The authors thank the Central Animal facility of the University Hospital Aachen for technical support. This work was supported by the German Research Foundation (DFG Ta434/2-1, DFG SFB/TRR 57) and by the Interdisciplinary Center for Clinical Research (IZKF) Aachen. This work was further supported by the Core Facility &#8221;Two-Photon Imaging&#8221;, a Core Facility of the Interdisciplinary Center for Clinical Research (IZKF) Aachen within the Faculty of Medicine at RWTH Aachen University.

NOTE: The experiments were performed in accordance with the German legislation governing animal studies following the &#8216;Guide for the care and use of Laboratory Animals&#8217; (NIH publication, 8th edition, 2011) and the Directive 2010/63/EU on the protection of animals used for scientific purposes (Official Journal of the European Union, 2010). Official permission was granted from the governmental animal care and use office (LANUV Nordrhein-Westfalen, Recklinghausen, Germany).
NOTE: Step...

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The authors disclose no con&#64258;ict of interests.

The aim of our study was to develop a highly standardized, stable and reproducible method for intravital TPLSM imaging of the liver. Intravital imaging in general has given valuable insights into cellular behavior under real life conditions following homing and interaction of different leukocyte populations in development, homeostasis and disease. However, the somewhat challenging anatomical position of the liver, due to which respiratory and peristaltic intestinal movement directly are transmitted to the liver as well a...

The visualization of cells and cellular functions in whole organs or even whole organisms has been of great interest for more than 50 years, including virtually all parts of the body2. Therefore, some early studies already employed intravital imaging of the liver3,4. However, several limitations exist up to date regarding long term stable high-resolution imaging of liver tissue.
Due to the anatomical position of the liver in close contact with the diaphragm and the gastrointestinal tract5, the most common problem for microscopic intravital imaging is movement due to respiration and, to a lesser extent, peristaltic of the intestinal tract6. In comparison to other solid organs, liver surgery is particularly challenging. Due to the dense microvascular structure, surgical manipulation can lead to massive hemorrhagic lesions, impaired microcirculation7 and also activation of resident immune cells such as Kupffer cells8. Therefore, mechanical fixation of the tissue as published elsewhere6,9 is likely to interfere with the intravital microscopy imaging.
In a healthy liver, 10-15% of the total blood volume resides within the liver vasculature, and the organ receives around 25% of the overall cardiac output10, rendering the organ highly susceptible to changes in the circulation (e.g., blood pressure fluctuations). Therefore, disruptions in the hepatic blood flow due to e.g., shear stress, displacement, injury by excessive tissue handling or centralized circulation will lead to artificial alterations in leukocyte migratory behavior, impaired liver oxygenation and therefore further liver damage, affecting liver immune responses as well as organ preservation and overall life time of the animal.
Early microscopic&#160;studies were based on intravital epifluorescence microscopy, but several technical constraints such as photo bleaching and low penetration depth limit the use of this technique for long term liver imaging4,11,12. With the development of multiphoton microscopy in the 1990s, the limitations of photo bleaching or penetration depth were mainly solved, as this new method was technically capable to perform imaging studies in virtually all organs under real life situations13-15. However, the main remaining challenges with respect to liver imaging were: breath movements, autofluorescence of liver tissue, securing unaltered blood flow in the hepatic sinusoids, and especially stable imaging for longer periods of several hr16.
Although several studies addressed the function and migration of various leukocytes in the liver17, e.g., NKT-cells18-20, T cells21,22, liver macrophages23,24 or neutrophils25, long term multiphoton microscopy imaging had not yet been successfully established, a task even more challenging in animals with acute or chronic liver disease due to the existing damage and therefore higher susceptibility to further damage26. However, monitoring migratory behavior and cellular function of leukocytes in the liver in real time allows novel insights in their particular role in liver homeostasis and disease27.
The chemokine receptor CXCR6 is expressed on several lymphocyte subsets, including natural killer (NK) cells, NKT cells and some T cell populations18,28. Prior studies in mice have indicated that CXCR6 and its cognate ligand CXCL16 may control the patrolling of NKT cells on liver sinusoids during homeostasis. Consequently, the use of CXCR6.gfp mice (carrying a knock-in of green fluorescent protein [gfp] in the CXCR6 locus) has been described to investigate the migration of lymphocytes in various organs such as brain29 and also liver18,20, showing increased infiltration of CXCR6.gfp cells upon inflammation.
With the method provided in this study it was possible to follow these processes over a long period of time under stabilized conditions. The intravital multiphoton based procedure allowed imaging that was highly reproducible with minimal perturbation of the animal and the organ; optimized for long-term animal survival by extensive monitoring followed by close control of respiration and circulation; and highly flexible and easy to adopt also to other parenchymal organs such as kidney or spleen.

