Table 1.

A summary of published protocols for pancreatic RNA extraction.

No.	Study	Source	Treatment with RNAlater	Tissue Preservation	Extraction Method	RNA Yield	Absorbance Ratio A260/A280 nm	RNA Integrity Assessment
1	Augereau et al., 2016 [3]	Mice	A quarter of the pancreas was removed and injected with 500 µL RNAlater.	Small pieces of the injected pancreas were placed in 350 µL RNAlater, snap-frozen in liquid nitrogen, and stored at −80 °C for 24 h.	Guanidium thiocyanate-phenol extraction using TriPure isolation reagent.	10–15 mg	1.85 ± 0.01	RIN = 8.9 ± 0.38 using the Agilent 2100 bioanalyzer system.
2	Mullin et al., 2006 [4]	Mice	1–2 mL RNAlater was injected through the common bile duct after clamping the duodenum at the sphincter of Oddi.	The excised part of the pancreas (30 mg) was placed in 5 volumes of RNAlater on ice and processed immediately for extraction.	Guanidium thiocyanate-phenol extraction using TRIzol reagent.	4.97 ± 1.92 µg/mL	1.41 ± 0.06	Clear bands of the ribosomal 28S and 18S RNA subunits were detected on 0.8% agarose gel.
3	Kiba et al., 2007 [5]	Rats	The pancreas was snap-frozen in liquid nitrogen and placed in 10 volumes of RNAlater-ICE.	The tissue was processed either immediately, 30 min later, after overnight at 4 °C, or following storage at −80 °C for 1–7 d.	Qiagen RNeasy Mini Kit	0.5–1 µg/mL	-	Clear bands of the ribosomal 28S and 18S RNA subunits were determined by laser densitometry.
4	Griffin et al., 2012 [6]	Mice and piglets	Half the pancreas was excised and perfused with RNAlater at multiple sites.	The perfused pancreas was cut into small pieces, snap-frozen in liquid nitrogen, and stored at −80 °C.	Qiagen RNeasy lipid tissue Mini Kit	Mice: 697 ± 203 ng/µL Piglets: 115 ± 17 ng/µL	-	Average RIN: mice around 6.5 piglets around 8
5	Dastgheib et al., 2014 [7]	Rats	The pancreas was immersed in 1 mL RNAlater and cut into small pieces (20–30 mg).	The tissue was processed immediately, 30 min later, after overnight at 4 °C, or following storage at −80 °C for 1–7 days.	Several methods: RNX-plus solution, TriPure, and Qiagen RNeasy micro kits	-	-	Clear bands of the ribosomal 28S and 18S RNA subunits were detected on denaturing agarose gel from samples immersed in RNAlater for 24 h at −80 °C and extracted by TriPure reagent; the cDNA quality was confirmed with (β-actin) amplification by RT-PCR.
6	Azevedo-Pouly et al., 2014 [8]	Mice	This study did not use RNAlater for improving RNA integrity but, rather, recommendations and modification steps in the extraction from the RNeasy Mini Kit that were used in our optimized extraction protocol.			20–40 µg	Approx. 2.0	RIN = 7.4 ± 0.20 using the Agilent 2100 Bioanalyzer System and confirmed with qRT-PCR for three housekeeping genes.

RNAlater (Qiagen, Hilden, Germany); TriPure isolation reagent (Roche, Basel, Switzerland).