RNAprotect Saliva: An Optimal Room- Temperature Stabilization Reagent for the Salivary Transcriptome

Quantitative analysis can now be performed on a panel of human salivary mRNAs identified as potential markers for oral cancer (1)(2). Translational and clinical applications of salivary transcriptome diagnostics require RNA degradation in saliva to be stopped at the time of collection and until analysis, preferably with room-temperature–compliant stabilization reagents.We compared 3 RNA stabilizing reagents for their abilities to stabilize salivary RNA at room temperature: SUPERase·In™ RNase Inhibitor (SI), RNA Later ® (RL), and RNAprotect® Saliva Reagent (RPS). We incubated saliva samples with these reagents and control saliva samples with no stabilization reagent for up to 7 days at room temperature. We isolated RNA with the RNeasy Micro Kit (QIAGEN Inc.), and measured the amount of salivary β-actin mRNA with reverse-transcriptase quantitative PCR (RT-qPCR). The cycle threshold (CT) values increased rapidly after 1 h for control and SI samples (Fig. 1A⇓ ). The RL sample also exhibited an increase in CT value starting at day 1, and its CT value at day 7 was the highest of all the samples. RPS saliva samples, unlike the SI, RL, or control samples, did not show a …