Effects Of Vitamin D On The Expression Of Protein Tyrosine Phosphatase-1B,Phosphatidylinositol 3-kinase And Glucose Transporter-4 In Placental Tissues Of Gestational Diabetes Mice

Objective:By examining the effects of vitamin D（VitD）on the expression of protein tyrosine phosphatase-1B（PTP-1B）,phosphatidylinositol 3 kinase（PI3-K）,and glucose transporter-4（GLUT-4）in placental tissues of gestational diabetes mellitus（GDM）mice,the possible mechanism for vitamin D to improve glucose metabolism and IR in GDM mice was explored.Methods:30 female and 15 male C57BL/Ks J（wild type,WT）mice aged 4-5 weeks were selected and raised in an open system at room temperature of 18℃²8℃and relative humidity of 40%⁷0%;8 heterozygous female mice of 4-5 week old VDR gene knockout,4 male mice,were raised in independent ventilated cages in the SPF animal breeding room of the school.Female and male mice were reared in 2:1 cages during the estrus period,observation of vaginal plug and mobile sperm simultaneously under the light microscope was recorded as the first day of pregnancy,VDR knockout mice were taken out of single cages and raised,and 1-3 C57BL/Ks J mice were raised per cage.After conception,they were randomly divided into normal pregnancy group（NC group,n=10）,gestational diabetes group（group A,n=10）,gestational diabetes+VitD intervention group（group B,n=10）,gestational diabetes+VitD Intervention+VDR gene knockout group（group C,n=8）.After GDM mice were fed high-sugar and high-fat diet for 4 weeks,all GDM mice were injected intraperitoneally with 25 mg/kg streptozotocin on the first day of pregnancy;NC group:single intraperitoneal injection of equal amount of sodium citrate buffer on the same day.Criteria for successful GDM modeling:non-fasting blood glucose is measured at 4 days of pregnancy.If the blood glucose is≥6.7 mmol/L,the model is successfully copied.After the model is successful,continue feeding with high sugar and high fat feed.The pregnant rats in Group B and Group C were given an intragastric administration of 1,25-dihydroxy vitamin D₃[1,25（OH）₂D₃]dissolved in 0.05ml of peanut oil 0.03ug/（k?d）every morning from the 8th day of pregnancy to the 14th day of pregnancy,NC group and group A were given the same amount of peanut oil by gavage,and the mice were sacrificed on the 19th day of pregnancy,and detection of general biochemical indicators,using RT-PCR and Western blot to detect the mRNA and protein expression of mice in each group.Results:Compared with the NC group,the levels of FPG,FINS,HOMA-IR,TG,and TC increased in groups A and C,while the level of HDL-C decreased（P<0.05）;compared with group A,B Group FPG,FINS,HOMA-IR,TG,TC,LDL-C levels decreased,HDL-C level increased（P<0.05）,while group C FPG,FINS,HOMA-IR,TG,TC and LDL-C levels were significantly increased,and HDL-C level were significantly decreased（P<0.05）;compared with group B,group C FPG,FINS,HOMA-IR,TG,TC,LDL-C The level was significantly increased,and HDL-C level were significantly decreased（P<0.05）.Comparison of PTP-1B,PI3K and GLUT-4 mRNA and protein expression in mice of each group:Compared with NC group,the expression levels of PTP-1B mRNA and protein in group A and group C increased,and PI3K and GLUT-4 mRNA and protein expression The average level decreased（P<0.05）,but there was no statistically significant difference in the expression levels of PTP-1B mRNA and protein in group B（P>0.05）.The average level of PI3K and GLUT-4 mRNA and protein expression decreased（P<0.05）;Compared with group A,the expression levels of PTP-1B mRNA and protein in group B decreased,and the expression levels of PI3K and GLUT-4mRNA and protein increased（P<0.05）,while the expression levels of PTP-1B mRNA and protein in group C increased significantly.PI3K and GLUT-4 mRNA and protein expression levels were significantly reduced（P<0.05）;compared with group B,PTP-1B mRNA and protein expression levels were significantly increased in group C,while PI3K and GLUT-4 mRNA and protein expression levels were significantly reduced（P<0.05）.Conclusion:Vitamin D may improve the glucose metabolism and IR by up-regulating the expression of PI3K and GLUT-4 in the placental tissue of GDM mice and down-regulating the expression of PTP-1B.