RESUMO
Objective This study investigated high fat diet influence on the changes of vitamin D receptor (VDR) expression and endothelial nitric oxide synthase (eNOS) in apolipoprotein E-deficient(apoE-/-) mice.MethodsApoE-/- mice and C57BLP6J mice were divide into two groups (normal control and high fat diet),high fat diet group were feed high fat feedstuff.Plasma 25-(OH)D levels were determined by competitive protein binding radioimmunity,VDR expression were determined by immunofluorescence and reverse transcription-polymerase chain reaction.The levels of NO and eNOS were determined by nitrate reductase.ResultsCompared with normal control group,high fat diet caused more severe dam-age of atherosclerosis in wild type mice and apoE-/- mice.In apoE-/- mice,the levels of plasma 25-(OH)D were significantly decreased [(26.44±1.28) ng/mL,(22.68±2.07)ng/mL,(17.46±2.22)ng/mL,(15.88±0.97)ng/mL,P＜0.01],the expression of VDR protein and mRNA were significantly increased[VDR :0.244±0.088,0.346±0.132,0.547±0.128,0.768±0.162;VDRmRNA:0.228±0.083,0.375±0.103,0.451±0.117,0.597±0.131,P＜0.01],and the levels of NO and eNOS were significantly increased[NO:(39.74±4.81)μmol/L,(48.1±5.24 )μmol/L,(67.34±6.14 )μmol/L,(86.74±8.05)μmol/L;eNOS:(8.6±0.77 )U/L,(12.28±1.42)U/L,(15.96±0.92)U/L,(18.68±1.15)U/L,P＜0.01].These changes were more significantly in high fat diet group(P＜0.01).ConclusionsThere were abnormalities of plasma 25-(OH)D level,VDR expression and the level of NO and eNOS in apoE-/- mice.These changes were more significantly in high fat diet group.
RESUMO
Objective To explore the effect of vitamin D receptor (VDR) in intestinal tumor development and the relationship between VDR and β-catenin signaling pathway. Methods The interaction of vitamin D receptor and β-catenin were detected by co-immunoprecipitation assay after human colonic carcinoma cells SW480 were treated with vitamin D in vitro for 4 hours. The expression of E-cadherin protein was detected by Western blot after treated for 24 hours. To compare APCmin/+VDR-/- and APCmin/+ mice in vivo, the expression of VDR,β-catenin and BrdU proteins in intestinal tumor were determined by immunohistochemistry. The expression of β-catenin protein in tumor and adjacency intestinal was further determined by Western blot. Results After SW480 cells were treated with vitamin D, vitamin D receptor and β-catenin protein showed binding, the expression of E-cadherin protein further increased (Gray value the control group 145.57±4.21,Gray value of the experimental group 109.35±3.56,t＝32.63,P＜0.05). Immunostaining and Western blot detection（Gray value 166.47±2.36） showed a marked increase of β-catenin level(Gray value 140.51±2.57) in APCmin/+VDR-/- tumor compared to APCmin/+ tumor(145.41±3.62,182.35±3.24,t＝2.65,4.36,P＜0.05). Conclusions The role of vitamin D suppressing intestinal tumor may be achieved through VDR affectingβ-catenin signaling pathway.