Name: a simple high efficiency protocol for pancreatic islet isolation from mice
Uploaded: 2019-08-30T12:30:00
Description: Watch this Scientific Journal Video about A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice at JoVE.com

We are extremely grateful to Ms. Jennifer Munguia for her artistic illustration of the schematic diagram. We thank Mr. Michael R. Honig at Houston&rsquo;s Community Public Radio Station KPFT for his editorial assistance. This study was supported by American Diabetes Association #1-15-BS-177 (YS), and NIH R56DK118334/R01DK118334 (YS). This work was also supported by the USDA National Institute of Food and Agriculture, Hatch project 1010840 (YS) and R01 DK095118 (SG).

All methods described here have been approved by the Animal Care and Use Committee (ACUC) of Texas A&#38;M University. The surgical tools need is shown in Figure 1 and the schematic diagram of the procedure is shown in Figure 2.
1. Solutions
<ol>
	<li>Prepare Hank&#8217;s Balanced Salt Solution (HBSS) by adding 100 mL of 10X HBSS (from stock) to 900 mL of distilled water to make 1 L HBSS (1X).</li>
	<li>Prepare STOP solution (must b...

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+protocol+for+islet+isolation+from+mouse+pancreas.">A protocol for islet isolation from mouse pancreas.</a> Nature Protocols. 4 (11), 1649-1652 (2009).</li><li>Neuman, J. C., Truchan, N. A., Joseph, J. W., Kimple, M. E. <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+mouse+pancreatic+islet+isolation+and+intracellular+cAMP+determination.">A method for mouse pancreatic islet isolation and intracellular cAMP determination.</a> Journal of Visualized Experiments : JoVE. (88), e50374 (2014).</li><li>Scharp, D. W., Lacy, P. E., Finke, E., Olack, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-temperature+culture+of+human+islets+isolated+by+the+distention+method+and+purified+with+Ficoll+or+Percoll+gradients.">Low-temperature culture of human islets isolated by the distention method and purified with Ficoll or Percoll gradients.</a> Surgery. 107 (5), e50374 (1987).</li><li>Salvalaggio, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Islet+filtration:+a+simple+and+rapid+new+purification+procedure+that+avoids+ficoll+and+improves+islet+mass+and+function.">Islet filtration: a simple and rapid new purification procedure that avoids ficoll and improves islet mass and function.</a> Transplantation. 74 (66), 877-879 (2002).</li><li>Saliba, Y., Bakhos, J. J., Itani, T., Fares, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+optimized+protocol+for+purification+of+functional+islets+of+Langerhans.">An optimized protocol for purification of functional islets of Langerhans.</a> Laboratory Investigation. 97 (1), 70-83 (2017).</li><li>Pradhan, G., 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=Obestatin+stimulates+glucose-induced+insulin+secretion+through+ghrelin+receptor+GHS-R.">Obestatin stimulates glucose-induced insulin secretion through ghrelin receptor GHS-R.</a> Scientific Reports. 7 (1), 979 (2017).</li><li>Shapiro, A. M. J., Hao, E., Rajotte, R. V., Kneteman, N. 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This protocol includes collagenase perfusion and digestion, followed by purification of islets. The most critical steps of this protocol are effective injection and complete perfusion of the pancreas1,4,7. The delivery method of this protocol allows the enzyme to traverse the anatomical routes to better digest the exocrine tissue surrounding the islets1. In addition, this technique is well suited for comp...

