目的:研究大豆不溶性膳食纤维(Soybean insoluble dietary fiber,SIDF)对高脂饮食(High fat diet,HFD)诱导小鼠肥胖的预防作用及其机理。方法:将50只C57BL/6J小鼠随机分为正常饮食对照组(Normal diet,ND)、高脂饮食对照组(HFD)和大豆不溶性膳食纤维低(Low-dose soybean insoluble dietary fiber,LSIDF)(250 mg/kg BW/d)、中(Middle-dose soybean insoluble dietary fiber,MSIDF)(500 mg/kg BW/d)、高剂量组(High-dose soybean insoluble dietary fiber,HSIDF)(1 g/kg BW/d),ND组饲喂正常饲料,其余各组饲喂高脂饲料,连续喂养20周。实验结束后统计体质量、肝脏和脂肪湿质量,制作肝脏组织病理切片,测定血清及肝脏脂质水平,实时荧光定量聚合酶链式反应测定小鼠肝脏中脂代谢相关基因表达水平。结果:与HFD组比,SIDF各剂量组可显著减缓小鼠体重增加,降低其血清和肝脏中总胆固醇(Total cholesterol,TC)、甘油三酯(Triglyceride,TG)水平(P<0.05),并且HSIDF组效果优于LSIDF、MSIDF组;小鼠肝脏指数(P<0.05)和脂肪系数(P<0.001)显著降低,其中MSIDF和HSIDF组小鼠腹部脂肪(P<0.001)和肾周脂肪重量(P<0.001)显著减少;HSIDF组显著下调小鼠肝脏中脂肪酸合成酶(Fatty acid synthase,FAS)、二酰甘油酰基转移酶1(Diacylglycerol acyltransferase-1,DGAT1)、二酰甘油酰基转移酶2(Diacylglycerol acyltransferase-2,DGAT2)、硬脂酰辅酶A去饱和酶1(Stearyl-coenzyme A dehydrogenase-1,SCD1)基因表达水平(P<0.05),同时上调过氧化物酶体增殖物激活受体α(Peroxisome proliferators-activated receptor-α,PPARα)、肉毒碱棕榈酰基转移酶1a(Carnitine palmtoyl transferase-1a,CPT1a)基因表达水平(P<0.05)。结论:IDFS对HFD诱导小鼠肥胖具有预防作用,可能与减少脂质合成,加快脂肪酸氧化有关,其可作为一种潜在的膳食补充剂。
Objective:To study the preventive effect and mechanism of soybean insoluble dietary fiber(SIDF)on high fat diet(HFD)induced obesity in mice. Methods:Fifty C57BL/6J mice were randomly divided into normal diet control group(ND),high fat diet control group(HFD),and soybean insoluble dietary fiber low(LSIDF),middle(MSIDF)and high dose group(HSIDF). The ND group was fed with normal diet,while the other groups were fed with high fat diet for 20 weeks. After the experiment,the body weight,liver and fat wet mass were counted,liver tissue pathological sections were prepared,serum and liver lipid levels were measured,and real-time fluorescence quantitative polymerase chain reaction was used to determine lipid metabolism-related gene expression levels in mice liver. Results:Compared with the HFD group,the SIDF dose groups could significantly slow down the weight gain of mice,reduce their total cholesterol(TC),triglyceride(TG)levels in serum and liver(P<0.05),and the HSIDF group has better effects than LSIDF,MSIDF group. The liver index(P<0.05)and fat coefficient(P<0.001)of the mice were significantly reduced. The abdominal fat(P<0.001)and periprenal fat weight(P<0.001)of the MSIDF and HSIDF groups were significantly reduced. In addition,the HSIDF group significantly down-regulated the mRNA expression of fatty acid synthase(FAS),diacylglycerol acyltransferase-1(DGAT1),diacylglycerol acyltransferase-2(DGAT2)and stearoyl-CoA desaturase-1(SCD1)(P<0.05). At the same time,up-regulated the mRNA expression of peroxisome proliferator-activated receptor-α(PPARα),carnitine palmitoyl transferase-1a(CPT1a)(P<0.05). Conclusion:IDFS has a preventive effect on HFD-induced obesity in mice,which may be related to reducing lipid synthesis and accelerating fatty acid oxidation,and can be used as a potential dietary supplement.