| PurposeIn the past decade,several epidemiological studies have shown that intrauterine growth retardation(IUGR) infants prone to insulin resistance,obesity,type 2 diabetes,cardiovascular disease in adulthood.Insulin resistance is the central aspect of metabolic syndrome.Exercise is one of the important ways to prevent insulin resistance.We establish the IUGR model of Sprague-Dawley rats,observe their growth and development status and insulin sensitivity,and investigate the effect of exercise on insulin sensitivity in IUGR rats.Methods1.The IUGR animal model is established by maternal nutrition restriction during pregnancy.Timed matings are proceeded in SD male and female rats.The dams are randomly divided into starvation group and control group.The foods are available adlibitum throughout the pregnancy to the control group,and the intakes of the female rats in the starvation group are limited as the 50%intakes of the control group.The birth weight is below the mean value of the birth weight in the control group more than two standard deviation is defined as IUGR.2.48 3-week-old male rats are randomly assigned into six groups:3-week IUGR Model group(M3),3-week Control group(C3),IUGR Model 12 group(M12),IUGR Model Exercise group(ME12),Control 12 group(C12),Control Exercise 12 group(CE12).The rats in group M3 and C3 are killed at their 3-week.Then the serum parameters are measured and the main organs are weighed.The rats in group ME12 and CE12 exercise 8 weeks.After 8 weeks exercise,the rats in group ME12,CE12,M12 and C12 are killed.Then the serum parameters are also measured and the main organs are weighed.Results1.The effects of intrauterine growth retardation on growth and developmentThe average birth weight and length of IUGR group are significantly lower than the control groups(P＜0.05).After 3 weeks,the rats of group M3 reach to the average level of group C3 And the weight of internal organs in group M3 rats are generally lower than group C3.Except the weight of brain tissue,the weight of heart,liver and kidney in group M3 rats compared with the group C3 have a very significant difference(P＜0.01).Group M12 rats are obese at 12-week with perinephric fat pads significantly increased,compared with group C12 rats(P＜0.01).2.The effects of intrauterine growth retardation on abnormal metabolism and insulin sensitivityCompared with group C3,IRI is higher(P＜0.01) and ISI is lower in 3-week group M3 rats(P＜0.05);The FINS,FPG,TC and TG are higher(P＜0.01),but HDL-C and LDL-C have no statistic difference.Compared with group C12,IRI is higher(P＜0.01) and ISI is lower in 12-week group M12rats(P＜0.01);The FPG,TC,TG and HDL-C are higher(P＜0.01),LDL-C are lower(P＜0.05),but FINS have no statistic difference.3.The effects of exercise on insulin sensitivityAfter 8 weeks of exercise,compared with group M12,IRI is lower(P＜0.01) and ISI is higher(P＜0.01) in group ME12 rats.But Compared with group C12,the IRI and ISI of group ME12 have no statistic difference.Compared with group M12,the FPG,TC(P＜0.05),TG, LDL-C,FFA,TNF-α(P＜0.05) and Leptin(P＜0.05) in group M12 are lower(P＜0.01), HDL-C are higher(P＜0.01),but FINS have no statistic difference.Compared with group C12,the indicators of glycolipid metabolism,FFA and TNF-αin group ME12 had no statistic difference.Conclusions1.Exposed to protein malnutrition during pregnancy can induce IUGR.The IUGR rats catch up growth after birth.,and the main organs of 3-week IUGR rats are growth restriction except brain tissue.The growth of main organs have no statistic difference with the normal rats,but abdominal obesity appear and visceral fat weigh increase in12-week IUGR rats.2.3-week IUGR rats have abnormal glucose and lipid metabolism,insulin sensitivity reduced.The glucose and lipid metabolism of 12-week IUGR rats have serious disorder, insulin resistance increased3.After 8 weeks exercise,the insulin sensitivity ot IUGR rats improve.The mechanisms of exercise amehorate the insulin sensitivity in IUGR rats arc probably as follows:①exercise Significantly improve the glucose and lipid metabolism;②exercise reduce the concentration of Serum FFA,TNF-α,Leptin.
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