The authors acknowledge the contribution of Hammond Bay Biological Station, Great Lakes Science Center, U.S. Geological Survey. We also thank Dr. Melinda Frame at the Center for Advanced Microscopy at Michigan State University for her technical support in laser scanning confocal microscopy. This study is supported by grants from the Great Lakes Fishery Commission to YWCD and WML.

1. Solution Preparation
<ol>
	<li>Make 1 L 10x 0.1 M phosphate buffer saline (PBS, pH 7.4): Weigh 26.2 g sodium phosphate (monobasic), 115 g sodium phosphate (dibasic), and 87.66 g NaCl. Dissolve in about 800 ml distilled H2O, adjust pH, and bring the volume up to 1 L with distilled H2O.
	<ol>
		<li>Make 1 L 0.1 M phosphate buffer saline (pH 7.4): Take 100 ml 10x PBS, and add 900 ml distilled H2O.</li>
		<li>Make 1 L 0.1 M phosphate buffer saline (pH 7.4) with 0.1% Triton X-100: Take 10...

<ol>
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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+description+of+the+stages+in+the+metamorphosis+of+the+anadromous+sea+lamprey,+Petromyzon+marinus+L.">A description of the stages in the metamorphosis of the anadromous sea lamprey, Petromyzon marinus L.</a> Can. J. Zool. 57, 1808-1817 (1979).</li><li>Boomer, L. A., 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=Cholangiocyte+apoptosis+is+an+early+event+during+induced+metamorphosis+in+the+sea+lamprey,+Petromyzon+marinus+L.">Cholangiocyte apoptosis is an early event during induced metamorphosis in the sea lamprey, Petromyzon marinus L.</a> J. Pediatr. Surg. 45, 114-120 (2010).</li><li>Kasai, M., Suzuki, H., Ohashi, E., Ohi, R., Chiba, T., Okamoto, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technique+and+results+of+operative+management+of+biliary+atresia.">Technique and results of operative management of biliary atresia.</a> World J. Surg. 2, 571-580 (1978).</li><li>Suzuki, T., Hashimoto, T., Kondo, S., Sato, Y., Hussein, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluating+patients&#8217;+outcome+post-Kasai+operation:+a+19-year+experience+with+modification+of+the+hepatic+portoenterostomy+and+applying+a+novel+steroid+therapy+regimen.">Evaluating patients&#8217; outcome post-Kasai operation: a 19-year experience with modification of the hepatic portoenterostomy and applying a novel steroid therapy regimen.</a> Pediatr. Surg. Int. 26, 825-830 (2010).</li><li>Hartley, J. L., Davenport, M., Kelly, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biliary+atresia.">Biliary atresia.</a> Lancet. 374, 1704-1713 (2009).</li><li>Morecki, R., Glaser, J. H., Cho, S., Balistreri, W. F., Horwitz, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biliary+atresia+and+reovirus+type+3+infection.">Biliary atresia and reovirus type 3 infection.</a> New Engl. J. Med. 307, 481-484 (1982).</li><li>Shimadera, S., Iwai, N., Deguchi, E., Kimura, O., Fumino, S., Yokoyama, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+inv+mouse+as+an+experimental+model+of+biliary+atresia.">The inv mouse as an experimental model of biliary atresia.</a> J. Pediatr. Surg. 42, 1555-1560 (2007).</li><li>Sidon, E. W., Youson, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphological+changes+in+the+liver+of+the+sea+lamprey,+Petromyzon+marinus+L.,+during+metamorphosis:+I.+Atresia+of+the+bile+ducts.">Morphological changes in the liver of the sea lamprey, Petromyzon marinus L., during metamorphosis: I. Atresia of the bile ducts.</a> J. Morphol. 177, 109-124 (1983).</li><li>Yeh, C. -. Y., Chung-Davidson, Y. -. W., Wang, H., Li, K., Li, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intestinal+synthesis+and+secretion+of+bile+salts+as+an+adaptation+to+developmental+biliary+atresia+in+the+sea+lamprey.">Intestinal synthesis and secretion of bile salts as an adaptation to developmental biliary atresia in the sea lamprey.</a> Proc. Nat. Acad. Sci. 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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastructural+features+of+degeneration+of+the+gallbladder+during+lamprey+biliary+atresia.">Ultrastructural features of degeneration of the gallbladder during lamprey biliary atresia.</a> Tissue and Cell. 22, 477-492 (1990).</li><li>Morii, M., 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=Onset+of+apoptosis+in+the+cystic+duct+during+metamorphosis+of+a+Japanese+lamprey,+Lethenteron+reissneri.">Onset of apoptosis in the cystic duct during metamorphosis of a Japanese lamprey, Lethenteron reissneri.</a> Anat. Rec. 293, 1155-1166 (2010).</li></ol>

