The Grosshadern Hospital Tissue Bank is a repository of clinically annotated surgical
remnant tissues that can be accessed by researchers for basic and translational research.
An important technology for elucidating molecular mechanisms of diseases is reverse
transcription polymerase chain reaction (RT-PCR). However, accuracy of information
garnered by RT-PCR is highly dependent on tissue quality. Thus, this study aimed to
determine if tissues with longer processing times are suitable for RT-PCR studies
and if processing temperatures or storage in RNAlater would help maintain RNA quality.
Liver samples were collected over a time course; during surgery before blood arrest,
after surgery, post sampling by the pathology department (Tpp), 3 hours after Tpp
and 1 day after Tpp. For the last 2 time-points, samples were kept at either room
temperature (RT) or on ice after Tpp for the duration. All samples were then stored
with or without RNAlater at -80°C. Subsequently, these tissues were assessed for RNA
quality and relative expression levels of 5 genes.
RNA quality was only significantly decreased by 1.9-fold at 1 day after Tpp at RT
with or without RNAlater (P <0.05). However, normalized relative gene expressions
of HPRT, GUSB, MYC, HIF1and GFER were not significantly different when the various
time-points were compared against each other (P >0.05). Also, there were generally
no significant differences between samples stored with or without RNAlater (P >0.05).
In conclusion, it is recommended that samples be kept on ice during processing and
that they be processed as quickly as possible for storage at -80°C. However, when
longer processing times are inevitable, samples can still be used for RT-PCR studies,
provided that relative expression of the gene of interest is proven not to be affected.
Thus, this study shows that samples with longer processing times can still be banked
and this relaxed criterion will increase accrual of samples to the tissue bank.
RNA stability - RT-PCR - gene expression - tissue bank
