A Simple Approach for Evaluating Total MicroRNA Extraction from Mouse Brain Tissues

Abstract

For the analysis of microRNA, a common approach is to first extract microRNA from cellular samples prior to any spe-cific microRNA detection. Thus, it is important to determine the quality and yield of extracted microRNA. In this study, solid-phase extraction was used to isolate small RNA (<200 nt), which included microRNA, from mouse brain tissues. By using standard UV absorbance measurements, the amount of small RNA in the extracted RNA samples was deter-mined. To determine the presence of microRNA, each RNA sample was analyzed by PAGE with SYBR ® Green II staining. Testing for contamination of any small DNA fragments, RNase and cellular peptides or proteins were system-atically carried out. By scanning the gel image obtained from PAGE analysis, the average percentage of total mi-croRNA (19 -25 nt) in the extracted RNA samples was determined to be equal to 2.3% ± 0.5%. The yield of total mi-croRNA was calculated to be ~0.5 ng of microRNA per milligram of frozen mouse brain tissue. In comparison to other methods that require the use of expensive specialized instrumentation, the approach of combining the standard UV ab-sorbance and PAGE analysis represents a simple and viable method for evaluating the quality and yield of microRNA extraction from tissue samples.