This study was supported by the Collaborative Research Centers (CRC) 221 (CRC/TR221-DFG, #324392634; project B03) (to K.H.) and CRC 1181 (CRC-DFG, project B05) (to K.H.), both funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation).

The experimental methods described here have been approved by the government of Mittelfranken, Bavaria, Germany.
1. GvHD induction
<ol>
	<li>Day 0: Total body irradiation of the recipient mice
	<ol>
		<li>Use female CD45.2+ H2kd+ BALB/c mice that are at least 10 weeks old as recipients.</li>
		<li>Weigh and record the weight of the recipient mice prior to GvHD induction. 
		NOTE: Ensure that the recipient has a minimal body weight ...

<ol>
	<li>Ferrara, J. L., Levine, J. E., Reddy, P., Holler, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Graft-versus-host+disease.">Graft-versus-host disease.</a> The Lancet. 373, 1550-1561 (2009).</li><li>Magenau, J., Runaas, L., Reddy, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+understanding+the+pathogenesis+of+graft-versus-host+disease.">Advances in understanding the pathogenesis of graft-versus-host disease.</a> British Journal of Haematology. 173, 190-205 (2016).</li><li>Ball, L. M., Egeler, R. M., Party, E. P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+GvHD:+pathogenesis+and+classification.">Acute GvHD: pathogenesis and classification.</a> Bone Marrow Transplantation. 41, 58-64 (2008).</li><li>Naymagon, 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=Acute+graft-versus-host+disease+of+the+gut:+considerations+for+the+gastroenterologist.">Acute graft-versus-host disease of the gut: considerations for the gastroenterologist.</a> Nature Reviews. Gastroenterology &amp; Hepatology. 14, 711-726 (2017).</li><li>Zeiser, R., Blazar, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preclinical+models+of+acute+and+chronic+graft-versus-host+disease:+how+predictive+are+they+for+a+successful+clinical+translation.">Preclinical models of acute and chronic graft-versus-host disease: how predictive are they for a successful clinical translation.</a> Blood. 127, 3117-3126 (2016).</li><li>Cooke, K. 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=An+experimental+model+of+idiopathic+pneumonia+syndrome+after+bone+marrow+transplantation:+I.+The+roles+of+minor+H+antigens+and+endotoxin.">An experimental model of idiopathic pneumonia syndrome after bone marrow transplantation: I. The roles of minor H antigens and endotoxin.</a> Blood. 88, 3230-3239 (1996).</li><li>Anthony, B. A., Hadley, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+graft-versus-host+disease+and+in+vivo+T+cell+monitoring+using+an+MHC-matched+murine+model.">Induction of graft-versus-host disease and in vivo T cell monitoring using an MHC-matched murine model.</a> Journal of Visualized Experiments. (66), e3697 (2012).</li><li>Beilhack, 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=Prevention+of+acute+graft-versus-host+disease+by+blocking+T-cell+entry+to+secondary+lymphoid+organs.">Prevention of acute graft-versus-host disease by blocking T-cell entry to secondary lymphoid organs.</a> Blood. 111, 2919-2928 (2008).</li><li>Becker, C., Fantini, M. C., Neurath, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+resolution+colonoscopy+in+live+mice.">High resolution colonoscopy in live mice.</a> Nature Protocols. 1, 2900-2904 (2006).</li><li>Buchele, V., 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=Targeting+Inflammatory+T+Helper+Cells+via+Retinoic+Acid-Related+Orphan+Receptor+Gamma+t+Is+Ineffective+to+Prevent+Allo-Response-Driven+Colitis.">Targeting Inflammatory T Helper Cells via Retinoic Acid-Related Orphan Receptor Gamma t Is Ineffective to Prevent Allo-Response-Driven Colitis.</a> Frontiers in Immunology. 9, 1138 (2018).</li><li>Ullrich, E., 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=BATF-dependent+IL-7RhiGM-CSF++T+cells+control+intestinal+graft-versus-host+disease.">BATF-dependent IL-7RhiGM-CSF+ T cells control intestinal graft-versus-host disease.</a> The Journal of Clinical Investigation. 128 (3), 916-930 (2018).</li><li>Kaplan, D. H., 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=Target+antigens+determine+graft-versus-host+disease+phenotype.">Target antigens determine graft-versus-host disease phenotype.</a> Journal of Immunology. 173, 5467-5475 (2004).</li></ol>

The authors have nothing to disclose.