There are two common methods in the literature for pancreatic islet isolation. One requires excising the pancreas and dicing it into small pieces using surgical scissors, and then digesting it in a collagenase solution1,2,3. Another more precise method is to use the network of ducts present in the pancreas to introduce digestive enzyme. The following sites have been used for digestive enzyme injection: the junction of the bile and cystic duct, the gallbladder into the common bile duct, or the common bile duct itself1,4,5. It is known that islets are not evenly distributed in the pancreas; the splenic region contains the most islets6. While the second method using anatomical routes to deliver digestive enzymes allows for a more complete perfusion of the pancreas, including the splenic region, this procedure often requires clamping or suturing of the ampulla of Vater that is technically challenging. In terms of islet purification, multiple density gradients, as well as cell strainers and magnetic retraction have been used to purify the islets3,7. The utilization of these gradients can be time consuming and the Ficoll gradients can result in toxic damage of islets8.
The current protocol is built on the method described by Li et al.7, with additional modifications added based on the experience of ourselves and others1,4. The most critical steps of our protocol are clamping of the common bile duct near the liver end, injecting collagenase P via the ampulla of Vater to digest the exocrine tissue, and then using a shaking water bath to expedite the digestion mechanically1,4,7. Subsequently, a 'STOP' solution is applied to inhibit further digestion of the islets; HBSS is used to wash off the remaining collagenase P and STOP solution. When the Ficoll method was used to purify human islets, yield was reported to be twice the islets with greater functional capability (e.g., insulin secretion) as compared to the use of Percoll gradients9. However, studies have questioned the use of Ficoll gradient due to its toxic effect on the islets1,10. It has been reported that the Histopaque gradient provides optimal purification kinetics for mouse islet isolation, which produces good yield of high quality islets with simpler steps and lower cost1. In our protocol, Histopaque-1077 is used to purify islets from other residual tissue8,11. The harvested islets can be cultured in complete RPMI-1640 media, or directly utilized in RNA/protein quantitation.
Our protocol, using a combination of collagenase P digestion and a single gradient purification step, is simpler than other published protocols. Our method does not require demanding surgical procedures and has just a few simple steps. More importantly, this protocol consistently produces a good yield of high quality functional islets (250-350/mouse) as we reported12.

<table>
	<tbody>
		<tr>
			<td>3 mL syringe</td>
			<td>BD</td>
			<td>309657</td>
			<td>Hoding collagenase P</td>
		</tr>
		<tr>
			<td>Coverglass forceps</td>
			<td>VWR</td>
			<td>82027-396</td>
			<td>Holding skin of mouse to aid incision procedure</td>
		</tr>
		<tr>
			<td>Curved forceps</td>
			<td>Sigma-Aldrich</td>
			<td>Z168696</td>
			<td>Holding tissues during pancreas removal</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Piramal</td>
			<td>B13B16A</td>
			<td>To anaesthetize mice prior surgery</td>
		</tr>
		<tr>
			<td>100 mm petri dishes</td>
			<td>VWR</td>
			<td>30-2041</td>
			<td>Used for islet culture</td>
		</tr>
		<tr>
			<td>30 G. &#189; inch needle</td>
			<td>BD</td>
			<td>305106</td>
			<td>For penetration of Ampulla of vater to deliver Collagenase P - this guage is used as it fits well in most CBDs</td>
		</tr>
		<tr>
			<td>50ml tube</td>
			<td>VWR</td>
			<td>89039-658</td>
			<td>Holding digested pancreatic tissue, collagenase P, and purified islets</td>
		</tr>
		<tr>
			<td>Absorbent pads with waterproof moisture barrier</td>
			<td>VWR</td>
			<td>82020-845</td>
			<td>To absorb blood from syurgical procesdudes</td>
		</tr>
		<tr>
			<td>Centrifuge 5810R with swing bucket and deceleration capability</td>
			<td>Eppendorf</td>
			<td>5811FJ478114</td>
			<td>Use for pelleting tissues, pellet is formed at bottom of conical tube - swing bucket centrifuge is needed. Also the decelaration feature is important to form the gradient layers.</td>
		</tr>
		<tr>
			<td>Collagenase P- 1g</td>
			<td>Roche Diagnostics</td>
			<td>11249002001</td>
			<td>For digestion of exocrine pancreas</td>
		</tr>
		<tr>
			<td>Curved surgical scissors</td>
			<td>Fisher-Scientific</td>
			<td>13-804-21</td>
			<td>For cutting open mouse abdomen</td>
		</tr>
		<tr>
			<td>Dissection microscope</td>
			<td>Olympus</td>
			<td>SZX16</td>
			<td>Used for identification of key anatomical structures to accurately deliver collagenase into pancreas</td>
		</tr>
		<tr>
			<td>Hank&#39;s Balanced Salt Solution 10x</td>
			<td>Corning</td>
			<td>20-023-CV</td>
			<td>Washing cells</td>
		</tr>
		<tr>
			<td>Histopaque-1077</td>
			<td>Sigma</td>
			<td>RNBF5100</td>
			<td>For gradient formation</td>
		</tr>
		<tr>
			<td>Light source</td>
			<td>Leeds</td>
			<td>LR92240</td>
			<td>Enhancing visibility of microscope</td>
		</tr>
		<tr>
			<td>RNaseZap</td>
			<td>Fisher-Scientific</td>
			<td>AM9780</td>
			<td>For removing RNase</td>
		</tr>
		<tr>
			<td>RPMI-1640 Media w/o L-Glutamine</td>
			<td>Corning</td>
			<td>15-040-CV</td>
			<td>Culturing Islets</td>
		</tr>
		<tr>
			<td>Schwartz micro serrefines (Microvascular clamp)</td>
			<td>Fine Science Tools</td>
			<td>18052-01</td>
			<td>Clamping common bile duct and hepatic artery</td>
		</tr>
		<tr>
			<td>Shaking waterbath</td>
			<td>Boekel/Grant</td>
			<td>8R0534008</td>
			<td>Important for mechanical digestion of exocrine tissue</td>
		</tr>
		<tr>
			<td>Small surgical scissors</td>
			<td>VWR</td>
			<td>82027-578</td>
			<td>Cuttitng tissue that atached to pancreas</td>
		</tr>
	</tbody>
</table>

