Effect Of Maternal High-fat Diet During Pregnancy And Lactation On Glucose And Lipid Metabolism And Related Gene Expression In Offspring's Liver

Background and PurposeIn recent years,the academic community has increasingly focused on the effects of early-life environments on diseases during individual growth and adulthood.A large number of epidemiological and animal studies had shown that if exposed to adverse developmental environments during the fetal period and early postnatal period,the body's metabolism,immune stress,and endocrine hormone levels will change,forming a specific metabolic pattern that will eventually lead to disorders of glycometabolism,disorders of lipid metabolism,hypertension,coronary heart disease,etc.The impact of this early-life environment on adulthood disease has now been formally named by the academic community as the "developmental origins of health and disease(DOHaD)" doctrine.The maternal high-fat diet is one of the important factors that cause the adverse developmental environments in the early life.Studies have shown that high-fat diet during pregnancy and lactation may lead to glucose and lipid metabolism disorders,cardiovascular disease in individual growth and adulthood,and have gender differences.But there are major differences between domestic and international reports,and the mechanism is still to be explain.Therefore,in this study,a cross-generation C57BL/6J mouse model was established to observe the biochemical markers and liver pathological changes related to glucose and lipid metabolism in offsprings with maternal high-fat diet during pregnancy and lactation,then to examine the expression of key mRNAs to explore the potential mechanism of metabolic disorders,and to provide a theoretical basis for the prevention of metabolic diseases.Methods1.Thirty-two C57BL/6J mice of 6-week-old were selected,half were male and half were female.After 2 weeks of adaptive feeding,8-week-old female mice were mated with normal-diet and normal-active male mice.The date of the occurrence of vaginal plug was the first day of pregnancy.Pregnant female mice were randomly divided into high-fat diet group(containing 60 kcal% fat)or normal chow diet group(containing 10 kcal% fat)during pregnancy and lactation.After the birth of offspring,according to gender divided into 4 groups: M-HF group(high-fat diet group,male offspring),group M-NC(normal chow diet group,male offspring),F-HF group(high fat diet group,female offspring)and F-NC group(normal chow diet group,female offspring).2.At 3 weeks after delivery,then wean and give normal diet to the offspring.Weighing and taking blood from the orbit at 4 weeks(early adolescence),8 weeks(sexual maturity)and 18 weeks(adult).The fasting blood glucose,total cholesterol(TC),triglyceride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C),alanine aminotransferase(ALT),aspartate aminotransferase(AST),glutamyltranspetidase(GGT)were detected by automatic biochemical analyzer;the fasting insulin was detected by Enzyme Linked Immune Sorbent Assay(ELISA).The offspring mice were killed at the age of 18 weeks,and the liver specimens were left.The liver tissue morphology was observed by oil red staining.3.The expression of glucose metabolism related genes in the liver was detected by RT-PCR detection including: the mRNA expression of Akt serine/threonine kinase 2(Akt2),insulin receptor substrate 1(IRS1),insulin receptor substrate 2(IRS2)in insulin signaling pathway;the mRNA expression of pyruvate carboxylase(PC),phosphoenolpyruvate carboxykinase(PEPCK),fructose-1,6-bisphosphatase 1(FBP1),glucose-6-phosphatase(G6P)in the gluconeogenesis process;the mRNA expression of glucokinase(GK),6-phosphofructokinase-1(PFK-1),pyruvate kinase(PK)in glycolytic pathway.4.The expression of lipid metabolism related genes in the liver of RT-PCR detection including: the mRNA expression of acetyl CoA carboxylase(ACC),fatty acid synthase(FAS),diacylglycerol acyltransferase(DGAT)in triglyceride synthesis process;the mRNA expression of hormone-sensitive lipase(HSL),Carnitine palmityl transferase-?(CPT-I),peroxisome proliferator activated receptor alpha(PPAR-?)in triglyceride decomposition process;the mRNA expression of HMG-CoA reductase(HMGCR)and sterol regulatory element binding protein 2(SREBP-2)in the cholesterol synthesis process.Results1.At 4-week-old(pre-puberty),fasting insulin in the M-HF group had a tendency to increase compared with the M-NC group,but the difference was not statistically significant(P>0.05);the other indicators were not statistically significant(P>0.05).Compared with F-NC group,there was no significant difference in each index of F-HF group(P>0.05).2.At 8-week-old(sexual maturation),fasting insulin,ALT,and AST levels increased in the M-HF group compared with the M-NC group(P<0.05);serum TG and LDL-C levels increased,but differences were not statistically significant(P>0.05).Compared with F-NC group,fasting insulin,TC,TG,ALT and AST levels in F-HF group increased(P<0.05).3.At 18-week-old(adulthood),serum TG levels in the M-HF group were significantly higher than those in the M-NC group(P<0.05);serum ALT and AST levels were still higher in the F-HF group than in the F-NC group at a higher level(P<0.05);oil red O staining results showed that compared with M-NC and F-NC groups,the lipid droplet content in M-HF group and H-HF group increased.4.The results of glycometabolism related gene expression showed that compared with group NC,the mRNA expression of IRS1,IRS2,PC,PEPCK,GK,PFK-1 mRNA and PK increased in group M-HF(P<0.05).The mRNA expression of IRS2,PC,PEPCK,G6 P,GK and PFK-1 in F-HF group was up-regulated(P<0.05).5.The expression of lipid metabolism related genes showed that compared with the NC group,the mRNA expression of ACC,DGAT1,DGAT2,CPT-I,PPAR-a,HMGCR and SREBP-2 in the M-HF group was increased(P<0.05).The mRNA expression of ACC,FAS,DGAT1,CPT-I,PPAR-a,HMGCR and SREBP-2 in the group F-HF was increased(P < 0.05).Conclusion1.The maternal high-fat diet during pregnancy and lactation led to increased fasting insulin levels,abnormal lipid metabolism,and abnormal liver function during the sexual maturation stage of the offspring.It was remission in adulthood,but the liver fat content was still high,and the high levels of triglycerides in male offspring abnormal liver function in female offspring were still persist.2.The mRNA expression of hepatic insulin signaling pathway,gluconeogenesis,and glycolysis pathway was overall higher in adulthood;the high mRNA expression of IRS1,IRS2,GK,PFK-1,PK in male and IRS2,GK,PFK-1 in female may be involved in the remission of fasting insulin level in adulthood.3.The mRNA expression of triglyceride synthesis,triglyceride breakdown and cholesterol synthesis was overall higher in adulthood;the high mRNA expression of CPT-I and PPAR-? in offsprings may be involved in the remission of blood lipids and abnormal liver function in adulthood.