This protocol is modified from a new method called &#8220;CLARITY&#8221;12, which crosslinks intact tissue with polyacrylamide to form a nanoporous hydrogel, and then strips away the plasma membrane of the tissue to achieve optical transparency and macromolecular permeability. &#8220;CLARITY&#8221; allows intact-tissue imaging of long-range projection and local circuit wiring in the nervous system. This new method can be used to visualize the entire biliary system in sea lamprey liver during metamorphosis. It ...

Sea lamprey develop through three distinct life stages1,2. Larval sea lamprey (L) spend most time in burrows as benthic filter feeders. After going through seven metamorphic stages of dramatic changes in external morphology and reorganization in internal organs3, the resulting juveniles (JV) enter a parasitic stage during which they feed on blood and tissue fluids from host fish, increasing the body mass more than 100 times. After 1.0 to 1.5 years feeding on the host fish in the ocean or large lakes, adults cease feeding during the early spring and migrate into rivers to spawn and then die1,2.

During metamorphosis, the sea lamprey liver loses the gall bladder and the entire biliary tree, an evolutionary mutant phenotype that mimics the human infant disease biliary atresia. Infant biliary atresia is a rare pediatric liver disease with severe medical complications4,5,6,7,8,9,10, however the pathogenesis and etiology of biliary atresia are largely unknown4. Patients with biliary atresia die within two years after birth unless surgical intervention (Kasai procedure) is performed5. Subsequently, these patients require extensive clinical management and often liver transplantation&#160;6. Many theories of biliary atresia etiopathogenesis have been proposed, such as viral infection, congenital malformation, autoimmune disease, and toxic insult. However, the contribution of each to the development of biliary atresia remains inconclusive7,8,9,10.

Unlike infants that suffer pathological biliary atresia, sea lamprey undergo developmentally programmed biliary atresia without extensive necroinflammation, fibrosis or cirrhosis10. The animals may suffer transient cholestasis during this process10, but adapt to this developmental condition via de novo synthesis and secretion of bile salts in the intestine after developmental biliary atresia, in addition to known mechanisms such as reduction of bile salt synthesis in liver11. This developmental process in sea lamprey provides the only known opportunity to examine the progression of biliary atresia.

A newly-developed method called &#8220;CLARITY&#8221; enables high-resolution imaging in complex mammalian nervous systems by transforming intact tissue into an optically transparent nanoporous hydrogel12. Using sea lamprey liver and a modified CLARITY protocol, intact-tissue imaging of biliary degeneration can be documented throughout liver metamorphosis.

