Related Research Of Wnt Pathway Mediating Insulin Resistance In Intrauterine Growth Retardation Rats With Catch-up Growth

Objective: Detect the expression of low-density lipoprotein receptor-related proteins(LRP6)and β-catenin,which are the key molecules of Wnt signaling pathway,and the expression of insulin receptor substrate 1(IRS-1)in the liver tissue of intrauterine growth retardation(IUGR)rats with catch-up growth,and further verify the expression of the above key molecules in rat primary hepatocytes,and explore the possible mechanism of IUGR leading to abnormal development and metabolism.Methods: 1.Establish a rat model of IUGR with catch-up growth: create a bad environment in the uterus by restricting the food of pregnant rats,and establish a rat model of IUGR with catch-up growth by reducing the number of pups per cage after birth;2.Observe the physical characteristics of rats : Record the body weight,nose-hip length and calculate the body mass index(BMI)of the offspring every week from birth;3.Detect related indexes of glucose metabolism:measure fasting serum glucose(FG)and fasting serum insulin(FIns)levels of 16-week-old rats,and calculate their homeostasis model assessment of insulin resistance(HOMA-IR);4.Detect the expression of key molecules of Wnt classic signaling pathway and insulin signaling pathway in rat liver tissue:at the 16 th week after birth,detect mRNA and protein expression levels of LRP6,β-catenin and IRS-1 in the liver tissue of catch-up growth IUGR group and control group by Real-time quantitative PCR(Real-time Quantitative Polymerase chain reaction,RT-PCR)and western blot;5.Verify the expression of key molecules of Wnt classic signaling pathway and insulin signaling pathway in rat hepatocytes: isolate and culture 16-week-old primary rat hepatocytes,and use RT-PCR and western blot to detect the mRNA and protein expression of LRP6,β-catenin and IRS-1 in the hepatocytes of rats with insulin resistant of catching-up growth IUGR group and control group both in the basal state and the insulin-stimulated state.Results: 1.One week after birth,the growth of rats in the catch-up growth IUGR group accelerated and their BMI were consistently and significantly greater than that of the control group(P <0.05);2.Compared with the control group,the levels of Flns and HOMA-IR in the catch-up growth IUGR group were significantly increased(P <0.01);3.Compared with the control group,the mRNA and protein expressions of LRP6,β-catenin and IRS-1 in the liver tissue of the 16-week-old IUGR group of rats were reduced(P <0.05);4.Consistent with the results in the tissue,the mRNA and protein expressions of LRP6,β-catenin and IRS-1 in the primary hepatocytes of rats of the16-week-old catch-up growth IUGR group were decreased both in the basal state and insulin-stimulated state compared with the control group(P <0.05).Conclusion: Intrauterine growth retardation changes the expression of the Wnt classic signaling pathway,resulting in the damage of insulin signaling,which may be one of the molecular mechanisms of insulin resistance in catching-up growth IUGR rats.