Expression Of Insulin Receptor Substrate In Livers, Muscles And Pancreas Of Young Rats With Intrauterine Growth Retardation

In the past decade,several epidemiological studies have shown a relationship between intrauterine growth retardation(IUGR) and insulin resistance,type 2 diabetes and cardiovascular disease in adulthood.Insulin resistance is the important aspect of the metabolic syndrome.Insulin receptor substrate is the important protein in the insulin pathway.Their expression levels can impact insulin resistance,Protein and amino acids deficiency are critical factors in chronic malnutrition.we established IUGR rat model by protein malnutrition during pregnancy and investigated the expression of insulin receptor substrate-1(IRS-1)and insulin receptor substrate-2 (IRS-2) in liver,muscles and pancreas of the IUGR rats.MethodsAn IUGR animal model was established by protein malnutrition during the mother pregnancy.8 newborn IUGR pups,3weeks,8weeks pups and 8 newborn, 3weeks,8weeks control pups randomly selected were executed,their liver,muscles and pancreas were obtained.The incidence of IUGR and average birth weight were calculated.Total RNA of liver,muscles and pancreas were extracted using TRIZOL reagent.The expression of IRS-1 and IRS-2 mRNA were detected by RT-PCR.Western blot was undertaken to analysis proteins expression of IRS-1,IRS-2。ResultsBody weights,body length of IUGR rats were significantly lower than normal control rats at the same age.The expression levels of IRS-2 mRNA in liver tissues of newborn IUGR rats were significantly lower than that of control group.IRS-1 mRNA relative expression level in liver tissues of newborn IUGR rats had no significant difference with that in newborn control rats.IRS-1 mRNA relative expression levels in muscles of newborn IUGR rats were significantly lower than that of control group respectively.IRS-2 mRNA relative expression levels in muscles of newborn IUGR rats had no significant difference with that in newborn control rats.IRS-1 mRNA relative expression levels in pancreas of newborn IUGR rats had no significant difference with that in newborn control rats.IRS-1 mRNA relative expression levels in tissues and pancreas of IUGR rats at wk 4 had no significantly difference between the two groups. IRS-1 mRNA relative expression levels in muscles of IUGR rats at wk 4 were significantly levels in liver tissues and pancreas of IUGR rats at wk 4 significantly lower than that of control group respectively.IRS-2 mRNA relative expression levels in muscles at wk 4 had no significantly difference between the two groups.IRS-1 mRNA relative expression levels in liver tissues and pancreas of IUGR rats at 8 weeks of age were significantly lower than that of control group respectively.IRS-2 mRNA relative expression levels in muscles of IUGR rats at 8 weeks of age had no significantly difference between the two groups.The results of western blot analysis were consistent with those of RT-PCR.ConclusionsExposed to protein malnutrition during pregnancy can induce IUGR.The IUGR rats catch up growth after birth,and to be fatter than normal rats when grown up.IRS-2 expression levels in liver tissues.pancreas and IRS-1 expression levels in muscles of IUGR rats at new born,3 weeks 8 weeks of age significantly lower than that of normal rats at the same age,which might be one of the molecular mechanisms of IUGR having increased of metabolic syndrome.