We thank Jianhua Ling, Raymond MacDonald, Galvin Swift, Michelle Griffin, Paul Grippo and Satyanarayana Rachagani for their helpful comments, suggestions and sharing of their protocols. This work was supported by grant U01CA111294 and an Idea Development Award from the Ohio State University Intramural Research Program.

1. Preparation
The following practices adhere to the policies set by the Institution&#8217;s Animal Care and Use Committee (IACUC).
<ol>
	<li>It is recommended to isolate no more than 6 mouse pancreases in any given day. Have all surgical instruments clean and autoclaved, one set per animal.</li>
	<li>Label all microcentrifuge tubes. Four 2 ml tubes per animal.</li>
	<li>Place 8 ml of lysis reagent in 50 ml centrifuge tubes on ice. Note: While the purification kit comes with a guanidine thio...

<ol>
	<li>Chen, C., Ridzon, D. A., Broomer, A. J., Zhou, Z., Lee, D. H., Nguyen, J. T., Barbisin, M., Xu, N. L., Mahuvakar, V. R., Andersen, M. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+quantification+of+microRNAs+by+stem-loop+RT-PCR.">Real-time quantification of microRNAs by stem-loop RT-PCR.</a> Nucleic Acids Res. 33, e179 (2005).</li><li>Chirgwin, J. M., Przybyla, A. E., MacDonald, R. J., Rutter, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+biologically+active+ribonucleic+acid+from+sources+enriched+in+ribonuclease.">Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease.</a> Biochemistry. 18, 5294-5299 (1979).</li><li>Chomczynski, P., Sacchi, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-step+method+of+RNA+isolation+by+acid+guanidinium+thiocyanate-phenol-chloroform+extraction.">Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction.</a> Anal Biochem. 162, 156-159 (1987).</li><li>Griffin, M., Abu-El-Haija, M., Abu-El-Haija, M., Rokhlina, T., Uc, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simplified+and+versatile+method+for+isolation+of+high-quality+RNA+from+pancreas.">Simplified and versatile method for isolation of high-quality RNA from pancreas.</a> Biotechniques. 52, 332-334 (2012).</li><li>Iyer, V. R., Eisen, M. B., Ross, D. T., Schuler, G., Moore, T., Lee, J. C., Trent, J. M., Staudt, L. M., Hudson Jr, J., Boguski, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+transcriptional+program+in+the+response+of+human+fibroblasts+to+serum.">The transcriptional program in the response of human fibroblasts to serum.</a> Science. 283, 83-87 (1999).</li><li>Lenstra, J. A., Beintema, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+amino+acid+sequence+of+mouse+pancreatic+ribonuclease.+Extremely+rapid+evolutionary+rates+of+the+myomorph+rodent+ribonucleases.">The amino acid sequence of mouse pancreatic ribonuclease. Extremely rapid evolutionary rates of the myomorph rodent ribonucleases.</a> European journal of biochemistry FEBS. 98, 399-408 (1979).</li><li>Mullin, A. E., Soukatcheva, G., Verchere, C. B., Chantler, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+in+situ+ductal+perfusion+to+facilitate+isolation+of+high-quality+RNA+from+mouse+pancreas.">Application of in situ ductal perfusion to facilitate isolation of high-quality RNA from mouse pancreas.</a> Biotechniques. 40, 617-621 (2006).</li><li>Rio, D. C., Ares, M., Hannon, G. J., Nilsen, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> RNA A Laboratory Manual. , (2011).</li><li>Streit, S., Michalski, C. W., Erkan, M., Kleeff, J., Friess, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Northern+blot+analysis+for+detection+and+quantification+of+RNA+in+pancreatic+cancer+cells+and+tissues.">Northern blot analysis for detection and quantification of RNA in pancreatic cancer cells and tissues.</a> Nat Protoc. 4, 37-43 (2009).</li><li>Zmuda, E. J., Powell, C. A., Hai, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+murine+islet+isolation+and+subcapsular+kidney+transplantation.">A method for murine islet isolation and subcapsular kidney transplantation.</a> Journal of Visualized Experiments JoVE. , (2011).</li></ol>

Isolating RNA from tissues that are ribonuclease rich represents a great challenge for molecular biology experiments. Various reagents and kits are commercially available that are primarily based upon the phenol guanidine thiocyanate method of RNA extraction. Guanidine thiocyanate denatures protein and thus reduces the activity of ribonuclease. However, the sheer magnitude of ribonuclease in pancreas requires additional modifications to standard protocols of RNA isolation. A protocol is reported here that is based on the...