a simple high efficiency protocol for pancreatic islet isolation from mice

Pancreatic islets, also called the Islets of Langerhans, are a cluster of endocrine cells which produces hormones for glucose regulation and other important biological functions. The islets primarily consist of five types of hormone-secreting cells: &#945; cells secrete glucagon, &#946; cells secrete insulin, &#948; cells secrete somatostatin, &#949; cells secrete ghrelin, and PP cells secrete pancreatic polypeptide. Sixty to 80% of the cells in the islets are &#946; cells, which are the most important cell population to study insulin secretion. Pancreatic islets are a crucial model system to study ex vivo insulin secretion. Acquiring high quality islets is of great importance for diabetes research. Most islet isolation procedures require technically difficult to access site of collagenase injection, harsh and complex digestion procedures, and multiple density gradient purification steps. This paper features a simple high yield mouse islet isolation method with detailed descriptions and realistic demonstrations, showing the following specific steps: 1) injection of collagenase P at the ampulla of Vater, a small area joining the pancreatic duct and the common bile duct, 2) enzymatic digestion and mechanical separation of the exocrine pancreas, and 3) a single gradient purification step. The advantages of this method are the injection of digestive enzyme using the more accessible ampulla of Vater, more complete digestion using combination of enzymatic and mechanical approaches, and a simpler single gradient purification step. This protocol produces approximately 250&#8212;350 islets per mouse; and islets are suitable for various ex vivo studies. Possible caveats of this procedure are potentially damaged islets due to enzymatic digestion and/or prolonged gradient incubation, all of which can be largely avoided by careful ad justification of incubation time.

Proper completion of this procedure requires some understanding of mouse anatomy in the abdominal cavity. This allows for proper identification of the ampulla of Vater and clamping of the common bile duct. The entire procedure normally takes 1&#8211;2 h. It is more efficient to isolate islets from 4&#8211;6 mice at the same time, so several samples can be centrifuged together. The time for islet-picking varies, depending on the number of islets and the efficiency of digestion; it may take roughly an hour to pick 250&#821...

Watch this Scientific Journal Video about A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice at JoVE.com

A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice

This islet isolation protocol described a novel route of collagenase injection to digest the exocrine tissue and a simplified gradient procedure to purify the islets from mice. It involves enzymatic digestion, gradient separation/purification, and islet hand-picking. Successful isolation can yield 250&#8211;350 high quality and fully functional islets per mouse.

Pancreatic islets, also called the Islets of Langerhans, are a cluster of endocrine cells which produces hormones for glucose regulation and other ...

