Chen Guangyong, Han Yangdong, He Wang, Liang Feng
Department of Pathology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Department of Endocrinology, Xi'an No. 1 Hospital, Xi'an, Shaanxi 710002, P.R. China.
Int J Mol Med. 2016 Dec;38(6):1759-1767. doi: 10.3892/ijmm.2016.2772. Epub 2016 Oct 14.
In the present study, we evaluated the protective effects of amentoflavone (AMF) against high-fat (HF) diet-induced metabolic dysfunction and focused on the influence of AMF on adipogenic differentiation during 3T3-L1 adipocyte differentiation. For this purpose, male Wistar rats were fed a HF diet or a HF diet with AMF (10 or 50 mg/kg). We found that AMF protected against HF diet-induced metabolic dysfunction in a dose-dependent manner, as evidenced by a decrease in the fasting blood glucose levels, fasting insulin levels and the homeostatic model assessment-insulin resistance index (HOMA‑IR), as well as by a decrease in the glucose level, as shown by the intraperitoneal glucose tolerance test and intraperitoneal insulin tolerance test. Moreover, the results revealed that AMF significantly inhibited the increase in body weight, the weight of perirenal adipose tissues and the serum triglyceride (TG) content of the rats fed the HF diet in a dose-dependent manner. AMF also inhibited the accumulation of oil droplets in differentiated 3T3-L1 adipocytes in a concentration-dependent manner. The incubation of the cells with AMF for 0-8, 0-2, 2-4, or 4-8 days markedly inhibited adipogenesis. During the early phase of the adipocyte differentiation of 3T3-L1 cells, AMF decreased CCAAT/enhancer-binding protein (C/EBP) β expression in a concentration-dependent manner, leading to the inhibition of mitotic clonal expansion (MCE). Moreover, our results demonstrated that AMF significantly increased reactive oxygen species (ROS) generation in the cells and the antioxidant, N-acetylcysteine (NAC), markedly attenuated the inhibitory effects of AMF on adipogenesis. AMF also inhibited the expression of peroxisome proliferator-activated receptor γ (PPARγ) and C/EBPα and the expression of downstream targets in a concentration-dependent manner. The overexpression of PPARγ and C/EBPα (by transfection with respective overexpression plasmids) attentuated the inhibitory effects of AMF on the formation of oil droplets. The inhibitory effects of AMF on adipocyte differentiation may contribute to its protective effects against HF diet-induced metabolic dysfunction. Overall, the data in our study provide novel insight into the mechanisms responsible for the protective effects of AMF against HF diet-induced metabolic dysfunction and those for its inhibitory effect on adipocyte differentiation.
在本研究中，我们评估了穗花杉双黄酮（AMF）对高脂（HF）饮食诱导的代谢功能障碍的保护作用，并重点关注了AMF对3T3-L1脂肪细胞分化过程中脂肪生成分化的影响。为此，将雄性Wistar大鼠喂食高脂饮食或添加AMF（10或50 mg/kg）的高脂饮食。我们发现，AMF以剂量依赖性方式预防高脂饮食诱导的代谢功能障碍，这表现为空腹血糖水平、空腹胰岛素水平和稳态模型评估-胰岛素抵抗指数（HOMA-IR）降低，以及腹腔内葡萄糖耐量试验和腹腔内胰岛素耐量试验显示的血糖水平降低。此外，结果表明，AMF以剂量依赖性方式显著抑制喂食高脂饮食大鼠的体重增加、肾周脂肪组织重量和血清甘油三酯（TG）含量。AMF还以浓度依赖性方式抑制分化的3T3-L1脂肪细胞中油滴的积累。用AMF处理细胞0-8天、0-2天、2-4天或4-8天显著抑制脂肪生成。在3T3-L1细胞脂肪细胞分化的早期阶段，AMF以浓度依赖性方式降低CCAAT/增强子结合蛋白（C/EBP）β的表达，导致有丝分裂克隆扩增（MCE）受到抑制。此外，我们的结果表明，AMF显著增加细胞中的活性氧（ROS）生成，而抗氧化剂N-乙酰半胱氨酸（NAC）显著减弱AMF对脂肪生成的抑制作用。AMF还以浓度依赖性方式抑制过氧化物酶体增殖物激活受体γ（PPARγ）和C/EBPα的表达以及下游靶点的表达。PPARγ和C/EBPα的过表达（通过转染各自的过表达质粒）减弱了AMF对油滴形成的抑制作用。AMF对脂肪细胞分化的抑制作用可能有助于其对高脂饮食诱导的代谢功能障碍的保护作用。总体而言，我们研究中的数据为AMF对高脂饮食诱导的代谢功能障碍的保护作用及其对脂肪细胞分化的抑制作用的机制提供了新的见解。
