Gene expression profiling of sciatic nerves from rats with diabetic peripheral neuropathy

To identify the key genes and pathways which might play critical roles in the pathogenesis of experimental DPN via microarray analysis. Adult male Sprague-Dawley rats (initial weight 250-300g, from the department of laboratory animal science of Fudan University) were randomly assigned into two groups: control rats and diabetic rats. Diabetes was induced with a single intraperitoneal injection of STZ (55mg/kg). Control rats were performed with a single intraperitoneal injection of 0.9% saline solution. Glucose level was evaluated using Sannuo strips on tail vein blood at day 3 after STZ injection and verified again at day 7 after STZ injection. Only rats with blood glucose level 16.7 mmol/L were considered diabetic.Six weeks after diabetes induction, nerve tissue samples (about 1cm long) were harvested from the right sciatic nerve of rats in control (n=3) and diabetic (n=3) groups for total RAN isolation. Microarray hybridization was then performed according to the Agilent One-Color Microarray-Based Gene Expression Analysis protocol (Agilent Technologies). Quantile normalization and subsequent data processing were performed using the GeneSpring GX v12.1 software package (Agilent Technologies). The univariate t-test with a fold-change >2 and P value < 0.001 was applied to identify the DEGs between control rats and diabetic rats. Credibility of the microarray data was validated through qRT-PCR on 4 genes. Total RNA was independently extracted from the right sciatic nerve of rats in both groups (n=3) 6 weeks after diabetes induction. Six weeks after diabetes induction, nerve tissue samples (about 1cm long) were harvested from the right sciatic nerve of rats in control (n=3) and diabetic (n=3) groups for total RAN isolation.