The protocol describes the methodology of induction and mini-endoscopic assessment of the colonic phenotype observed in the course of intestinal GvHD. It serves the wider purpose of enabling scientists to study intestinal GvHD longitudinally and noninvasively over the entire disease course (i.e., from the onset of colonic manifestation and progression until maximal disease activity).
However, there are some critical steps and important limitations inherent to the presented methodologies the ex...

Hematopoietic malignancies directly arising from the hematopoietic stem cell compartment and uncontrolled, rapidly progressing, and severe immune-mediated disorders are often indications to perform allo-HCT1,2. However, although accounting for the occurrence of the prognostic beneficial graft-versus-tumor response, donor lymphocytes are frequently inducing and promoting an unwanted immune-mediated attack of healthy tissue components within the allo-HCT recipient, a process that is called graft-versus-host disease3. Manifestations in the gut, the so-called intestinal GvHD, represent the most dreaded complication of acute GvHD, severe forms of which are routinely associated with a high mortality1,2,4.
Overall, murine models of allo-HCT have emerged as invaluable tools to identify and study immune-mediated mechanisms underlying the pathogenesis of GvHD5. However, kinetic assessment of, for instance, beneficial effects of novel therapeutic interventions over time in live mice is routinely based on the determination of clinical GvHD scores6. While these scores are suitable to reflect, for instance, the overall disease burden (i.e., the systemic GvHD), clinical scores lack the sensitivity to reliably mirror organ-specific manifestations (e.g., in the gut). Hence, conclusions, for instance with respect to gut-protective effects of a given therapeutic intervention, that are based on these scoring systems usually fall short.
Despite major advances through the invention of novel whole-body imaging modalities in combination with the usage of either bioluminescent or fluorescent genetic mouse models7,8, methodologies to directly and specifically assess the intestinal manifestation of GvHD in live mice are lacking. Hence, the rationale behind the protocol of the endoscopic assessment of the intestinal GvHD phenotype described in the next section is to overcome this obstacle. Furthermore, the motivation is also to reduce experimental mice numbers since, so far, a detailed assessment of the cellular, morphological, and molecular characteristics (e.g., by histopathology or molecular biology) of intestinal GvHD manifestation has ultimately required the sacrifice of the experimental mouse.
Our institution has previously reported on the methodology of a mini-endoscopic assessment of colonic manifestations in the course of syngeneic colitis models9. In the protocol presented here, we have refined and adapted the colonoscopic scoring matrix for alloresponse-driven colitis in live mice with intestinal GvHD upon transplantation of alloreactive HCT and donor lymphocytes in an MHC class I fully mismatched setting. We identified four parameters suitable to reflect intestinal GvHD-related colonic lesions. Furthermore, we established a system that allows a fine-tuned grading of any single determinant, resulting in a new score that readily informs the reader about the severity of intestinal GvHD present in a given mouse at a given time point. Histopathological analyses confirmed that an endoscopic score above a certain threshold is reliably predicting moderate-to-high grade tissue inflammation. Hence, mini-endoscopic evaluation appears to represent a working substitute for the gold standard histopathology that routinely requires the sacrifice of the experimental mice. Importantly, this protocol can be applied at virtually any given time point and can be repeatedly used during the course of the disease10,11. Furthermore, in contrast to the usage of bioluminescence-dependent approaches, no labor-intense and time-consuming measures like intercrossing genetically modified mice are required and, hence, the methodology can be applied on virtually any mouse line of interest.
Taken together, given the detrimental clinical perspective of allo-HCT patients with severe intestinal GvHD, rapid scientific progress and more insight into the molecular mechanisms underlying the immune pathogenesis are urgently needed. Similarly, important, ethical considerations demand that the gain of knowledge should be achieved with the usage of the minimal number of experimental mice. Hence, both recognized claims on the research community exploring intestinal GvHD can be advanced by implementing serial mini-endoscopic evaluations of the colon in the experimental work chain to monitor and grade intestinal GvHD in live experimental mouse models, as described and validated in the protocol presented here.

