Effects Of Different Edible Oils Intake On Livsr And Blood Fatty Acid Profile And Lipid Metabolism In Mice

Hydrogenated soybean oil would get trans-Octadecenoic acid,elaidic acid mainly,during the industrial hydrogenation process.Yak butter is the extraction of yak milk,containing trans fatty acids,trans-11-Octadecenoic acid mostly.hydrogenated by microorganisms in ruminant rumen.Olive oil is obtained by direct squeeze of olive fruit,which mainly contains oleic acid.Taking soybean oil as control,hydrogenated soybean oil,yak butter and olive oil were used to investigate trans fatty acids' effect on fatty acid profile in mice liver and blood and on lipid metabolism,also its mechanism was determined.In this study,male C57-BL mice were used as the animal model,3-week(weaning)mice were divided into four groups randomly,and setting pressing soybean oil group as control.Other groups were freely fed with diets supplemented with olive oil,hydrogenated soybean oil or yak butter respectively.Mice were raised from 3-week-old to 4,5,6 and 8-week-old.The fatty acid profile in mice liver and blood were measured by GS-MS.And the differences of fatty acid profile between each group was analyzed by area normalization method.In liver's fatty acids profile,compared with soybean oil group,elaidic acid was higher in hydrogenated soybean oil group in 4,5,6 and 8-week-old mice(p<0.01).Meaningwhile,there were significant increase in vaccenic acid in both hydrogenated soybean oil group and yak butter group(p<0.01)and there was no significant difference between the rest of the group in the content of elaidic acid.There were slight differences among four groups in mainly content of polyunsaturated fatty acids during the process of oil intake and growth.However,when mice grow to 8-week-old,there were no significant differences in linoleic acid,linolenic acid,arachidonic acid and DHA.And there were no significant change in main fatty acid content in plasma and red blood cells among four groups.Hematoxylin and eosin staining was used to investigate the effect of edible oil intake on the morphology of mice liver.It was found that there were mild liver cell edema in both hydrogenated soybean oil group and yak butter group in 6-week-old and 8-week-old,with no obvious steatosis and necrosis in hepatocyte.And no obvious pathological changes were founded in mice liver of soybean oil group and oliver oil group.With further application of enzyme analysis to determine the content of cholesterol and triglyceride in mice liver and plasma,total cholesterol and triglyceride levels in mice liver of hydrogenated soybean oil group and yak butter group were significantly higher than that of control group(soybean oil group)(p<0.05),and hydrogenated soybean oil group is higher than yak butter group.However,there was no significant difference between oliver oil group and control in total cholesterol and triglyceride levels.And there were no significant difference among four groups in plasma cholesterol and triglyceride levels.Meanwhile,four groups of mice plasma alanine transaminase(ALT)and aspartate aminotransferase(AST)were determined.And there were no significant difference in plasma among four groups,suggesting intake of edible oil didn't induce the release of ALT and AST resulting from hepatocyte damage,which were consistent with the results of histological staining.With further application of Real time fluorescence quantitative PCR,the expression of PPAR alpha and ppar-gamma mRNA was detected.It was found that intake of hydrogenated soybean oil and yak butter would significantly improve the experission of PPAR-? mRNA(p<0.05),while there was no significant change in PPAR-y mRNA in oliver oil group.No significant change in PPAR-a mRNA among four groups.Meanwhile,Western Blot was used to detect PPAR-y protein level in mice liver.And there were significant increases in hydrogenated soybean oil group and yak butter group,indicating that the effect of hydrogenated soybean oil and yak butter on lipid metabolism may have some relevance with the experission of PPAR-? level.In conclusion,our results indicated that hydrogenated soybean oil and yak butter could significantly increase the content of trans fatty acids in mice liver,while appearing mild liver cell edema in mice liver,and remarkly increase cholesterol and triglycerides in mice liver.Besides,intake of hydrogenated soybean oil or yak butter could significantly increase experission of PPAR-? mRNA and protein,which suggested the effect of hydrogenated soybean oil and yak butter on lipid metabolism may have some relevance with the experission of PPAR-? level.