Study Of The Gene Expression Profile In Kidney Tissuse Of Type 2 Diabetic Rats

Objectives: To compare Gene expression profile in kidney tissue between type 2diabetic rats and normal controls by DNA microarray and to study the pathogenesis oftype 2 diabetic nephropathy.Methods: (1) Rats(male SD)were randomly sssigned to trial group(n=12)and normalgroup(n=10),Diabetic model of rats were induced by streptozocin(25mg/kg) and 10weeks'of rich fat diet.(2)The weight of the rats and the levels of blood glucose,insulin,lipid were identified. (3)The mRNA was isolated and purified from kidneytissue of two groups rats, and reverse transcribed to cDNA with Cy3-dUTP andCy5-dUTP separately to prepare hybridization probes.(4)The mixed probes werehybridized to cDNA microarray which contains 4000 genes and the fluorescentsignals were scanned.(5) Semi-quantitative RT-PCR validation was performed onsome genes which have differential expression.Results: (1)The body mass,serum triglyceride,fasting blood glucose and fastinginsulin of trial group(diabetic rats) were significantly increased, but glucose tolerancewas impaired and the insulin sensitivity index was decreased after 12 weeks whencompared with controls. (2) 399 genes were expressed differently between two groups.267genes were downregulated and 132genes were upregulated in type 2 diabetic ratcompare with the control. Genes related to lipid metabolism,oxidantive stress,apoptosis,ECM synthesis and blood coagulation were expressed higer level in tissueof diabetic rats than in control tissue;genes related to glucose and energymetabolism,insulin signal transduction,ECM degration and fibrinolytic wereexpressed lower.(3) Using RT-PCR approach,we have validated three genes transcriptexpression levels. For each of the three genes, mRNA levels showed trends similar tothose of the microarray experiment.Conclusions: (1) This rat model of type 2 diabetes were characterized by obesity,hyperglycemia ,hypertriglyceride and insulin resistance, which resembles theclinical manifestation of type 2 diabetes.(2)Confusion of material and energymetabolism, reinforce of oxidant stress, disorder of blood coagulation and fibrinolyticsystem,may play important roles in the pathogenesis of diabetic nephropathy.