<table border="0" cellpadding="0" cellspacing="0" style="width:1249px;" width="1249">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">BIOBEAM 2000 Gamma Irradiator</td>
			<td style="width:216px;">Gamma-Service Meical GmbH</td>
			<td style="width:152px;"></td>
			<td style="width:479px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Phosphate-buffered saline (PBS )</td>
			<td>Sigma-Aldrich Co. LLC.</td>
			<td>D8662-6x500ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Semken Forceps (lenght: 13 cm; serrated, curved tips)</td>
			<td>Fine Science Tools</td>
			<td>11009-13</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hardened Fine Scissors (lenght: 8,5 cm; straight tips; cutting edge: 24 mm)</td>
			<td>Fine Science Tools</td>
			<td>14090-09</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RPMI-1640 Medium</td>
			<td>Sigma-Aldrich Co. LLC.</td>
			<td>R8758-500ML&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Hypodermic needle (26G)</td>
			<td style="width:216px;">B. Braun Melsungen AG</td>
			<td align="right" style="width:152px;">4657683</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">1 mL syring</td>
			<td style="width:216px;">B. Braun Melsungen AG</td>
			<td style="width:152px;">9166017V</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">50 mL tube</td>
			<td style="width:216px;">Sarstedt Ag &#38; Co.KG</td>
			<td align="right" style="width:152px;">62,547,254</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Cell strainer with a 40 &#181;m mesh screen</td>
			<td style="width:216px;">BD Falcon</td>
			<td>352340</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ammonium chloride (NH4Cl)</td>
			<td>Sigma-Aldrich Co. LLC.</td>
			<td style="width:152px;">11209</td>
			<td>ingredient of ACK lysing buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ethylenediaminetetraacetic acid disodium salt dihydrate (Na2EDTA)</td>
			<td>Carl Roth GmbH &#38; Co.KG</td>
			<td style="width:152px;">8043.2</td>
			<td>ingredient of ACK lysing buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Potassium bicarbonate (KHCO3)</td>
			<td>Merck KGaA</td>
			<td style="width:152px;">1,048,540,500</td>
			<td>ingredient of ACK lysing buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD90.2 MicroBeads, mouse</td>
			<td>Miltenyi Biotec GmbH</td>
			<td>130-049-101</td>
			<td>magnet cell separation to isolate T cell-depleted bone marrow cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Pan T Cell Isolation Kit II, mouse</td>
			<td>Miltenyi Biotec GmbH</td>
			<td>130-095-130</td>
			<td>magnet cell separation to isolate splenic T cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Alexa Fluor 700 anti-mouse CD45.2 Antibody (clone: 104; lot: B252126; RRID: AB_493731)</td>
			<td style="width:216px;">Biolegend</td>
			<td>109822</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Pacific Blue anti-mouse CD3 Antibody (clone: 17A2; lot: B227246; RRID: AB_493645)</td>
			<td style="width:216px;">Biolegend</td>
			<td>100214</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">FITC anti-mouse CD4 Antibody (clone: GK1.5; lot: B225057; RRID: AB_312691)</td>
			<td style="width:216px;">Biolegend</td>
			<td>100406</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PE/Cy7 anti-mouse CD45.1 Antibody (clone: A20; lot: B217246; RRID: AB_1134168)</td>
			<td style="width:216px;">Biolegend</td>
			<td>110730</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">APC/Cy7 anti-mouse CD8a Antibody (clone: 53-6.7, lot: B247008; RRID: AB_312753)</td>
			<td style="width:216px;">Biolegend</td>
			<td>100714</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Filtrated bovine serum&#160;</td>
			<td style="width:216px;">Pan Biotec</td>
			<td>P40-47500</td>
			<td>ingredient of FACS buffer&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">96-well polystyrene V-bottom plates</td>
			<td style="width:216px;">Greiner Bio-One</td>
			<td align="right">651201</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Polystyrene Round-Bottom Tube (5 mL)</td>
			<td style="width:216px;">Falcon</td>
			<td align="right" style="width:152px;">352052</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BD LSRFortessa II flow cytometer</td>
			<td>BD Bioscience Co.</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Insulin syringe with sterile interior (30G)</td>
			<td style="width:216px;">BD</td>
			<td align="right" style="width:152px;">324826</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Oxy Vet Oxymat 3</td>
			<td style="width:216px;">Eickemeyer</td>
			<td style="width:152px;"></td>
			<td>oxygen concentrator&#160; for anesthesia</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">NarkoVet&#160;</td>
			<td style="width:216px;">Eickemeyer</td>
			<td align="right">213062</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Plexiglass chamber&#160;</td>
			<td style="width:216px;">Eickemeyer</td>
			<td align="right">214620</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Straight Forward Telescope</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td>64301 AA</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Protection and Examination Sheath</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td>61029 C</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Examination Sheath with working channel</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td>61029 D</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">Biopsy Forceps</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td style="width:152px;">61071 ZJ&#160;</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;175 Watt SCB XenonLight Source</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td align="right">20132120</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fiber Optic Light Cable</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td style="width:152px;">495 NL</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Image 1 S3 Camera Head</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td align="right">22220030</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Image 1 SCB Camera Control Unit</td>
			<td style="width:216px;">KARL STORZ SE &#38;Co KG</td>
			<td align="right">22200020</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:403px;">LCD monitor</td>
			<td style="width:216px;">Olympus</td>
			<td>OEV181H</td>
			<td>part of the experimental setup for colonoscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Forane / Isofluran</td>
			<td>AbbVie Inc.&#160;</td>
			<td>B506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Formaldehyde solution 37 %</td>
			<td>Carl Roth GmbH &#38; Co.KG</td>
			<td style="width:152px;">7398.1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">5,0 mL Dispenser tip&#160;</td>
			<td style="width:216px;">Eppendorf AG</td>
			<td align="right">30089456</td>
			<td></td>
		</tr>
	</tbody>
</table>

