fed on a high-fat diet. The parameters of high-fat diet-induced rats indicated that chitosan and its two derivatives not only have low cytotoxicity but can control overnutrition by fat and achieve insulin resistance therapy. However, the results in experiment in vivo showed that the therapeutic degree varied by the molecular weight and surface charge of chitosan, O-CM-chitosan, and N-CQ-chitosan. N-CQ-chitosan with a MW of 5 × 10(4) decreased body weight, the ratio of fat to body weight, triglyceride, fasting plasma glucose, fasting plasma insulin, free fatty acid, and leptin by 11, 17, 44, 46, 44, 87, and 64% and increased fecal lipid by 95%, respectively.     

Effects of Chinese and North American Wild Rice on Blood Lipids,Oxidative Stress,and Inflammation Factors in Hyperlipidemic Rats

The aim of the present study was to compare the effects of replacing processed rice and wheat starch with Chinese and North American wild rice as the chief source of dietary carbohydrates in rats fed high levels of saturated fat and cholesterol. The study consisted of five groups: low‐fat diet, high fat/cholesterol diet, city diet, North American wild rice diet, and Chinese wild rice diet. At the end of eight weeks of the diet regimen, the North American and Chinese wild rice diets suppressed the increase in serum triglyceride and total cholesterol but also decreased the high‐density lipoprotein cholesterol level. In addition, rats fed either the North American or Chinese wild rice diet suppressed the build‐up of oxidative stress by improving total antioxidant capacity, increasing superoxide dismutase activity, and reducing malondialdehyde concentration. In contrast, rats fed with the high fat/cholesterol diet and city diet had increased concentrations of high‐sensitivity C‐reactive protein (hs‐CRP) and tumor necrosis factor α (TNF‐α) compared with the low‐fat diet; rats fed with the Chinese wild rice diet had a significantly decreased serum hs‐CRP protein and TNF‐α concentration. Higher serum hs‐CRP levels were verified in the city diet group compared with North American wild rice diet group. These findings illustrate that both North American wild rice and Chinese wild rice are effective in suppressing hyperlipidemia, oxidative stress, and inflammation in rats even when the diet consumed is high in fat and cholesterol.     

Food matrix effects on bioactivity of broccoli-derived sulforaphane in liver and colon of F344 rats

Sulforaphane (SF) is considered to be the major anticarcinogenic component in broccoli. The effects of feeding rats purified SF (5 mmol/kg of diet), broccoli containing SF formed in situ during laboratory hydrolysis (broccoli-HP; 20% freeze-dried broccoli diet, 0.16 mmol of SF/kg of diet), and broccoli containing intact glucosinolates (broccoli-GS; 20% freeze-dried broccoli diet, 2.2 mmol of glucoraphanin/kg of diet) were compared. Rats (male F344 rats, five per group) were fed control (modified AIN-76 B-40), SF, broccoli-HP, or broccoli-GS for 5 days. In rats fed broccoli-GS, quinone reductase activities (QR) in the colon and liver were greater (4.5- and 1.4-fold over control, respectively) than in rats fed broccoli-HP (3.2- and 1.1-fold over control, respectively). Broccoli-GS and SF diets increased QR to the same extent, even though the broccoli-GS diet contained far less SF (as the unhydrolyzed glucosinolate, glucoraphanin) than the purified SF diet. In a second experiment, rats were fed one of six diets for 5 days: (1) control; (2) 20% broccoli-GS; (3) diet 2 + low SF (0.16 mmol/kg of diet); (4) diet 2 + high SF (5 mmol/kg of diet); (5) low SF (0.32 mmol/kg of diet); or (6) high SF (5.16 mmol/kg of diet). In both liver and colon, QR was increased most by high SF plus broccoli-GS; individually, high SF and broccoli-GS had similar effects, and adding the low-dose SF to broccoli-GS had either no effect or a negative effect. In both experiments, urinary SF-mercapturic acid correlated with QR activity, not with dietary intake. It was concluded that all diets were substantially more effective in the colon than in the liver and that broccoli-GS was more potent than SF or broccoli-HP.     

A black soybean seed coat extract prevents obesity and glucose intolerance by up-regulating uncoupling proteins and down-regulating inflammatory cytokines in high-fat diet-fed mice

Black soybean seed coat extract (BE) is a polyphenol-rich food material consisting of 9.2% cyanidin 3-glucoside, 6.2% catechins, 39.8% procyanidins, and others. This study demonstrated that BE ameliorated obesity and glucose intolerance by up-regulating uncoupling proteins (UCPs) and down-regulating inflammatory cytokines in C57BL/6 mice fed a control or high-fat diet containing BE for 14 weeks. BE suppressed fat accumulation in mesenteric adipose tissue, reduced the plasma glucose level, and enhanced insulin sensitivity in the high-fat diet-fed mice. The gene and protein expression levels of UCP-1 in brown adipose tissue and UCP-2 in white adipose tissue were up-regulated by BE. Moreover, the gene expression levels of major inflammatory cytokines, tumor necrosis factor-α and monocyte chemoattractant protein-1 were remarkably decreased by BE in white adipose tissue. BE is a beneficial food material for the prevention of obesity and diabetes by enhancing energy expenditure and suppressing inflammation.     

