An Experimental Study On The Effect Of Cholecalciterol Cholesterol Emulsion On Lipid Accumulation In The Liver Of Mice

Background and purpose:Vitamin D is a fat-soluble vitamin which related to human health closely.Now,there is a growing awareness of the link between vitamin D deficiency and liver disease.Previous clinical studies have focused on the effect of vitamin D on chronic liver disease,but the effect of vitamin D on liver lipid metabolism has rarely been reported.The purpose of this study was to investigate the effect of Vitamin D on liver related indexes and liver lipid metabolism related enzymes.Providing a new perspective for further understanding of hepatic lipid deposition.Methods:In order to study the effect of Vitamin D on hepatic lipid deposition in mice,36 health male SPF grade ICR mice were randomly divided into 6 groups in this study,including 3 groups of normal diet feeding:control group,Vitamin D treat group,1α（OH）ase^-/-group.Three groups were fed high-fat group,high-fat+vitamin D,1α（OH）ase^-/-+high-fat.The aqueous solution of cholecalciterol cholesterol emulsion emulsion was 20μ+200ml,which was stored away from light.After 8 weeks of continuous feeding,the mice in each group were weighted and sacrificed.Fresh liver tissue was collected,thewet weight of liver was measured,and the liver coefficient of mice was calculated.The relative contents of triglyceride（TG）,cholesterol（TC）,and glucose（GLU）in liver tissuesof each group were determined;HEstaining method was used to detect the pathological changes of mice liver;Oil red O staining method was used to detect the hepatic lipid deposition in the liver tissues of mice in each group;Protein expression levels of PPARγ,CD36 and MTTP were detected by Western blot;mRNA expression of PPARγ,CD36 and MTTP in liver tissues was detected by RT-pcr.Results:1.Under normal diet compared with CON group,the liver coefficient of group CD was significantly higher,the difference was statistically significant.and the of group CD was significantly lower,the difference was statistically significant..Under the condition of high-fat diet,the liver coefficient of group HF was no different from that of group FD,the liver coefficient of the FD group was significantly higher than that of KOF group,the difference was statistically significant.2.Relative contents of TG,TC and GLU in liver tissues of mice were determined.the relative contents of TG,TC and GLU in liver tissues of group CD were higher than those of CON group under normal diet,the difference was statistically significant.The relative contents of TG,TC and GLU in the liver of mice in the KO group were significantly lower than those in the CON group,the difference was statistically significant.Under the condition of high-fat diet,the relative contents of TG,TC and GLU in the liver tissues of mice in the HF group were no different from in the FD group.and the relative contents of TG,TC and GLU in the liver tissues of mice in the KOF group were all lower than those in the HF group,the difference was statistically significant.Among which the relative contents of HF group were significantly higher than those in the KOF group,the difference was statistically significant.3.HE staining showed that hepatocytes in the CON group were normal in size and morphology,and small round vacuoles were observed in the liver tissue of CD group.No round open vacuoles were observed in the liver tissue of the KO group,and no significant changes were observed compared with the CON group,in the high-fat diet condition,HF and FD groups there were obvious round vacuolarsteatosis and balloon degeneration in the hepatocytes of mice in the KOF group,and no round vacuole was observed in the liver tissue of mice in the KOF group.4.Liver tissue oil red O staining showed that under normal diet.no round lipid drops were observed in CON group,smaller round lipid drops were observed in CD group,and no round lipid drops were observed in KO group.Under the condition of high-fat diet,large number of round fat drops could be observed in both group HF and group FD,but no circular fat drops could be observed in the liver tissues of mice in the KOF group.5.The expression levels of total PPARγprotein and mRNA in mice liver tissues under normal diet were detected,the expression levels of total PPARγprotein and mRNA in group CD were up-regulated compared with group CON,the difference was statistically significant.The expression of total PPRAγprotein and mRNA in KO group was down-regulated compared with group CON.Under the condition of high-fat diet,the expression levels of total PPRAγprotein and mRNA in mouse liver tissues were not statistically significant different from those in the HF and FD group,while the total PPRAγprotein and mRNA in the KOF group were down-regulated compared with the HF group.6.Expression levels of CD36 protein and mRNA were detected in liver tissues fed with normal diet.expression levels of CD36 protein and mRNA in group CD were up-regulated compared with group CON,the difference was statistically significant.And group KO were down-regulated compared with CON,the difference was statistically significant.Under the condition of high-fat diet,the expression levels of CD36 protein and mRNA in the liver tissues of mice in the HF group were not statistically significant different from the FD group,and the expression levels of CD36 protein and mRNA in the KOF group were lower than those in the HF group,the difference was statistically significant.7.the expression levels of MTTP protein and mRNA in mouse liver tissues were detected.under normal diet,the expression levels of MTTP protein and mRNA in group CD were higher than those in group CON,and the differences were not statistically significant.The expression levels of MTTP protein and mRNA in KO group were down-regulatedcompared with CON group,and the difference was not statistically significant,FD mice on high-fat diet.The expression levels of MTTP protein and mRNA in liver tissues were not different from those in group HF,and the MTTP protein and mRNA expression levels in group HF were higher than those in group KOF,but the difference were not statistically significant.Conclusions:1.VD increased the fatty acid entering the liver of mice and caused the deposition of hepatic lipid.2.VD promotes the expression of CD36,increases the fatty acids entering liver cells,and promotes the synthesis of liver lipids.3.During the lipid deposition in mouse liver induced by VD,the increase of free fatty acids entering liver cells by peripheral uptake maybe partly attributed to the up-regulation of PPARγby VD.