Relationship Between Expression Of Fetal Liver Fatty Acid Synthesis Key Enzymes And Fetal Body Fat Accumulation In Gestational Diabetes Millitus Offspring Mice

Objective: The study was to explore the establishment of a mouse model of gestational diabetes millitus by feeding the high-fat diet during the short-term pre-pregnancy plus pregnancy period.To investigate the relationship between expression of fetal liver fatty acid synthesis key enzymes and fetal body fat accumulation in gestational diabetes millitus mice.To provide a scientific experimental evidence for elucidating the mechanism of LGA in the offspring of gestational diabetes millitus.Methods: After seven-week-old C57BL/6J female mice were acclimation feeding for one week,all mice were randomly divided into control group and model group.Mice in control group were fed with standard diet,mice in model group were fed with high fat diet.The female mice were mate when fed for 1 week,10 days and 2 weeks.The next day,successful mating was confirmed by presence of a vaginal mucous plug at dawn,which represented gestation day(GD)0.5.All pregnant mice maintain their original feed during pregnancy.Mice were regularly measured for body weight.Female mice were subjected to the IPGTT at the beginning of the experiment and at GD0.5,GD11.5,and GD16.5.The blood glucose level of the tail tip at 0 min,15 min,30 min,60 min,90 min,and 120 min was recorded for each test.According to the results of the IPGTT,it is judged whether the GDM model is successful.GDM pregnant mice were executed after measuring body weight and fasting blood glucose in the morning of GD 18.5 days,and collected pregnant mouse eye blood,liver,fetal and placenta.The fetal body weight,body length,and placental weight were measured.Soxhlet extraction method was used to determine the body fat percentage of fetal mice.The serum insulin level was detected by ELISA kit.The protein and gene expression levels in fetal liver were detected by western blot and q PCR.Results:(1)There was no significant difference in AUC of the IPGTT between model group and control group at the beginning of the experiment(P>0.05).Compared with control group,the AUC were higher in model group 1w and model group 10 d at GD0.5,but there is no significance(P>0.05),the AUC was significantly higher in model group 1w and model group 10 d at GD11.5 and GD16.5(P<0.05).The AUC of the model group 2w was higher than in the control group at GD0.5,GD11.5 and GD16.5(P<0.05).(2)There was no difference in body weight between model group and control group at the beginning of the experiment(P>0.05).There was no difference between body weight of model group 1w and the control group 1w at GD0.5(P>0.05),but significantly higher than the control group 1w at GD11.5 and GD16.5(P<0.05).The body weight of model group 10 d was higher than the control group 10 d at GD0.5,GD11.5 and GD16.5(P<0.05).(3)The levels of TG,HDL-C and LDL-C in the blood of pregnant mice in model group 1w and model group 10 d at GD18.5 were not significantly different from control group(P>0.05);TCH levels were higher than those in the control group(P<0.05).(4)Oil red staining of liver sections showed that the lipid droplets in the model group 1w and the model group 10 d were significantly increased compared with the control group,the lipid droplets were larger and the liver cells were more disordered.(5)There was no significant difference in fasting blood glucose level between model group 1w and model group 10 d at GD18.5 compared with control group(P>0.05).Fasting serum insulin levels and HOMA-IR index were higher in model group 1w and model group 10 d than control group(P<0.05).(6)The body weight and body fat percentage of fetal in model group 1w and model group 10 d was higher than that in control group(P<0.05).The placental weight of the model group 1w was no different from the control group(P>0.05),and the placenta weight of the model group 10 d was lower than that of control group(P<0.05).The length of fetal and the weight of the placenta plus fetal in model group 1w and model group 10 d was no significant difference compared with control group(P>0.05).(7)In the model group 1w and the model group 10 d,the oil red O staining of the fetal liver section showed scattered small lipid droplets,while the fetal liver sections of the control group only occasionally showed small lipid droplets and the size was significantly smaller than the model group.(8)The liver TG levels of the fetal mice in model group 1w and model group 10 d were significantly higher than control group(P<0.05),and the levels of TCH,HDL-C and LDL-C were not significantly different from control group(P>0.05).(9)Compared with control group,the m RNA expression of AMPK?1 in the fetal liver of the model group 1w and the model group 10 d was down-regulated(P<0.05),and AMPK?2,SREBP-1C,ACC1,FASN and SCD1 was significantly up-regulated(P<0.05).(10)The protein levels of SREBP-1C in the liver of the model group 1w and model group 10 d were higher than control group,the ratio of p-AMPK?/AMPK? and p-ACC1/ACC1 was significantly lower than control group,and the protein levels of FSAN and SCD-1 were higher than control group.Conclusion:(1)C57BL/6J mice were fed 45% high-fat diet 1 week or 10 days before pregnancy,and 45% high-fat diet during pregnancy,which induced normal glucose tolerance before pregnancy and impaired glucose tolerance in the second and third trimester of pregnancy.And there is insulin resistance,excessive gestational weight gain,LGA and other phenotypes similar to human gestational diabetes millitus,which better simulates the characteristics of human gestational diabetes millitus.It is a relatively successful animal model of gestational diabetes.It provides a new method for the preparation of animal models for the study and intervention of gestational diabetes mechanisms.(2)Fetal of GDM mice showed higher body fat percentage.The AMPK/ACC pathway and the SREBP-1C regulatory pathway in the liver of fetal mice increase the accumulation of body fat in fetal mice.Fetal mice use glucose to synthesize more fatty acids,Fetal rats use glucose to synthesize more fatty acids,which causes excessive body fat in fetal mice.This will help to further reveal the mechanism LGA of human GDM,so as to better intervene in pregnancy outcomes and reduce the incidence of LGA.