植物甾醇酯对高脂饮食大鼠结肠内容物短链脂肪酸的影响

目的:研究植物甾醇酯(phytosterol ester,PSE)对高脂饮食大鼠结肠内容物短链脂肪酸的影响。方法:将30只6周龄雄性SD大鼠随机分为四组,其中正常对照组饲喂普通饲料,高脂组饲喂高脂饲料,PSE干预组分别灌胃低(0.05 g/100 g BW·d)、高剂量PSE (0.10 g/100 g BW·d) PSE强化牛奶;连续干预13周后,处死动物取结肠内容物,利用气相色谱法测定其SCFAs的含量。结果:与正常对照组相比,高脂饮食使大鼠结肠内容物中总SCFAs含量增加33.63%,其中丙酸含量显著升高(126.07%)(p<0.05),乙酸(26.05%)和异戊酸(42.11%)含量具有升高趋势(p>0.05),丁酸(33.21%)和戊酸(23.92%)含量则表现为降低趋势(p>0.05);而PSE干预可抑制高脂饮食所致大鼠结肠内容物中SCFAs水平的升高,其中低剂量PSE可显著降低丙酸(51.52%)、丁酸(59.59%)、异戊酸(60.66%)和戊酸(72.07%)的含量(p<0.05);高剂量PSE干预可降低丁酸(29.48%)的含量(p>0.05),并显著降低乙酸(48.64%)、丙酸(58.39%)、戊酸(69.12%)和异戊酸(58.59%)的含量(p<0.05)。结论:高脂饮食会引起大鼠结肠中SCFAs水平的升高,而PSE可能通过降低结肠内容物SCFAs的含量来调节大鼠肠道内环境。     

Metabolic response of soy pinitol on lipid‐lowering,antioxidant and hepatoprotective action in hamsters fed‐high fat and high cholesterol diet

This study was performed to investigate the lipid‐lowering, antioxidant, and hepato‐protective effects of pinitol in dose‐dependent manners in hamsters fed‐high fat and high cholesterol (HFHC) diet. Pinitol supplementation (0.05%, P‐I and 0.1% pinitol, P‐II) with an HFHC diet (10% coconut oil plus 0.2% cholesterol) for 10 wks significantly lowered the white adipose tissue weights, hepatic lipid droplets, plasma glucose, total‐cholesterol, nonHDL‐cholesterol, total‐cholesterol/HDL‐cholesterol ratio, and hepatic lipid levels. Whereas it significantly increased the brown adipose tissue weight, plasma HDL‐cholesterol, apolipoprotein A‐I (apo A‐I) concentrations, paraoxonase (PON) activity, and/or mRNA expression, compared to the HFHC control group. Plasma insulin and adiponectin levels were significantly lower and higher, respectively, in both P‐I and P‐II groups than the HFHC control group. Dietary pinitol significantly inhibited hepatic HMG‐CoA reductase, acyl‐CoA:cholesterol acyltransferase (ACAT), and cytochrome P4502E1 (CYP2E1) activities without altering their mRNA expressions compared to the control group. Pinitol significantly elevated the hepatic antioxidant enzyme activities, whereas it also significantly reduced the hepatic lipid peroxide and H₂O₂ production. Accordingly, these results indicate that both 0.05 and 0.1% pinitol supplementation may improve the lipid and antioxidant metabolism in HFHC diet‐fed hamsters. In particular, pinitol supplementation was very effective on the elevation of antiatherogenic factors, including plasma HDL‐cholesterol, apo A‐I, adiponectin, and PON.     

Consumption of barley β‐glucan ameliorates fatty liver and insulin resistance in mice fed a high‐fat diet

Consumption of a diet high in barley β‐glucan (BG) has been shown to prevent insulin resistance. To investigate the mechanism for the effects of barley BG, three groups of male 7‐wk‐old C57BL/6J mice were fed high‐fat diets containing 0, 2, or 4% of barley BG for 12 wk. The 2% BG and 4% BG groups had significantly lower body weights compared with the 0% BG group. The 4% BG group demonstrated improved glucose tolerance and lower levels of insulin‐resistance index and glucose‐dependent insulinotropic polypeptide. Consumption of the BG diet decreased hepatic lipid content. Mice on the BG diet also demonstrated decreased fatty acid synthase and increased cholesterol 7α‐hydroxylase gene expression levels. The BG diet promoted hepatic insulin signaling by decreasing serine phosphorylation of insulin receptor substrate 1 and activating Akt, and it decreased mRNA levels of glucose‐6‐phosphatase and phosphoenolpyruvate carboxykinase. In summary, consumption of BG reduced weight gain, decreased hepatic lipid accumulation, and improved insulin sensitivity in mice fed a high‐fat diet. Insulin signaling enhanced due to the expression changes of glucose and lipid metabolism genes by BG consumption. Consumption of barley BG could be an effective strategy for preventing obesity, insulin resistance, and the metabolic syndrome.