Abstract: Objective To investigate the effect of exogenous short-chain fatty acids (SCFAs) on fat metabolism in high-fat-diet induced obese mice. Methods Totally 40 male C57BL/6J mice aged three to four weeks were divided into four groups, and were fed with the normal-fat diet,high-fat diet,high-fat diet with propionate or butyrate for 4 months, respectively.At the end of the experiments, the blood, epididymal and subscapular fat and the liver were collected.Plasma triglyceride (TG) and total cholesterol (TCH) were measured, and hepatic and adipose tissue morphology were examined.Meanwhile, the mRNA expressions of fat metabolism associated genes were assayed by RT-PCR, including the adipose triglyceride lipase (atgl), hormone-sensitive lipase (hsl), acyl CoA:diacylgycerol acyltransferase 2 (dgat2), carnitine palmitoyltransferase (cpt) and uncoupling protein-1 (ucp1). Results Compared with the normal diet group, the body weight, plasma concentrations of TG and TCH, and fat accumulation in the liver significantly increased in the high-fat diet group (P<0.05). Supplementation of propionate or butyrate to the high-fat diet inhibited the increase in body weight and lipid droplet accumulation in the liver, and reduced plasma TG and TCH levels (P<0.05).The RT-PCR analysis showed that the mRNA expressions of atgl, hsl, and cpt1c in both the epididymal fat and liver in high-fat diet group significantly decreased compared with the normal diet group, while the dgat2 expression significantly increased (P<0.05). Supplementation of propionate or butyrate to the high-fat diet increased the mRNA expressions of atgl, hsl, and cpt1c, and reduced the dgat2 expression in the epididymal fat and liver (P<0.05).However, the expression of these genes in the subscapular fat was not affected by dietary propionate or butyrate supplementation (P>0.05). Conclusion Dietary supplementation of propionate and butyrate might inhibit the body weight gain in high-fat-diet induced obese mice by promoting TG lipolysis and oxidation.

Key words: propionate, butyrate, obesity, mouse, fat metabolism

摘要： 目的 探讨外源性短链脂肪酸对高脂诱导的肥胖小鼠脂肪代谢的影响。方法 将40只3~4周龄C57BL/6J雄性小鼠分成4组,分别给予正常饲料、高脂饲料以及分别添加丙酸和丁酸的高脂饲料喂养4个月。喂养过程结束后,心脏采血,取性腺周围脂肪、肩胛骨下脂肪和肝脏。检测血浆甘油三酯(TG)、总胆固醇(TCH)等浓度,观察脂肪和肝脏组织细胞形态变化,同时检测甘油三酯脂肪酶(atgl)、激素敏感脂肪酶(hsl)、二酯酰甘油酰基转移酶2(dgat2)、肉碱脂酰转移酶(cpt)及解偶联蛋白1(ucp1)等基因mRNA表达水平。结果 与正常饲料喂养组相比,高脂饲料组小鼠体重、血浆TG和TCH水平、肝脏脂肪聚集均显著增加(P<0.05);而高脂饲料中添加丙酸和丁酸则抑制了小鼠体重的增加和肝脏脂滴聚集,同时降低了血浆TG和TCH水平(P<0.05)。脂肪代谢相关基因表达检测显示,与正常饲料组小鼠相比,高脂饲料组小鼠性腺周围脂肪组织和肝脏中atgl、hsl、cpt1c基因mRNA的表达量均显著性降低,而dgat2基因mRNA的表达量明显升高(P<0.05);而高脂饲料中添加丙酸和丁酸提升了性腺周围脂肪组织和肝脏中agtl、hsl、cpt1c基因mRNA的表达,而抑制了dgat2的表达(P<0.05)。肩胛骨下脂肪中上述基因的表达几乎未受到饲料丙酸和丁酸添加的影响(P>0.05)。结论 丙酸和丁酸可能通过促进脂肪分解和氧化对高脂饲料诱导肥胖小鼠的体重增加发挥抑制作用。

关键词: 丙酸, 丁酸, 肥胖, 小鼠, 脂肪代谢