RNAlater Solutions for RNA Stabilization and Storage

Invitrogen RNAlater Stabilization Solution is an aqueous, nontoxic tissue RNA stabilization and storage reagent that rapidly permeates tissues to stabilize and protect cellular RNA. RNAlater solution minimizes the need to immediately process tissue samples or to freeze samples in liquid nitrogen for later processing. Tissue pieces can be harvested and submerged in RNAlater solution for storage without jeopardizing the quality or quantity of RNA obtained after subsequent RNA isolation.

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• Immediate RNase inactivation
• Freedom from liquid nitrogen and freezers
• Minimizes freezing and grinding
• Ideal for field collection
• Flexible tissue storage
• Compatible with most RNA isolation procedures including all of the Invitrogen Ambion RNA isolation kits
• Compatible with gene expression and gene-profiling data
• Reliable tissue archiving without RNA degradation

Trim the tissue to be less than 0.5 cm in at least one dimension and simply submerge it in 5 volumes of RNAlater solution (e.g., a 0.5 g sample requires about 2.5 mL of RNAlater solution). Small organs such as rat kidney, liver, and spleen can be stored whole in RNAlater solution. Resuspend pelleted cells in a small amount of PBS before adding 5–10 volumes of RNAlater solution. Samples can be stored at 4°C for one month, at 25°C for one week, or at –20°C indefinitely. Archive tissues treated with RNAlater solution at –20°C.

For RNA isolation, simply remove the tissue from RNAlater solution and treat it as though it was just harvested. Most tissues can be homogenized directly in lysis buffer, although harder tissues such as bone may require freezing in liquid nitrogen and grinding.

RNAlater  solution has been tested on a variety of mammalian tissues, plants, E. coli, Xenopus, fish, and Drosophila. It has been successfully used with all of our Ambion RNA isolation kits (Figure 1), including RNAqueous, ToTALLY RNA, RNA WIZ, and Poly(A)Purist Kits, as well as TRI Reagent products (MRC). Other commercial RNA isolation kits and standard RNA isolation protocols are also compatible with RNAlater solution.

Recent research by Drs. Scott Florell and Sancy Leachman at the Huntsman Cancer Institute [Mod Pathol 14:116 (2001)] demonstrates that RNAlater solution does preserve the histology of tissues. A blinded study was performed in which two pathologists compared human tissue sections that were immediately processed for histology (fixed in formalin and embedded in paraffin, or frozen sectioned) to samples stored in RNAlater solution, rinsed, and then processed for histology. Their results indicate that morphological detail and staining characteristics were identical for the two groups of samples. An example of their findings is presented in Figure 2. In addition to excellent staining and preservation of morphological detail, many immunohistological stains performed equally well in the RNAlater solution–preserved samples, suggesting preservation in RNAlater solution caused no damage to cellular epitopes.

Figure 2. Histology of RNAlater solution–preserved tissue. RNAlater solution–preserved samples are suitable for histology and provide excellent morphological detail. Sections made from RNAlater-preserved material were indistinguishable from slides made from untreated samples when examined for standard histological criteria. (A). H&E stained, frozen section of human skin preserved for one week in RNAlater solution prior to processing. (B). Stained as above but formalin-fixed, paraffin-embedded section of human skin preserved for one week in RNAlater solution prior to processing.

This convenient and inexpensive product preserves the integrity of your precious RNA and saves you the time and trouble of grinding frozen tissue in liquid nitrogen. RNAlater solution is economical and can be stored at room temperature.