MicroRNA expression profiling in diabetic GK rat model

MicroRNAs (miRNAs), which are a newly identified class of small single-stranded non-coding RNAs, regulate their target genes via post-transcriptional pathway. It has been proved that miRNAs play important roles in many biological processes. To better understand miRNA function with type 2 diabetes, we have used an oligonucleotide microarray to monitor miRNA expression profiles of GK and Wistar rats’ muscle. We found 7 miRNAs were down-expressed and 2 were over-expressed in the muscle of GK rats. Among them, miR-24 showed the most prominent change. P38 MAPK, which is a direct target of miR-24 also showed expression difference. All the data give a clue that miR-24 might be associated with diabetes through down regulation of p38 MAPK. In this study we used male GK rats, which were established by selectively breeding of normal Wistar rats with signs of impaired glucose tolerance, as type 2 diabetes model and male Wistar rats as control. Rats were housed in a temperature-controlled room and were given free access to water and standard laboratory chow during the 14 weeks. The blood glucose levels of the rats were measured each other day up to 4 times before being killed. We used microarray to monitor rat miRNA expression profile in the course of diabetic. For each sample, two independent small RNA libraries (biological replications) were generated and two independent reverse transcriptions/amplifications/hybridizations (technical replications) were performed for each library.