Effects Of Endogenous T10c12-CLA On Lipid Metabolism In Mouse Liver

T10c12-CLA is a hydrogenation product of rumen microorganisms,an isomer of conjugated linoleic acid（CLA）,originally found in the meat and milk of ruminants,and exists as a mixture in nature,animal body cannot be synthesized by itself.It has many positive effects such as reducing white fat deposition,promoting skeletal muscle growth,reducing milk fat synthesis,preventing cardiovascular disease,and anti-cancer.It has been licensed by the US FAD to be sold as a food additive.However,a large number of literatures have shown that t10c12-CLA has side effects such as causing hepatic steatosis and altering glucose homeostasis.The liver is a complex metabolic reaction center in animals and plays an important role in maintaining life.In order to analyze the effect of a single isomer t10c12-CLA on lipid metabolism in mouse liver,this study used a transgenic mouse model（pai transgenic mouse）that could synthesize t10c12-CLA by itself in the laboratory.The liver was studied as follows.1 The effect of endogenous t10c12-CLA on mouse liver phenotypeIn this study,on the basis of the pai transgenic mouse model constructed in the laboratory in the early stage,the offspring were bred.The offspring of the pai transgenic mice obtained by breeding were used as materials.Histological and other apparent indicators were detected.The results showed that:（1）The liver of transgenic（Rosapai/pai,Rosapai/wt）mice turned yellow and brittle in appearance,increased liver weight and increased liver body index.（2）The detection results of fatty acid components showed that the content of t10c12-CLA in the livers of Rosapai/pai mice and Rosapai/wt mice were 0.24%and 0.20%,respectively,which was significantly higher than that of WT mice.In addition,the fatty acid components such as C22:5,C22:6 and total n3 in the liver of Rosapai/pai and Rosapai/wt mice were decreased,and the ratio of n6/n3 was increased.（3）The staining results of paraffin tissue sections showed that,in both male and female mice,Rosapai/wt mice had a large number of lipid droplet vacuoles compared with WT mice;Rosapai/pai mice had fewer lipid droplet vacuoles,but hepatocytes The structure changes,the hepatic cord disappears,and the hepatocytes become larger.From this,it can be inferred that t10c12-CLA changes the normal fatty acid composition of the liver and causes the disorder of liver fat metabolism.2 Effects of endogenous t10c12-CLA on hepatic glucose and lipid metabolism in miceBased on the above experimental results,this part of the study successively tested the blood glucose level,glucose tolerance（GTT）,liver triglyceride（TG）,cholesterol（TC）,and genes related to the hepatic glucose and lipid metabolism pathway in mice.The results found that:（1）In male and female mice,the blood glucose values of Rosapai/pai and Rosapai/wt mice were not significantly different from those of WT mice（p>0.05）.（2）The results of glucose tolerance showed that in male mice,Rosapai/pai and Rosapai/wt mice decreased blood glucose levels at a lower rate than WT mice,and the area under the curve was higher than that in WT mice;in female mice,Rosapai/wt mice The speed and area under the curve of lowering blood glucose values in mice were always higher than those in WT mice,and the speed and area under the curve in Rosapai/pai mice were comparable to those in WT mice.（3）The triglyceride in the liver showed a decreasing trend in female mice,and there was no significant difference in male mice;the content of cholesterol did not change significantly in both male and female mice.（4）RT-qPCR results of genes related to hepatic glucose and lipid metabolism pathways showed that Ppary,Ucpl,Glut4,Atgl,Cpt1α,Mcad,Pepck and other related genes were significantly down-regulated,and Cgi58 and Igf1 genes were significantly down-regulated in Rosapai/pai mice raised.Conclusions:（1）Endogenous t10c12-CLA caused an increase in liver weight,altered the normal fatty acid composition of the liver,and caused hepatic steatosis in mice.（2）Endogenous t10c12-CLA caused the disorder of hepatic lipid metabolism,decreased the synthesis of TG in the liver of female mice,and decreased the expression of some genes related to glucose and lipid metabolism.（3）There are gender differences and genotype differences in the effect of endogenous t10c12-CLA on liver lipid metabolism.