高脂饮食对大鼠肠道益生菌和肝脂肪含量的影响

EFFECTS OF HIGH FAT DIET ON GUT PROBIOTICS AND HEPATIC FAT IN RAT

目的研究高脂饮食诱导非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)模型大鼠肠道益生菌变化及其与肝脏脂肪含量的关系。方法雄性SD大鼠20只随机分为对照组(control,C)和高脂饮食组(high fat,HF),分别给与普通大鼠饲料和高脂饮食喂养12w。观察体重、血ALT(alanine aminotransferase)、血脂水平、肝脏病理变化和肝脏脂肪含量;采用荧光定量PCR方法检测大鼠肠道双歧杆菌和乳酸杆菌动态变化(每两二周一次)。结果从第4w至实验结束,髙脂喂养大鼠体重明显高于普通饲料喂养组大鼠(均P<0.05)。与对照组相比,高脂饮食喂养大鼠血ALT(C:58.9±18.6 IU/L vs HF:59.8±6.8 IU/L)无明显变化,而血浆甘油三酯(C:0.3±0.1mmol/L vs HF:0.7±0.3 mmol/L,P=0.03)和胆固醇(C:1.4±0.1 mmol/L vs HF:1.7±0.3 mmol/L,P=0.04)水平明显增高。肝脏病理显示高脂组大鼠肝脏可见较多空泡脂肪变性和脂肪滴,而对照组大鼠无明显异常。髙脂组大鼠每克肝脏内脂肪组织所占比例亦较对照组大鼠明显增高(C:0.04±0.01%vs HF:0.16±0.03%,P<0.01)。髙脂饮食喂养大鼠肠道乳酸杆菌自第10周开始明显低于对照组大鼠,而双歧杆菌则从第8w即明显降低。大鼠体重和肝脏脂肪含量呈明显正相关关系(r=0.656,P=0.021),而肝脏脂肪含量与乳酸杆菌(r=-0.811,P=0.001)和双歧杆菌含量(r=-0.879,P=0.000)呈明显负相关关系。结论高脂饮食可致大鼠肠道肠道乳酸和双歧杆菌明显降低,且该现象与肝脏脂肪含量密切相关。

Objective To evaluate the effects of high fat diet on gut probiotics and its relationship with hepatic fat in rat model.Method Twenty male Sprague-Dawley rats were randomized（n=10） into control（C,receiving standard rat chow） and high fat group（HF,receiving fat-rich diet） with free access to food and water.Body weight was recorded every week.Gut lactobacillus and bifidobacterium were determinated once every two weeks by fluorescent quantitative real-time PCR.After 12 w,serum alanine aminotransferase（ALT）,triglycerides（TG）,total cholesterol（TC）,hepatic total lipids content,and liver histology were also evaluated.Results Hig-fat diet led to markedly body weight increase from the fourth week to the end of the study（all P〈0.05）.Serum TC（C,1.4 0.1 mmol/L vs HF,1.7 0.3 mmol/L;P=0.04）,TG（C,0.3 0.1mmol/L vs HF,0.7 0.3 mmol/L;P=0.03）,and hepatic total lipids content（C,0.04 0.01% vs HF,0.16 0.03%;P〈0.01） were significantly higher in HF group than those in control group while serum ALT（C,58.9 18.6 IU/L vs HF,59.8 6.8 IU/L;P=0.89） was similar between the two groups.Gut bifidobacteria were obviously lower at week 8,and lactobacilli at week 10 in HF group than those in control group.Hepatic total lipids content was positively correlated（r=0.656,P=0.021） with body weight,but negatively with gut lactobacillus（r=-0.811,P=0.001）,and bifidobacterium（r=-0.879,P=0.000）.Conclusion High fat diet led to obvious decrease in gut lactobacillus and bifidobacterium,which may be partly account for hepatic fat accumulation.