RT-rtPCR quantification of circulating microRNAs in plasma and serum samples from healthy domestic cats

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at a post-transcriptional level by silencing targeted messenger RNA (mRNA). Most studies concerning miRNA expression use solid tissue samples. However, circulating miRNAs from different body fluids have recently emerged as diagnostic and prognostic molecules, given that they hold informative value and have increased stability in cell-free form. Blood sampling of cats can be challenging given their small body size and because they often experience distress when handled. We quantified miR-20a, -192, -365, -15b-5p, and -16-5p from plasma and serum samples of 10 healthy domestic cats. Our RT-rtPCR procedure used 100 µL of either plasma or serum samples as sources of biomarker molecules. However, serum provided higher amounts of miRNA than plasma samples, with a p < 0.0001 for miR-20a and p < 0.0002 for miR-16-5p.