Quantitative analysis of mRNA in human temporal bones

CONCLUSION: Well-preserved mRNA could be extracted from frozen human inner ears. Therefore, this study demonstrates that analysis of mRNA could be performed to study the molecular mechanisms of inner ear disorders using human specimens. OBJECTIVES: Analysis of RNA as well DNA is requisite to study the molecular mechanisms of inner ear disorders. Methods of isolating RNA from experimental animals have been established, while isolation of RNA from human inner ears is much more challenging. In the present study, we demonstrate a method by which messenger RNA (mRNA) was extracted from human inner ears and quantitatively analyzed. MATERIALS AND METHODS: COCH mRNA as well as GAPDH mRNA was extracted from membranous labyrinths dissected from three formalin-fixed and three frozen human temporal bones, removed at autopsy. The length of COCH mRNA and quantity of GAPDH mRNA was compared between the two groups by quantitative RT-PCR. RESULTS: COCH mRNA could be amplified as much as 976 bp in all three frozen specimens. By contrast, it was amplified to 249 bp in two of the three formalin-fixed specimens, with no amplification observed in the remaining. The quantity of amplifiable GAPDH mRNA in the formalin specimens was only 1% of that of the frozen specimens.