<table border="0" cellpadding="0" cellspacing="0" width="702">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">40% acrylamide&#160;</td>
			<td style="width:200px;">Bio-Rad</td>
			<td style="width:119px;">161-0140</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2% bis-acrylamide&#160;</td>
			<td>Bio-Rad</td>
			<td>161-0142</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TEMED</td>
			<td>Bio-Rad</td>
			<td>161-0800</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ammonium persulfate&#160;</td>
			<td>Sigma</td>
			<td>A3678-25G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">boric acid</td>
			<td>Sigma</td>
			<td>B7901-1KG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">saponin&#160;</td>
			<td>Sigma</td>
			<td>47036</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">sodium dodecyl sulfate&#160;</td>
			<td>Sigma</td>
			<td style="width:119px;">L337-500G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">sodium phosphate (monobasic)</td>
			<td>Sigma</td>
			<td>04269-1KG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">sodium phosphate (dibasic)</td>
			<td>Sigma</td>
			<td>S5136-1KG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Triton X-100</td>
			<td>Sigma</td>
			<td>X100-500ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">glycerol&#160;</td>
			<td>Sigma</td>
			<td>G9012-500ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">16% paraformaldehyde&#160;</td>
			<td>Electron Microscopy Sciences</td>
			<td>15710-S</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NaOH pellets&#160;</td>
			<td>EMD</td>
			<td>SX0590-3</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">15 ml centrifuge tubes</td>
			<td style="width:200px;">Any brand</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">dissecting tools&#160;</td>
			<td style="width:200px;">Any brand</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

a new clarification method to visualize biliary degeneration during liver metamorphosis in sea lamprey (petromyzon marinus)

Biliary atresia is a rare disease of infancy, with an estimated 1 in 15,000 frequency in the southeast United States, but more common in East Asian countries, with a reported frequency of 1 in 5,000 in Taiwan. Although much is known about the management of biliary atresia, its pathogenesis is still elusive. The sea lamprey (Petromyzon marinus) provides a unique opportunity to examine the mechanism and progression of biliary degeneration. Sea lamprey develop through three distinct life stages: larval, parasitic, and adult. During the transition from larvae to parasitic juvenile, sea lamprey undergo metamorphosis with dramatic reorganization and remodeling in external morphology and internal organs. In the liver, the entire biliary system is lost, including the gall bladder and the biliary tree. A newly-developed method called &#8220;CLARITY&#8221; was modified to clarify the entire liver and the junction with the intestine in metamorphic sea lamprey. The process of biliary degeneration was visualized and discerned during sea lamprey metamorphosis by using laser scanning confocal microscopy. This method provides a powerful tool to study biliary atresia in a unique animal model.

Several important developmental events occur in the hepatobiliary system during sea lamprey metamorphosis. The bile duct and the gall bladder undergo apoptosis and degenerate (Figure 1). Combining the modified clarification method and staining with liver cell marker cytokeratin 19 (CK19, present in both cholangiocytes and hepatocytes before and after metamorphosis13) and anti-apoptotic marker Bcl2 using confocal microscopy, the entire biliary system was captured along the Z-axis (Figur...

Watch this Scientific Journal Video about A New Clarification Method to Visualize Biliary Degeneration During Liver Metamorphosis in Sea Lamprey Petromyzon marinus at JoVE.com

A New Clarification Method to Visualize Biliary Degeneration During Liver Metamorphosis in Sea Lamprey Petromyzon marinus

Sea lamprey lose the gall bladder and bile ducts during metamorphosis, a process similar to human biliary atresia. A new fixation and clarification method (CLARITY) was modified to visualize the entire biliary tree using laser scanning confocal microscopy. This method provides a powerful tool to study biliary degeneration.

A New Clarification Method to Visualize Biliary Degeneration During Liver Metamorphosis in Sea Lamprey (Petromyzon marinus)

Biliary atresia is a rare disease of infancy, with an estimated 1 in 15,000 frequency in the southeast United States, but more common in East Asian ...

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13.7K ビュー.  Michigan State University. 海のヤツメウナギは変態期胆嚢や胆管、人間の胆道閉鎖症と同様のプロセスを失う。新しい固定および清澄法（CLARITY）はレーザー走査共焦点顕微鏡を用いて全体胆ツリーを視覚化するために変更されました。この方法では、胆管の変性を研究するための強力なツールが用意されています。 