Abstract
OBJECTIVES: To study the effect of high-fat diet for maternal Sprague-Dawley rats at different stages on glucose and lipid metabolism in offspring and related mechanisms. METHODS: According to the diet before pregnancy and during pregnancy and lactation, maternal rats were randomly divided into four groups (n=9 each): CC (control diet before pregnancy and during pregnancy and lactation), HC (high-fat diet before pregnancy and control diet during pregnancy and lactation), CH (control diet before pregnancy and high-fat diet during pregnancy and lactation), and HH (high-fat diet before pregnancy and during pregnancy and lactation), and all offspring rats were given control diet after weaning. The body weight of maternal rats was recorded before and during pregnancy. Male offspring rats were selected from each group at the juvenile stage (3-week old) and the adult stage (12-week old) to measure the levels of fasting blood glucose (FBG) and fasting insulin (FINS) and the levels of triglyceride (TG) and total cholesterol (TC) in the liver. Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) index was calculated, and the area under the curve (AUC) was calculated for glucose tolerance test (GTT) and insulin tolerance test (ITT). Lipid deposition in the liver was observed, and the mRNA and protein expression levels of the key genes in glucose and lipid metabolism (IR, IRS, and AKT), FASN, SREBP1c, and PPARα in the liver were also measured. RESULTS: Compared with the control diet groups (CC and CH groups), the groups with high-fat diet before pregnancy (HC and HH groups) had a significant increase in body weight (P<0.001). Compared with the CC group, the HC, CH, and HH groups had a significantly greater increase in body weight (P<0.001). Compared with the CC group, the HC, CH, and HH groups had significant increases in body weight, the levels of TG and TC in the liver, and the mRNA and protein expression levels of FASN, SREBP1c, and PPARα in the offspring rats at week 3 after birth (P<0.05), as well as a significant increase in lipid deposition in the liver, with the most significant increase of the parameters in the HH group. Compared with the CC group, the HH group had significant increases in the levels of FBG and FINS, HOMA-IR index, GTT-AUC, ITT-AUC, and the protein expression level of p-IRS in the liver and significant reductions in the mRNA and protein expression levels of IR and IRS in the liver in the offspring rats at week 3 after birth (P<0.05). Compared with the CC group, the HC, CH, and HH groups had significant increases in body weight, the levels of FBG and FINS, HOMA-IR index, GTT-AUC, ITT-AUC, the levels of TG and TC in the liver, protein expression level of p-IRS in the liver, and the mRNA and protein expression levels of FASN, SREBP1c, and PPARα in the offspring rats at week 12 after birth (P<0.05), as well as a significant increase in lipid deposition in the liver, with the most increase of the parameters in the HH group. Compared with the CC group, the HC, CH, and HH groups had significant reductions in the mRNA expression levels of IR, IRS, and AKT and the protein expression levels of IR, IRS, and p-AKT in the offspring rats at week 12 after birth (P<0.05). There were no significant differences in the levels of glucose and lipid metabolism between the HC and CH groups at various stages (P>0.05). CONCLUSIONS: High-fat diet for rats at different stages before and after pregnancy has different effects on glucose and lipid metabolism of offspring rats, and high-fat diet before pregnancy and during pregnancy and lactation has the greatest effect. The effect of high-fat diet on glucose and lipid metabolism of offspring rats is considered associated with the changes in the expression of genes involved in glucose and lipid metabolism.