| Objective: The aim of this study was to investigate the mechanism of the lipid lowering of conjugated linoleic acid glycerides in rats by means of a high fat model, and to provide a theoretical basis for its effectiveness. And the establishment of conjugated linoleic acid glyceride glycerol ester, diglycerides and triglycerides by high performance liquid chromatography-evaporative light scattering detector(ELSD) detection and analysis method.Methods: 72 SD rats were randomly divided into 6 groups: normal control group, high-fat control group, fish oil control group, low conjugated linoleic acid glyceride group, middle conjugated linoleic acid glyceride group, and high conjugated linoleic acid glyceride group. Except for the normal control group were fed with normal diet, the other groups were fed with high fat diet. Three doses of CLAG(2g/kg, 4g/kg, 6g/kg) were given to the rats continuously for 6 weeks by intragastric administration. Then all the rats were sacrificed by anaesthesia. Comparison of changes in body weight among the groups, to observe the pathological changes of liver tissue, calculate Lee’s index and body fat ratio, detection of serum lipid levels, the composition of serum fatty acid and blood glucose, antioxidant levels. Established CLAG analysis method by HPLC-UV, HPLC-RI and HPLC-ELSD, with Zorbax silica gel column, hexane-isopropanol as the mobile phase, control the different ratio, in order to achieve the complete separation of CLA-MG, CLA-DG and CLA-TG.Results: From the third week, compared with the high fat control group, the body weight in CLAG groups was decreased, but there was no significant. Compared with normal control group and high fat control group, the body weight in middle and high CLAG groups were decreased significantly in the 5th and 6th week. HE staining showed that the steatosis in high CLAG group reduced significantly, a small amount of inflammatory cell infiltration. Compared with high fat control group, the body fat ratio and Lee’s index in CLAG groups decreased. Compared with high fat control group, TC、TG、and LDL-C in CLAG groups decreased significantly, HDL-C in CLAG groups increased significantly(p<0.05);Compared with normal control group and high fat control group, total saturated fatty acids and polyunsaturated fatty acid in middle and high CLAG groups increased significantly, while monounsaturated fatty acid in CLAG groups decreased significantly(p<0.05). Compared with high fat control group, SOD、GSH-PX activity in CLAG groups increased significantly, while MDA in high CLAG group decreased significantly(p<0.05). EstablishedHPLC-ELSD method for qualitative and quantitative detection of CLAG, in the 4.62min、7.78min、 13.80 min time periods, CLA-TG, CLA-DG and CLA-MG were separated successfully. The results showed that the content of CLA-TG was 79.8%, CLA-DG was 19.8%, CLA-MG was 0.89%. The relative standard deviation(RSD) was less than 2%, and the precision was good, the detection limits of the CLA-TG、CLA-DG、CLA-MG were 0.6mg/kg、2.0mg/kg、2.5mg/kg, respectively, the limits of quantification were 6.0mg/kg、12.0mg/kg、12.0mg/kg, respectively.Conclusion: Conjugated linoleic acid glyceride can improve the pathological injury of liver tissue of rats with high fat diet, blood lipid level, blood glucose and body weight decreased significantly, reducing lipid peroxide production and alleviating the disorder of lipid metabolism. Using Zorbax silica gel column, HPLC-ELSD detection method, by changing the flow matching ratio, can achieve a good separation of CLA-TG, CLA-DG and CLA-MG, the precision and reproducibility of the method was good. |
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