Muscadine Grape ( Vitis rotundifolia ) and Wine Phytochemicals Prevented Obesity-Associated Metabolic Complications in C57BL/6J Mice

The objective of this study was to determine the effects of muscadine grape or wine (cv. Noble) phytochemicals on obesity and associated metabolic complications. Muscadine grape or wine phytochemicals were extracted using Amberlite FPX66 resin. Male C57BL/6J mice were given a low-fat diet (LF, 10% kcal fat), high-fat diet (HF, 60% kcal fat), HF + 0.4% muscadine grape phytochemicals (HF+MGP), or HF + 0.4% muscadine wine phytochemicals (HF+MWP) for 15 weeks. At 7 weeks, mice fed HF+MGP had significantly decreased body weights by 12% compared to HF controls. Dietary MGP or MWP supplementation reduced plasma content of free fatty acids, triglycerides, and cholesterol in obese mice. Inflammation was alleviated, and activity of glutathione peroxidase was enhanced. Consumption of MGP or MWP improved insulin sensitivity and glucose control in mice. Thus, consumption of muscadine grape and wine phytochemicals in the diet may help to prevent obesity-related metabolic complications.     

Effect of dietary conjugated linoleic acid on lipid peroxidation and histological change in rat liver tissues

The effect of dietary conjugated linoleic acid (CLA) on hepatic lipid parameters in Sprague-Dawley rats was examined. When rats were fed a diet containing CLA at 0 (control), 1, or 2% of the weight of the amount of food given for 3 weeks, the liver weight exhibited a slight increase in the CLA-fed groups, although the difference was not significant. Lipid accumulation in the hepatocytes of CLA-fed rats was also demonstrated by electron microscopic observation. In addition, the liver thiobarbituric acid reactive substances levels were significantly higher in the 2 wt % CLA group than in the other two dietary groups, and the levels of phosphatidylcholine hydroperoxide were higher in CLA-fed groups when compared to that of the control group. On the other hand, the serum lipid peroxide levels were comparable among all three dietary groups. Levels of triglycerides in the white adipose tissue (WAT) and serum nonesterified fatty acid (NEFA) were reduced in a CLA-dose-dependent manner. CLA was shown to accumulate in the WAT much more than in the serum or liver. These results suggest that CLA accelerates the decomposition of storage lipids in WAT and the clearance of serum NEFA levels, resulting in lipid peroxidation and a morphological change in the liver.     

Micronutrient-enriched rapeseed oils improve the brain oxidant/antioxidant system in rats fed a high-fat diet

The main proposal of this study was to evaluate in vivo whether micronutrient-enriched rapeseed oils obtained using different crushing and refining procedures and characterized by different quantities and qualities of micronutrients (optimized oils) could have any beneficial effect on the antioxidant status of the brain. Sprague-Dawley rats were fed a high-fat diet for 4 weeks. The lipid source consisted of 20% optimized rapeseed oils with different quantities and qualities of micronutrients. The control group received traditional refined rapeseed oil. The experimental optimized oils decreased lipid peroxidation and increased endogenous antioxidant status in parallel with the enhancement of micronutrients. No alteration in acetylcholinesterase activity was induced by the high-fat diet in any experimental group. These results indicate that a regular intake of optimized rapeseed oils can prevent oxidative stress, providing evidence that optimized rapeseed oils could be a functional food with potentially important neuroprotective properties.     

Protective effect of supplementation of fish oil with high n-3 polyunsaturated fatty acids against oxidative stress-induced DNA damage of rat liver in vivo

The present study was undertaken to know the effect of supplementation of fish oil with high n-3 polyunsaturated fatty acids (PUFA) on oxidative stress-induced DNA damage of rat liver in vivo. Male Wistar rats were fed a diet containing fish oil or safflower oil with high n-6 PUFA at 50 g/kg of diet and an equal amount of vitamin E at 59 mg/kg of diet for 6 weeks. Livers of rats fed fish oil were rich in n-3 PUFA, whereas those of rats fed safflower oil were rich in n-6 PUFA. Ferric nitrilotriacetate was intraperitoneally injected to induce oxidative stress. The degree of lipid peroxidation of the liver was assessed by the levels of phospholipid hydroperoxides and thiobarbituric acid-reactive substances (TBARS), and the degree of oxidative DNA damage was assessed by comet type characterization in alkaline single-cell gel electrophoresis and 8-hydroxy-2'-deoxyguanosine levels. The levels of TBARS of the livers of the fish oil diet group increased to a greater extent than those of the safflower oil diet group, whereas the levels of the hydroperoxides of the livers of both diet groups increased to a similar extent. The vitamin E level of livers of the fish oil diet group was remarkably decreased. The degree of DNA damage of both diet groups was increased, but the increased level of the fish oil diet group was remarkably lower than that of the safflower oil diet group. The above results indicate that fish oil supplementation does not enhance but appears to protect against oxidative stress-induced DNA damage and suggest that lipid peroxidation does not enhance but lowers the DNA damage.