| Background: Obesity means an over-deposition of fat from disequilibrium of energy metabolism and too much intake of calorie. It influences many functions of cardiovascular system, respiratory apparatus, endocrine, endocrinium, growth, intelligence, mental growth behavior and so on in obese children. Recently, children obesity has shown an upward trend both in developed and developing countries. It has been a serious social problem which impairs children health. The ob-gene-clone and leptin, expecially the discovery of OB-R, made a new stage about the etiopathogenisis of obesity. Many experiments have confirmed that obese people have leptin resistance and insulin resistance,which are considered to be the main cause of obesity. The discoveration of SOCS-3 made obese study of leptin resistance to the signal transduction level. Since OB-R and SOCS-3 gene express mainly in hypothalamus, the clinical studies obout them are limited.Objective: We detected the expression of OB-Rb mRNA and SOCS-3 mRNA of peripheral blood mononuclear cell (PBMC) in order to obtain the potential mechanisms of leptin resistance and insulin resistance on both receptor gene level and signal transduction level.Method: 33 boys were served as obese group with BMI>23(age from 4 to 6 years old); 21 boys were served as control group with BMI between 16 and 18(the same age with obese group). Plasma was separated from 2ml venous blood which had been anticoagulated with EDTA. The levels of plasma leptin, insulin and C-peptide were measured with radioimmunity. The concentrations of plasma glucose, triglyeride and cholesterin were measured by automatic biochemistry analyzer. And the expression of OB-Rb mRNA and SOCS-3 mRNA of PBMC was examined with SYBR(R) Green I real-time RT-PCR (GAPDH as internal control).Results:1.The concentrations of plasma leptin, insulin, C-peptide, glucose, triglyceride and cholesterin in obese group were all elevated obviously compared with that of control group (p<0.005). The concentrations of plasma leptin had a significant positive correlation with the levels of both insulin and C-peptide(r =0.633, p<0.001 and r =0.619, p<0.005, respectively).2.The expression of OB-Rb mRNA in PBMC was decreased obviously in obese group compared with that of control group (0.383±0.231 vs 1.433±1.098, p<0.005). But the expression of SOCS-3 mRNA was elevated obviously in obese group compared with that of control group (1.914±1.008 vs 1.031±0.656, p<0.005).3.The concentrations of plasma leptin had a significant negative correlation with the expression of OB-Rb mRNA in obese group(r = -0.674, p<0.005); but had no relationship with the expression of SOCS-3 mRNA (r = 0.221, p>0.05).4.The concentrations of plasma insulin had a significant negative correlation with the expression of OB-Rb mRNA in obese group (r = -0.532, p<0.01); but had no relationship with the expression of SOCS-3 mRNA (r=0.347, p>0.05).5.There was no relationship between the expression of OB-Rb mRNA and SOCS-3 mRNA in obese group ( r = -0.186, p>0.05).Conclusion:1.The concentrations of plasma insulin, glucose, triglyceride and cholesterin were all elevated obviously in obese group compared with that in control group, which supports obese children have insulin resistance and glucolipid metabolic disorder.2.The concentrations of plasma leptin were elevated obviously, and had positive correlation with the levels of both insulin and C-peptide in obese group, supporting that obese children have leptin resistance, and the hypsoleptinemia may participate to the insulin resistance.3.The expression of OB-Rb mRNA in PBMC decreased obviously in obese group compared with that in control group, and had an significant negative correlation with the concentrations of both leptin and insulin, which suggests the silence of OB-Rb gene has some relationship with leptin resistance and insulin resistance.4.The expression of SOCS-3 mRNA was elevated obviously in obese group, suggesting the up-regulated SOCS-3 mRNA may participate leptin resistance and insulin resistance. |
PDF Full Text Request