A time course study demonstrating RNA stability in postmortem skin.

Knowledge of the factors regulating the rate of mRNA degradation, including postmortem delay, is important in determining the reliability of gene expression patterns in dermal tissue. Since RNA stability can be tissue dependent, this study evaluates the effect of postmortem interval on the integrity of total RNA or the levels of representative mRNA species in murine cutaneous tissue. Pieces of fresh skin tissue were excised for periods of 0-60 min from SKH-1 female hairless mice that were maintained at room temperature post-sacrifice. Total RNA was subsequently isolated and RNA integrity from each specimen was evaluated. Bioanalyzer profiles showed no apparent change in 28S/18S rRNA ratio or RNA integrity number at time points up to 60 min. Changes in mRNA expression levels of five selected genes were determined by real-time quantitative PCR. There were no statistical differences in the relative gene expressions of Ccnd1, Hif1alpha, cMyc and Cyr61 as a function of postmortem interval. Our data suggest that the molecular quality of cutaneous tissue is well preserved for at least 60 min after death, which can be regarded as important information for consideration of the order for tissue procurement in in vivo studies and acute ex vivo dermal studies.