共轭亚油酸诱导脂肪细胞凋亡和脂肪合成相关基因的表达障碍

STUDY ON THE EXPRESSION OF GENES RELEVANT TO APOPTOSIS AND FAT SYNTHESIS IN ADIPOSE TISSUE INDUCED BY CONJUGATED LINOLEIC ACID

目的了解共轭亚油酸(conjugated linoleic acid,CLA)是否引起脂肪细胞凋亡和脂肪合成相关基因的表达障碍。方法 40只6 w龄雄性昆明小白鼠,随机分为对照组和CLA组。对照组饲喂含1.5%亚油酸(LA)饲料,CLA组饲喂含1.5%CLA饲料,13 d后收集附睾脂肪组织,利用荧光定量PCR的方法检测脂肪合成相关基因的表达;化学发光试剂盒检测Caspase3/7的活性。结果与对照组相比,饲喂CLA的小鼠脂肪组织重量减少了49%(P<0.001)、血脂升高(P<0.01)和胰岛素敏感性显著下降。在饲喂CLA的小鼠脂肪组织中,脂肪合成关键酶乙酰辅酶A羧化酶(ACC)、硬脂酰辅酶A去饱和酶(SCD)及其主要激活因子SREBP-1c以及脂蛋白酯酶(LPL)的mRNA水平都显著性地低于对照组小鼠(P<0.01),同时Caspase3/7的活性较对照组小鼠升高4.45倍(P<0.01)。结论食物添加CLA引起脂肪细胞凋亡和脂肪合成相关基因的表达障碍,提示脂肪组织的脂肪合成受阻和凋亡加剧可能是食物添加CLA导致动物脂肪组织减少的部分原因。

Objective To study learn whether conjugated linoleic acid （CLA） induced apoptosis and the expression impairment of genes relevant to fat synthesis in adipose tissues. Methods Forty male Kunming mice were divided into control and CLA group, and were fed the diet containing 1.5% linoleic acid （LA） and 1.5% CLA for 13 d respectively. In epididymal adipose tissues, the expression of genes related to fat synthesis was detected by real-time PCR and caspase3/7 activity was measured by chemiluminescence kit. Results Compared to the control group, CLA-fed mice showed 49% loss of fat mass （P〈0.001） , significant elevation of plasma triglyceride and decline of insulin sensitivity. The mRNA levels of acetyl coenzyme A carboxylase （ACC）, stearoyl-CoA desaturase （SCD）, their main activating factor SREBP-lc and lipoprotein lipase （LPL） were significantly decreased in adipose tissue of CLA-fed mice compared with the control. Caspase 3/7 activity was increased 4.45-fold （P 〈0.01）. Conclusion CLA treatment induced apoptosis and decreased expression of genes relevant to fat synthesis in adipose tissues. It suggests that impaired fat synthesis and facilitated apoptosis may partially contribute to the fat loss caused by dietary supplementation of CLA.