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			<td height="21" style="height:21px;width:411px;">Anesthetics</td>
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			<td height="21" style="height:21px;width:411px;">Buprenorphine</td>
			<td style="width:263px;">Essex Pharma</td>
			<td style="width:219px;">997.00.00</td>
			<td>Analgeticum, 0.1 mg/kg</td>
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			<td height="21" style="height:21px;width:411px;">Fentanyl</td>
			<td style="width:263px;">Rotex Medica</td>
			<td style="width:219px;">charge: 30819</td>
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			<td height="21" style="height:21px;width:411px;">Fluovac anesthesia system</td>
			<td style="width:263px;">Harvard Apparatus</td>
			<td style="width:219px;">34-1030</td>
			<td></td>
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			<td height="21" style="height:21px;width:411px;">Glucose 5%</td>
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			<td height="21" style="height:21px;">ISOFLO (Isoflurane Vapor) vaporiser</td>
			<td style="width:263px;">Eickemeyer</td>
			<td style="width:219px;">4802885</td>
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			<td height="21" style="height:21px;width:411px;">Isoflurane</td>
			<td style="width:263px;">Forene Abbott</td>
			<td style="width:219px;">B 506</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Isotonic (0.9%) NaCl solution</td>
			<td style="width:263px;">DeltaSelect GmbH</td>
			<td style="width:219px;">PZN 00765145</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Ketamin 10%</td>
			<td style="width:263px;">ceva</td>
			<td style="width:219px;">Charge: 36217/09</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:411px;"></td>
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			<td style="width:219px;"></td>
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		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Xylazin 2%</td>
			<td style="width:263px;">medistar</td>
			<td style="width:219px;">Charge: 04-03-9338/23</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;"></td>
			<td style="width:263px;"></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Consumable supplies</td>
			<td style="width:263px;"></td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">20ml Syringe</td>
			<td style="width:263px;">BD Plastipak</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">250ml Erlenmeyer flask</td>
			<td style="width:263px;">Schott Duran</td>
			<td>21 226 36</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">25mL Beaker 2x</td>
			<td style="width:263px;">Schott Duran</td>
			<td style="width:219px;">50-1150</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">2ml syringe</td>
			<td style="width:263px;">BD Plastipak</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-0 Vicryl suture</td>
			<td style="width:263px;">Ethicon</td>
			<td style="width:219px;">V7980</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Agarose</td>
			<td style="width:263px;">commercially available</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Bepanthen Eye and Nose ointment</td>
			<td style="width:263px;">Bayer Vital GmbH</td>
			<td style="width:219px;">6029009.00.00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Change-A-Tip Deluxe High-Temp Cautery Kit</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">18010-00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Cotton Gauze swabs</td>
			<td style="width:263px;">Fuhrmann GmbH</td>
			<td style="width:219px;">32014</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Cover Slip 24x50mm</td>
			<td style="width:263px;">ROTH</td>
			<td style="width:219px;">1871</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Durapore silk tape</td>
			<td style="width:263px;">3M</td>
			<td style="width:219px;">1538-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Feather disposable scalpel</td>
			<td style="width:263px;">Feather</td>
			<td style="width:219px;">02.001.30.011</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Fine Bore Polythene Tubing 0,58mm ID</td>
			<td style="width:263px;">Smiths medical</td>
			<td style="width:219px;">800/100/200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Histoacryl</td>
			<td style="width:263px;">Braun</td>
			<td style="width:219px;">1050052</td>
			<td>5x 0,5ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Leukoplast</td>
			<td style="width:263px;">BSN Medical Inc.</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Microscope Slides</td>
			<td style="width:263px;">ROTH</td>
			<td style="width:219px;">1879</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Poly-Alcohol Haut&#8230;farblos Antisepticum</td>
			<td style="width:263px;">Antiseptica GmbH</td>
			<td style="width:219px;">72PAH200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Sterican needle 18 G x 1</td>
			<td style="width:263px;">B. Braun</td>
			<td style="width:219px;">304622</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Sterican needle 27 3/4 G x 1</td>
			<td style="width:263px;">B. Braun</td>
			<td style="width:219px;">4657705</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Tissue paper</td>
			<td style="width:263px;">commercially available</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;"></td>
			<td style="width:263px;"></td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Surgical Instruments</td>
			<td style="width:263px;"></td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Amalgam burnisher 3PL</td>
			<td style="width:263px;">Gatz</td>
			<td style="width:219px;">0110?</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Blair retractors (4 pronged (blunt)) x2</td>
			<td style="width:263px;">Storz&#38;Klein</td>
			<td style="width:219px;">S-01134</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dumont No.7 forceps</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">91197-00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Graefe forceps curved x1</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">11151-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Graefe forceps straight x2</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">11050-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Heidemann spatula HD2</td>
			<td style="width:263px;">Stoma</td>
			<td style="width:219px;">2030.00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Needle holder Mathieu</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">12010-14</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Scissor</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">14074-11</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Semken forceps</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">11008-13</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Small surgical scissors curved</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">14029-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Small surgical scissors straight</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">14028-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Standard pattern forceps</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">11000-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vannas spring scissors</td>
			<td style="width:263px;">Fine Science Tools Inc.</td>
			<td style="width:219px;">15000-08</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;"></td>
			<td style="width:263px;"></td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Equipment</td>
			<td style="width:263px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">ECG Trigger Unit</td>
			<td style="width:263px;">Rapid Biomedical</td>
			<td style="width:219px;">3000003686</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">MICROCAPSTAR End-Tidal Carbon Dioxide Analyzer</td>
			<td style="width:263px;">AD Instruments</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Minivent Typ 845</td>
			<td style="width:263px;">Harvard Apparatus</td>
			<td>73-0043</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Multiphoton microscope Trimscope I</td>
			<td style="width:263px;">LaVision</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Perfusor Compact</td>
			<td style="width:263px;">B. Braun</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">PowerLab 8/30 8 channel recorder</td>
			<td style="width:263px;">AD Instruments</td>
			<td style="width:219px;">PL3508</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Temperature controlled heating pad</td>
			<td style="width:263px;">Sygonix</td>
			<td style="width:219px;">26857617</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Temperature sensor</td>
			<td style="width:263px;">comercially available</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:411px;">Temperature controlled System for Microscopes -Cube&#38;Box</td>
			<td style="width:263px;">Life Imaging Services</td>
			<td style="width:219px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