Isolation of RNA with high integrity is required for routine molecular biology experiments such as northern blotting 9, qRT-PCR 1 or gene expression profiling 5. Most contemporary methods of RNA isolation are based upon modifications of the guanidine thiocyanate protocols 2, 3. Guanidine thiocyanate is a strong protein denaturant and will effectively disrupt the activity of ribonuclease under most conditions. The popular method of Chomczynski and Sacchi 3 combined phenol to the guanidine thiocyanate lysis solution, reducing the isolation time to about 4 hr. Many commercially-available RNA extraction reagents are based upon the Chomczynski and Sacchi method 3.
Ribonuclease rich tissues such as human or mouse pancreas presents an additional challenge for isolating RNA. Mouse pancreas may contain up to 75 mg of ribonuclease 6 some of which will be released during disruption of the pancreatic tissue resulting in tissue autolysis. Modifications of the guanidine thiocyanate protocols have been successfully used to isolate RNA from pancreas with high integrity 2, 4, 7, 10. Infusion of RNA stabilization reagent into mouse pancreas facilitated isolation of RNA with high integrity 4, 7, 10, however infusion of solutions into the pancreas requires great skill, may require specialized instruments such as a dissecting microscope and disrupting tissue architecture during the procedure may result in cell lysis. Perfusing tissue with RNA stabilization reagent might interfere with other applications including protein isolation and histological staining. Furthermore, this technique is not suitable for isolating RNA from human pancreas. Other protocols require the preparation of specific solutions by the investigator 2.
We report a protocol to isolate RNA with high integrity from mouse pancreas. The protocol uses elements of previously published methods and is largely based upon the standard phenol/guanidine thiocyanate-based lysis reagent protocols. It does not require the preparation of specialized solutions nor does it require infusion of reagents into the pancreas. Critical steps for successful RNA isolation include a high phenol/guanidine-based lysis reagent to tissue ratio, removal of undigested tissue prior to phase separation and inclusion of a ribonuclease inhibitor to the resulting RNA solution. Using these and other modifications, we typically isolate RNA with RIN greater than 7 to be used for routine gene expression analysis.

