Stability of RNA isolated from post-mortem tissues of Atlantic salmon (Salmo salar L.)
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Studies of post-mortem interval on the stability of RNA from a number of various mammals have shown RNA to be stable for between 24 and 48 h following death. As yet there have been no studies looking at RNA stability in post-mortem tissues of poikilothermic fish. Brain, kidney, liver and muscle were collected from Atlantic salmon (Salmo salar) parr and samples of each tissue were placed into RNAlater™ after 0–24 h post-mortem storage at room temperature. Electrophoretic analysis of the total RNA showed degradation of ribosomal RNA only in muscle from 8 h onwards. Probing of northern blots with β-actin showed that, in the brain, β-actin mRNA was stable for 24 h post-mortem but degradation of mRNA was observed after 8 h with the kidney and liver and after 4 h with the muscle. Expression of the weakly expressed thyroid hormone receptor β (TRβ) was detected by reverse transcriptase polymerase chain reaction (RT-PCR) in all tissues up to 24 h post-mortem although a reduction in PCR product was observed after 8 h with muscle and 24 h with kidney. Analysis with an Agilent 2100 Bioanalyzer showed that the RNA integrity number (RIN) of brain total RNA remained constant for 8 h post-mortem with only a small fall at 24 h post-mortem. The RINs of the remaining tissues indicated degradation at 8 h post-mortem with kidney and muscle and at 24 hours post-mortem with liver. Taken together these findings show that degradation of Atlantic salmon RNA is tissue dependent but stable for at least one hour post-mortem.
KeywordsBrain Degradation Kidney Liver Muscle Post-mortem interval RNA stability
RNA integrity number
Thyroid hormone receptor β
The authors would like to thank Dr Sarah Rogers for supplying the Atlantic salmon β-actin clone and Dr Marco Campinho for his technical assistance. This work was supported by the Biotechnology and Biological Sciences Research Council under grant no. 72/EGA17676.