The Mechanisms Of Insulin Resistance In Skeletal Muscle From Intrauterine Growth Retardation Rats With Catch-up Growth

Objective In the past decade, several epidemiological studies have shown a relationship between intrauterine growth retardation (IUGR) and insulin resistance, which is the high risk of type 2 diabetes and cardiovascular disease in later life.Furthermore, IUGR are at increased risk for short stature and type 2 diabetes mellitus as a result of growth hormone(GH) resistance and insulin resistance.Methods A Thirty female rats with weight ranging from 200 to 250 g and 10 male rats with 300–400 g were used in this study. The first day of pregnancy was defined by the presence of sperm on the vaginal smear. Natural labor occurred on day 21–22 of gestation. New born pups born to dams without prenatal food restriction made up normal appropriate for gestational age (AGA) control rats. IUGR rat model was developed by prenatal food restriction throughout pregnancy (30% of normal intake, 7.5 g/day). 5 newborn IUGR pups were breast-fed by a maternal and 8 normal newborn control pups were breast-fed by a maternal. Recorded the measurement of body weight and body length every week. pups and control pups randomly selected were executedwith skeletal muscle tissue. Total RNA of skeletal muscle tissue was extracted using TRIZOL Reagent. The mRNA expression levels of IRS-1, IRS-2, SOCS-1, SOCS-2, SOCS-3,Pi3K were detected by Real-Time PCR. Immunohistochemical stainings were used to analyse SOCS-2 proteins.Result There was no significant difference in IRS-1 mRNA of the skeletal muscle between IUGR and AGA at the age of 1 and 3 weeks of age and that of IUGR decreased at the ageof five and seven weeks compared to AGA.The IRS-2 mRNA of the skeletal muscle increased significantly at the age of 1 weeks in IUGR compared to AGA,and at the age of 3,5 and seven weeks, that of IUGR lower than AGA。The SOCS-1 mRNA levels in skeletal muscle of IUGR were increased compared to AGA from the age of 1 to 7 weeks. There was no significant difference in SOCS-2 mRNA of the skeletal muscle between IUGR and AGA at the age of 1 and 7 weeks of age , that of IUGR increased significantly at the age of 3 and 5 weeks compared to AGA. The SOCS-3 mRNA level in the skeletal muscle of IUGR increased significantly at the age of 1, 3, 7 weeks comared to AGA, that of IUGR is no difference compared to AGA at the age of 5 weeks. The Pi3K mRNA levels in skeletal muscle of IUGR were lower significantly than AGA at the age of 1, 3, 5 and 7 weeks.Conclusion The undernutrition in the intrauterine can influence the insulin resistance of IUGR rats and the levels of the meluculars in insulin signal pathway and SOCS-1,SOCS-2,SOCS-3 of skeletal muscle.