long term intravital multiphoton microscopy imaging of immune cells in healthy and diseased liver using cxcr6.gfp reporter mice

Liver inflammation as a response to injury is a highly dynamic process involving the infiltration of distinct subtypes of leukocytes including monocytes, neutrophils, T cell subsets, B cells, natural killer (NK) and NKT cells. Intravital microscopy of the liver for monitoring immune cell migration is particularly challenging due to the high requirements regarding sample preparation and fixation, optical resolution and long-term animal survival. Yet, the dynamics of inflammatory processes as well as cellular interaction studies could provide critical information to better understand the initiation, progression and regression of inflammatory liver disease. Therefore, a highly sensitive and reliable method was established to study migration and cell-cell-interactions of different immune cells in mouse liver over long periods (about 6 hr) by intravital two-photon laser scanning microscopy (TPLSM) in combination with intensive care monitoring.
The method provided includes a gentle preparation and stable fixation of the liver with minimal perturbation of the organ; long term intravital imaging using multicolor multiphoton microscopy with virtually no photobleaching or phototoxic effects over a time period of up to 6 hr, allowing tracking of specific leukocyte subsets; and stable imaging conditions due to extensive monitoring of mouse vital parameters and stabilization of circulation, temperature and gas exchange.
To investigate lymphocyte migration upon liver inflammation CXCR6.gfp knock-in mice were subjected to intravital liver imaging under baseline conditions and after acute and chronic liver damage induced by intraperitoneal injection(s) of carbon tetrachloride (CCl4).
CXCR6 is a chemokine receptor expressed on lymphocytes, mainly on Natural Killer T (NKT)-, Natural Killer (NK)- and subsets of T lymphocytes such as CD4 T cells but also mucosal associated invariant (MAIT) T cells1. Following the migratory pattern and positioning of CXCR6.gfp+ immune cells allowed a detailed insight into their altered behavior upon liver injury and therefore their potential involvement in disease progression.

To validate our intravital TPLSM approach, we subjected CXCR6gfp/+ mice to intravital TPLSM imaging. Mice were either left untreated as baseline controls or subjected to a single intraperitoneal injection of carbon tetrachloride (CCl4) to induce acute liver damage20.
Video sequences were taken over a time period of 2-5 hr, and cells were traced over time due to their green fluorescence. To show general cellular motility, all tracks that were detected during the...

Watch this Scientific Journal Video about Long Term Intravital Multiphoton Microscopy Imaging of Immune Cells in Healthy and Diseased Liver Using CXCR6.Gfp Reporter Mice at JoVE.com

Long Term Intravital Multiphoton Microscopy Imaging of Immune Cells in Healthy and Diseased Liver Using CXCR6.Gfp Reporter Mice

Stable intravital high-resolution imaging of immune cells in the liver is challenging. Here we provide a highly sensitive and reliable method to study migration and cell-cell-interactions of immune cells in mouse liver over long periods (about 6 hours) by intravital multiphoton laser scanning microscopy in combination with intensive care monitoring.

Liver inflammation as a response to injury is a highly dynamic process involving the infiltration of distinct subtypes of leukocytes including monocytes, ...

long-term-intravital-multiphoton-microscopy-imaging-immune-cells

Research

JoVE Journal

Immunology and Infection

11.8K Görüntüleme.  RWTH University-Hospital Aachen. Stable intravital high-resolution imaging of immune cells in the liver is challenging. Here we provide a highly sensitive and reliable method to study migration and cell-cell-interactions of immune cells in mouse liver over long periods (about 6 hours) by intravital multiphoton laser scanning microscopy in combination with intensive care monitoring.