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

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 4 th and 7 th week, respectively. At the 7 th 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 4 th 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 7 th 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-1 c signaling pathway to achieve the biological effect of regulating blood lipid and improving antioxidant level in rats.