induction of intestinal graft-versus-host disease and its mini-endoscopic assessment in live mice

Acute graft-versus-host disease (GvHD) represents the most severe complication that patients previously undergoing allogeneic hematopoietic stem cell transplantation (allo-HCT) face and is frequently associated with a poor clinical outcome. While, for instance, GvHD manifestations of the skin are usually responsive to established immune-suppressive therapies and are, hence, not taking a fatal course, the presence and the intensity of intestinal GvHD, especially of the mid-to-lower parts of the gut, strongly influence the outcome and overall survival of patients with acute GvHD. Therapeutic options are essentially limited to the classic immune-suppressive agents yielding only moderate disease-mitigating effects. Hence, detailed knowledge about the tissue-resident immune cascade, changes in the intestinal microbiota, and the stromal response prior, upon, and after intestinal GvHD onset are urgently needed to understand the events and mechanisms underlying its pathogenesis and to develop innovative therapeutic options. Murine models of GvHD are frequently employed to identify and functionally assess molecules and pathways putatively driving intestinal GvHD. However, means to specifically monitor and evaluate intestinal inflammation over time are essentially lacking since established scores to assess and grade acute GvHD are routinely comprised of various parameters which rather reflect&#160;systemic GvHD manifestations. The detailed evaluation of intestinal GvHD has been restricted to studies using euthanized mice, thereby essentially excluding longitudinal (i.e., kinetic) analyses of the colonic compartment under a given experimental condition (e.g., antibody-mediated blockade of a proinflammatory cytokine) in live mice (i.e., in vivo). The mini-endoscopic in situ assessment of the distal colon of allo-HCT-treated mice described here allows a) a detailed macroscopic evaluation of different aspects of intestinal inflammation and b) the option to collect tissue samples for downstream analyses at various time points over the course of the observation period. Overall, the mini-endoscopic approach provides a major advance in preclinical noninvasive monitoring and assessment of intestinal GvHD.

The current protocol, describing the mini-endoscopic evaluation of intestinal GvHD-associated lesions of the distal colon, has been established and validated in mice previously subjected to the systemic induction of a severe acute GvHD model. In this study, we used an MHC class I fully mismatched model system in which BALB/c mice were lethally irradiated, followed by the transplantation of T-cell-depleted allogeneic bone marrow and by the administration of GvHD-inducing alloreactive C57BL...

