香榧籽油对高脂膳食SD大鼠脂质代谢的影响及机理Effect of Torreya grandis cv. Merrilii seed oil on lipid metabolism in SD rats fed with high fat diet

Abstract

为推进对香榧籽油生物功效的认知，以高脂膳食大鼠模型评估香榧籽油的降脂、抗氧化功效及其作用机理。将40只SD大鼠随机分为正常对照组（NF组）、2%香榧籽油正常组（NFO组）、高脂对照组（HF组）、2%香榧籽油高脂组（HFO组）。每周记录SD大鼠体重，分别在第4周和第7周检测血清中总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）、血糖（Glu）、超氧化物歧化酶（SOD）、丙二醛（MDA）、谷胱甘肽过氧化物酶（GSH-Px）、总抗氧化能力（T-AOC）、C反应蛋白（CRP）、白介素6（IL-6）、白介素4（IL-4）水平。在第7周处死大鼠，解剖取肝脏、十二指肠、脂肪组织，采用油红O、苏木精-伊红（HE）染色观察组织形态，并采用qRT-PCR检测肝脏脂质代谢相关基因的表达。结果表明：实验第4周，与NF组相比，香榧籽油能极显著降低SD大鼠体重（P<0.01），整个实验周期内HF、HFO组大鼠体重无显著差异；与NF组相比，NFO组大鼠血清TG、Glu、MDA水平显著下降（P<0.05），HDL-C水平显著提高（P<0.05）；与HF组相比，香榧籽油能显著降低大鼠血清TC、LDL-C和Glu水平（P<0.05），显著提高SOD、GSH-Px的活性和T-AOC（P<0.01，P<0.05）。实验第7周，与NF组相比，NFO组大鼠血清LDL-C水平极显著上升（P<0.01），TC、MDA水平显著下降（P<005）；与HF组相比，香榧籽油能显著升高大鼠血清TG、LDL-C、MDA、CRP、IL-4水平（P<0.05，P<001）；长期食用香榧籽油,大鼠肝脏、十二指肠组织中偶有炎性细胞浸润，脂肪组织细胞形态大小不均。NFO组大鼠肝脏AMPKα、SREBP-1c基因表达水平极显著高于NF组（P<0.01），HFO组大鼠肝脏FAS、ACC、AMPKα基因表达水平极显著低于HF组（P<0.01）。香榧籽油可能通过调节AMPKα/SREBP-1c信号通路实现调节大鼠血脂、提高抗氧化水平的生物功效。 To advance the understanding of the biological efficacy of Torreya grandis cv. Merrilii seed oil, a high-fat dietary rat model was developed to evaluate the lipid-lowering and antioxidant effects of Torreya grandis cv. Merrilii seed oil and its mechanism of action. Forty SD rats were randomly divided into normal fat group (NF group), 2% Torreya grandis cv. Merrilii seed oil group (NFO group), high fat group (HF group)，and high fat with 2% Torreya grandis cv. Merrilii seed oil group (HFO group). The body weight of SD rats was recorded every week. The levels of serum total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), blood glucose (Glu), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), C reaction protein(CRP), interleukin-6 (IL-6), and interleukin-4 (IL-4) were detected at the 4th and 7th week, respectively. At the 7th week, the rats were sacrificed, and the liver, intestine and adipose tissue were dissected and observed by oil red O and hematoxylin-eosin (HE) staining. In addition, the expression of liver lipid metabolism related genes was detected by qRT-PCR. The results showed that in the 4th week of the experiment, compared with NF group, Torreya grandis cv. Merrilii seed oil could significantly reduce the body weight (P<0.01) and the levels of serum TG, Glu and MDA(P<0.05), and markedly increase HDL-C level (P<0.05). There was no significant difference in body weight of rats in HF and HFO groups during the 4 weeks experiment. Compared with HF group, Torreya grandis cv. Merrilii seed oil could reduce the levels of TC, LDL-C and Glu(P<0.05), increase the activities of SOD, GSH-Px and T-AOC(P<0.01,P<0.05). In the 7th week of the experiment, compared with NF group, the serum LDL-C level of the NFO group increased significantly(P<0.01), and the TC and MDA levels decreased significantly (P<0.05); compared with HF group, the Torreya grandis cv. Merrilii seed oil could significantly increase the levels of TG, LDL-C, MDA, CRP, IL-4 (P<0.05,P<0.01); inflammatory cells occasionally infiltrated into the liver and intestine of rats fed with Torreya grandis cv. Merrilii seed oil for a long time, and the shape and size of adipocytes were uneven. The expression levels of AMPKα and SREBP-1c in the liver of rats in NFO group were higher than those in NF group（P<0.01），while the expression levels of FAS, ACC, AMPKα in HFO group were lower than thoes in HF group（P<0.01）. The Torreya grandis cv. Merrilii seed oil may regulate the AMPKα/SREBP-1c signaling pathway to achieve the biological effect of regulating blood lipid and improving antioxidant level in rats.

Keywords

• 香榧籽油；降血脂；脂质代谢；多不饱和脂肪酸
• torreya grandis cv. merrilii seed oil; hypolipidemic; lipid metabolism; polyunsaturated fatty acid