| 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. |