<table border="0" cellpadding="0" cellspacing="0" width="788">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Name of Reagent/ Equipment</td>
			<td style="width:93px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:360px;">Comments/Description</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Power Gen 500&#160;</td>
			<td style="width:93px;">Fisher Scientific</td>
			<td style="width:119px;">14-261-03&#160;</td>
			<td>Homogenizer</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">5424R</td>
			<td style="width:93px;">Eppendorf</td>
			<td style="width:119px;"></td>
			<td>Refrigerated microcentifuge</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Trizol reagent</td>
			<td style="width:93px;">Invitrogen</td>
			<td style="width:119px;">15596018</td>
			<td>Lysis reagent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Student Vannas spring scissors</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">91500-09&#160;</td>
			<td>use to cut pancreas from attached tissues</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Surgical scissors, 6 inch</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">08-951-20</td>
			<td>use to cut scin of mouse</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Blunt end forceps</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">1381239</td>
			<td>use to hold pancreas while dissecting</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Isoflurane USP</td>
			<td style="width:93px;">Abbott Labs</td>
			<td style="width:119px;">4/8/5210</td>
			<td>Anesthetic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rnase out (40 U/&#181;l)</td>
			<td style="width:93px;">Invitrogen</td>
			<td style="width:119px;">10777-019</td>
			<td>Rnase inhbitor</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:216px;">Rnase Away</td>
			<td style="width:93px;">Ambion</td>
			<td style="width:119px;">10328-011</td>
			<td>General Rnase inactivator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">HPLC grade water</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">W5-4</td>
			<td>For washing homogenizer blades</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Molecular Biology grade water</td>
			<td style="width:93px;">Hyclone</td>
			<td style="width:119px;">SH30538.03</td>
			<td>Elution of RNA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">miRNeasy Mini kit</td>
			<td style="width:93px;">Qiagen</td>
			<td style="width:119px;">217004</td>
			<td>Purification Kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">2 ml microcentrifuge tubes, certified Rnase Dnase free</td>
			<td style="width:93px;">USA Scientific Plastics</td>
			<td style="width:119px;">1620-2700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">15 ml centrifuge tubes</td>
			<td style="width:93px;">Falcon</td>
			<td style="width:119px;">352099</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">70% ethanol</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">100% ethanol</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">200 ul pipet tips</td>
			<td style="width:93px;">Rainin</td>
			<td style="width:119px;">GPL200F</td>
			<td>For cleaning homogenizer blades</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Chloroform</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">BP1145-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Nanodrop</td>
			<td style="width:93px;">Thermo</td>
			<td style="width:119px;">ND-1000</td>
			<td>Spectrophotometer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Bioanalyzer</td>
			<td style="width:93px;">Agilent</td>
			<td style="width:119px;"></td>
			<td>Capillary electrophoresis analyzer to measue RNA integrity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">RNAlater</td>
			<td style="width:93px;">Ambion</td>
			<td style="width:119px;"></td>
			<td>RNA Stabilization Reagent&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">RNeasy&#160;spin columns&#160;</td>
			<td style="width:93px;">Qiagen</td>
			<td style="width:119px;"></td>
			<td>&#160;spin columns&#160;as a part of the miRNeasy Mini kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mice</td>
			<td style="width:93px;">Chales River</td>
			<td style="width:119px;">strain C57BL/6</td>
			<td style="width:360px;">Their age ranged from 4 to 12 months.&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mice&#160;</td>
			<td style="width:93px;">Jackson Lab</td>
			<td style="width:119px;">strain 129</td>
			<td style="width:360px;">Their age ranged from 4 to 12 months.&#160;&#160;</td>
		</tr>
	</tbody>
</table>

rna isolation from mouse pancreas: a ribonuclease-rich tissue

Isolation of high-quality RNA from ribonuclease-rich tissue such as mouse pancreas presents a challenge. As a primary function of the pancreas is to aid in digestion, mouse pancreas may contain as much a 75 mg of ribonuclease. We report modifications of standard phenol/guanidine thiocyanate lysis reagent protocols to isolate RNA from mouse pancreas. Guanidine thiocyanate is a strong protein denaturant and will effectively disrupt the activity of ribonuclease under most conditions. However, critical modifications to standard protocols are necessary to successfully isolate RNA from ribonuclease-rich tissues. Key steps include a high lysis reagent to tissue ratio, removal of undigested tissue prior to phase separation and inclusion of a ribonuclease inhibitor to the RNA solution. Using these and other modifications, we routinely isolate RNA with RNA Integrity Number (RIN) greater than 7. The isolated RNA is of suitable quality for routine gene expression analysis. Adaptation of this protocol to isolate RNA from ribonuclease rich tissues besides the pancreas should be readily achievable.

The total RNA yield from 1 ml of lysis homogenate is 20-40 &#181;g. OD 260/280 ratios are typically around 2.0 and the RIN are consistently greater than 7.0. If the RIN is &#8804;6, the isolation will need to be repeated. Occasionally, a RIN that is higher than 8.0 is achieved.
The two most commonly used methods of euthanizing mice prior to removal of the pancreas are CO2 asphyxiation or inhalation of isoflurane. Both techniques are followed by cervical dislocation. Since it is poss...

Watch this Scientific Journal Video about RNA Isolation from Mouse Pancreas: A Ribonuclease-rich Tissue at JoVE.com

RNA Isolation from Mouse Pancreas: A Ribonuclease-rich Tissue

We report a procedure to isolate RNA with high integrity from the ribonuclease rich mouse pancreas.

Isolation of high-quality RNA from ribonuclease-rich tissue such as mouse pancreas presents a challenge.  As a primary function of the pancreas is to aid ...

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27.3K visualizações.  The Ohio State University. We report a procedure to isolate RNA with high integrity from the ribonuclease rich mouse pancreas.