中链脂肪酸对高脂肪饲料诱导的肥胖C57BL/6J小鼠脂肪组织中转录因子的影响

摘要

目的观察中链脂肪酸(medium chain fatty acid，MCFA)对高脂肪饲料诱导的肥胖C57BL/6J小鼠脂肪组织中转录因子的表达，探讨中链脂肪酸降低体重、体脂肪的可能机制。方法30只C57BL/6J肥胖小鼠按空腹体重随机分为两组，每组15只，分别给予含2%MCFA和长链脂肪酸(long chain fatty acid，LCFA)的高脂饲料喂养12周，测定小鼠体重、体长，取小鼠肝脏、肠系膜周围脂肪垫、附睾周围脂肪垫及肾周脂肪垫并称重。采用BCA法测定附睾周围脂肪组织(white adipose tissue，WAT)蛋白浓度，采用ELISA法测定小鼠WAT中肿瘤坏死因子(tumor necrosis factor-α，TNF-α)和过氧化物酶体增殖物激活受体-γ(peroxisome proliferators-activated receptor-γ，PPAR-γ)水平，采用Real-time PCR法检测WAT中PPAR-γ、甾醇调控元件结合蛋白-1(sterol regulatory element-binding protein-1，SREBP-1)和CCAAT/增强子结合蛋白(CCAAT enhancer binding protein-α，C/EBP-α)的mRNA表达。结果 MCFA饲料组肥胖小鼠体质量、体长、肝脏质量、肾周脂肪质量、附睾周脂肪质量以及WAT中TNF-α水平、SREBP-1和C/EBP-α的mRNA表达量均显著低于LCFA饲料组(P＜0.05)。PPAR-γ水平及其mRNA表达量，两组之间无统计学差异(P＞0.05)。结论 MCFA可能通过下调脂肪组织中TNF-α、SREBP-1及C/EBP-α水平和mRNA表达，抑制脂肪细胞分化。%Objective To study the possible mechanism of medium chain fatty acid (MCFA) in reducing body weight and body fat mass by observing the effect of MCFA on expression of transcription factor mRNA in adipose tissue of obese mice. Methods Thirty C57BL/6J obese mice were randomly divided into MCFA group and long chain fatty acid (LCFA) group (15 in each group) according to their fasting body weight. Twelve weeks after they were fed with high fat diet containing 2%MCFA or LCFA, their body, liver, and mesenteric, epididymal, perirenal fat pads were weighed and their body heights were measured. Protein, peroxisome proliferators-activated receptor-γ(PPAR-γ) and tumor necrosis factor-α(TNF-α) levels in white adipose tissue (WAT) were measured by BCA and ELISA, respectively. Expressions of PPAR-γ, sterol regulatory element-binding protein-1(SREBP-1) and CCAAT enhancer binding protein-α(C/EBP-α) mRNA in WAT were detected by RT-PCR. Results The body, liver, and mesenteric, epididymal, perirenal fat pads were significantly lighter whereas the expression levels of TNF-α, SREBP-1 and C/EBP-αmRNA in WAT and the body height were significantly lower in the MCFA group than in LCFA group (P < 0.05). No significant difference was found in PPAR-γmRNA expression level between the two groups (P>0.05). Conclusion MCFA can inhibit the differentiation of adipocytes by down-regulating the expression levels of TNF-α, SREBP-1 and C/EBP-αmRNA in adipose tissue.