短期生酮饮食对小鼠代谢的影响

Short-term effect of ketogenic diet on metabolism of mice

目的:探讨短期生酮饮食对小鼠能量代谢的影响。方法:将Balb/c小鼠随机分成2组,分别给予普通饮食或生酮饮食4 d,每天称量体重并检测血糖变化。在第4天,取血检测甘油三酯(TG)、总胆固醇(TC)、游离脂肪酸(FFA)、丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、β-羟丁酸(β-HB)水平;称量肝脏重量,测定肝脏中TG、胆固醇以及糖原含量;real-time PCR检测肝脏组织中代谢相关基因的表达水平;制作肝脏HE染色切片,显微镜下观察肝脏病理学改变。结果:短期生酮饮食使小鼠体重明显减轻,血糖明显下降,血TC、β-HB、FFA高于普通饮食小鼠。生酮饮食小鼠肝重/体重比增加,肝组织中的TG增多,糖原减少。real-time PCR显示生酮饮食组小鼠脂肪酸氧化、氧化磷酸化以及酮体生成相关基因增加。显微镜下可见生酮饮食小鼠肝脏脂质蓄积明显增加。结论:生酮饮食可快速促进小鼠脂肪酸氧化和酮体生成。与长期生酮饮食不同的是,短期生酮饮食引起血TC显著增加和脂质合成基因FAS表达增多,而对肝脏无明显损伤作用。

Objective：To investigate short-term effect of ketogenic diet on metabolism of mice. Methods：BALB/c mice were divided into two groups and placed on normal diet or ketogenic diet for 4 days. Body weight and blood glucose were monitored everyday. On the fourth day,the blood samples and livers were gathered and liver weight/body weight were calculated. Serum triglycerides（TG）,total cholesterol（TC）,free fatty acids（FFA）,alanine aminotransferase（ALT）,aspartate aminotransferase（AST）,and beta hydroxybutyric acid（β-HB）were tested. The content of TG,cholesterol and glycogen in liver were detected. The expression levels of genes related to metabolism in livers were detected by real-time PCR. Liver pathology was also examined by HE staining. Results：Short-term ketogenic diet significantly reduced blood glucose and body weight of mice. Liver weight/body weight of short-term ketogenic mice was higher than that of control mice. A four-day feeding of ketogenic diet resulted in increased TC and β-HB in blood.Meanwhile,more TG and less glycogen were detected in the liver. Real-time PCR demonstrated that hepatic genes involved in fatty acid oxidation,oxidative phosphorylation and ketogenesis were increased. Accumulation of lipid was observed in the liver of ketogenic mice under a microscope. Conclusion：Short-term ketogenic diet induced fatty acid oxidation and ketogenesis in mice. Different from long-term ketogenic mice,elevated blood cholesterol and FAS m RNA levels were observed in short-term ketogenic mice without obvious liver damage.