Microarray analysis of the miRNA levels in plasma from healthy donors

To further understanding of mature microRNA in plasma from healthy people, we have employed microRNA microarray as a discovery platform with the potential to identify the plasma microRNA levels of healthy people. Human peripheral blood was drawn from 4 healthy donors, and plasma was obtained by two-step centrifugation. Equal of total RNA from the plasma was detected by microRNA microarray including 866 human and 89 human viral miRNAs (Sanger miRBase, release 12.0). About 170 miRNAs could be detected by microarray in all 4 samples of plasma. Among them, 6 microRNAs (miR-451, miR-16, miR-133a, miR-1, miR-499 and miR-208a) were detected in the RNA from the same plasma by real-time PCR. Freshly peripheral bloods from 4 healthy donors were drawn into EDTA tubes, and were processed within 1 hour by two-step centrifugation to remove the blood cells and the cellular debris. Small RNA was prepared using the mirVana PARIS kit, and was quantified using a NanoDrop-1000 spectrophotometer. Equal of RNA from the plasma was detected by microRNA microarray to identify the microRNAs levels in plasma of healthy people.