This protocol requires the use of a single density gradient making it significantly less labor intensive and more cost effective compared to more complex conventional islet isolation methods. The main advantage of this protocol is that the enzyme is delivered directly to the pancreas resulting in an enhanced tissue digestion and increased islet yield. Begin by taping the limbs of the mouse in the supine position and spraying the body with 70%ethanol.Using coverglass forceps and curved surgical scissors, make an approximately three centimeter horizontal abdominal skin incision and pull open the skin to expose the abdominal wall. Make a three to four centimeter vertical incision on the abdominal peritoneum to fully expose the pancreas and place the mouse under a dissecting microscope. Push the liver lobe superiorly to expose the bile duct which appears as a pale pink tube and gently move the intestines from the right lumbar and iliac region to the right of the abdominal cavity to expose the bile duct and hepatic artery.Use Schwartz micro serrefines to carefully clamp the common bile duct as close to the liver as possible and identify the ampulla of Vater which is located at the duodenal papilla and formed by the union of the pancreatic duct and the common bile duct. Using micro Adson forceps to pull the common bile duct taught, insert a 30 gauge half-inch needle attached to a three milliliter syringe containing three milliliters of freshly prepared collagenase P solution into the ampulla of Vater pushing the needle into the duct parallel to the vessel for about a quarter of the length of the vessel. Once the needle is in place, stabilize the needle with micro Adson forceps and slowly and steadily inject three milliliters of collagenase P solution into the duct.The injection is considered successful if the head, neck, body, and tail regions of the pancreas are fully inflated. Proper entry into the ampulla and cannulation of the common bile duct are critical for a successful digestion harvest. Piercing the ductal walls reduces the efficacy of the isolation.Using curved and micro Adson forceps, carefully pull out the inflated pancreas starting at the spleen and continuing toward the stomach and along the duodenum. Then place the pancreas in a 50 milliliter digestion tube containing three milliliters of ice cold collagenase P solution. To harvest the islets, first use fine surgical scissors to chop the pancreas for three to five seconds before placing the tube in a 37 degree Celsius water bath at 100 to 120 rotations per minute for 12 to 13 minutes.At the end of the incubation, gently shake the tube for about 30 seconds to disrupt the tissue until the solution is homogenous as confirmed by fine sand-like pancreatic tissue particles. As soon as the tissue is digested, place the tube on ice and add 40 milliliters of ice cold stop solution to terminate the enzymatic reaction. After gently disrupting the pellet, spin down the digested tissue in a swinging bucket centrifuge followed by two centrifugations with 20 milliliters of fresh stop solution per wash.After the last wash, resuspend the pellet in 40 milliliters of ice cold HBSS for three additional washes, resuspending the pellet in five milliliters of room temperature density gradient solution after the last wash. Vortex the tube briefly at low speed until the solution is homogenized before adding another five milliliters of room temperature density gradient to the tube. Now use a 10 milliliter pipette to gently and slowly add 10 milliliters of room temperature HBSS to the tube in a drop-wise manner to allow the formation of a gradient and use a swinging bucket centrifuge to isolate the cell populations by density gradient separation.At the end of the centrifugation, use a 10 milliliter pipette pre-wet with cold HBSS to collect five to 10 milliliters of the islet layer between the density gradient and the HBSS. Transfer the islets into a new 50 milliliter tube containing 20 milliliters of fresh ice cold HBSS and collect the cells by centrifugation in a swinging bucket centrifuge. Carefully aspirate all but the last three milliliters of the supernatant without disturbing the pellet and wash the islets at least three more times with 20 milliliters of fresh HBSS per wash.After the last wash, replace the supernatant with four milliliters of 37 degree Celsius RMPI 1640 medium and gently swirl the tube to dislodge the pellet. Immediately pour the islets into a 100 millimeter Petri dish and wash the tube with five milliliters of fresh RPMI 1640 medium to collect any remaining islets pooling the wash with the other islets. Then use a dissection microscope and a 20 microliter pipette tip to pick healthy spherical or oblong golden brown islets with a smooth surface from the Petri dish for transfer into a new Petri dish containing 10 milliliters of complete RPMI 1640 medium.When all of the islets have been collected, place the islets in a sterile incubator at 37 degrees Celsius and 5%carbon dioxide in humidified air overnight. Good healthy islets appear to have a smooth round shape while bad damaged islets exhibit rough edges. Undigested exocrine tissue is translucent in appearance and demonstrates an irregular shape.A proper cannulation and distribution of the collagenase P enzyme can be confirmed by an inflation of the splenic portion of the pancreas. Overnight incubation in low glucose media can prime the islets for a glucose-stimulated insulin secretion assay at the following day allowing insight into the insulin secretory capacity of the islets.

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