Watch this Scientific Journal Video about Induction of Intestinal Graft-versus-host Disease and Its Mini-endoscopic Assessment in Live Mice at JoVE.com

Induction of Intestinal Graft-versus-host Disease and Its Mini-endoscopic Assessment in Live Mice

Here, we present a protocol that describes allogeneic hematopoietic stem cell transplantation and allows repetitive mini-endoscopic evaluations of the distal colon in situ for the presence, characteristics, and severity of colonic inflammation within live mice suffering from intestinal graft-versus-host disease.

Acute graft-versus-host disease (GvHD) represents the most severe complication that patients previously undergoing allogeneic hematopoietic stem cell ...

Mini-endoscopic evaluation of the colon in live mice provides key experimental support for investigating intestinal manifestations of acute graph-versus-host disease, GvHD, upon allogenic, hematopoietic stem cell transplantation. The non-invasive assessment of acute GvHD-related colitis can function as a working substitute for gold standard histopathology, thereby rendering repeated animal sacrifices to obtain tissue specimens unnecessary. Demonstrating the procedure will be Vera Buchele, a post-doc from my laboratory.One day after total-body irradiation of the recipient BALB/c mice, place a CD-45.1 live 5B6 SJL donor mouse in the prone position on a clean working sheath, and use one 13-cm curved and serrated tip of a simkin forceps to lift the fur at one Achilles heel. Using hardened 8.5-cm fine scissors with straight tips, incise the skin between the forceps and one heel, elongating the incision cranially to facilitate removal of the skin and fur from the hind limbs. When the skin has been removed from the hind limbs, cut through each hip, ankle, and knee joint.Store the thigh and shank of every hind limb in a single 92-mm Petri dish filled with PVS on ice and carefully remove as much muscle as possible from each bone, transferring each cleaned femur and tibia into a 50-mL tube of sterile RPMI 1640 medium on wet ice. To isolate the bone marrow, transfer one bone at a time into a new 92-mL Petri dish filled with fresh RPMI 1640 medium, and use a scalpel to cut the ends off of each bone. Next, use a 1-mL syringe equipped with a 26-gauge needle to flush the bones with 1 mL of fresh medium at a time into a 50-mL collection tube containing 5 mL of medium.When all the bones have been flushed, gently pipette the crumbly bone marrow pieces up and down several times to generate a single-cell suspension before filtering the cells through a 40-micrometer mesh-screen cell strainer into a new 50-mL collection tube. Pellet the cells by centrifugation and re-suspend the cells in 5 mL of ammonium chloride potassium lysis buffer for a three-minute incubation at room temperature. At the end of the incubation, stop the reaction with 10 mL of PVS, and centrifuge the cells again.Re-suspend the pellet in 2 mL of fresh PVS for counting, and set aside a six times 10 to the sixth cell aliquot for downstream flow cytometric analysis. Next, use a commercially available cell purification kit to magnetically deplete the CD90.2-positive T cells from the bone marrow single-cell suspension, according to the manufacturer's instructions, and set aside a one times 10 to the sixth cell aliquot of the T-cell-depleted eluate for downstream flow cytometric analysis of the cell purity and composition before and after separation. Then, use a 1-mL syringe equipped with a 30-gauge needle to inject five times 10 to the fifth T-cell-depleted bone marrow cells in 100 microliters of PVS intravenously into the retrobulbar space of the venous sinus of each irradiated recipient animal.The next day, place a spleen harvested from a donor animal onto a 40-micrometer mesh strainer in a 50-mL collection tube, and use a syringe plunger to press the spleen tissue through the strainer into the tube. Wash the strainer and plunger with PVS to collect all the splenocytes, and pellet the cells by centrifugation. After red blood cell lysis is demonstrated, re-suspend the white blood cells for counting, and set aside a six times 10 to the sixth cell aliquot for downstream flow cytometric analysis.For a total CD3-positive T-cell isolation from total splenocytes, use a commercially available cell purification kit according to the manufacturer's instructions, and set aside a one times 10 to the sixth CD3-positive T-cell aliquot from the positive cell fraction for downstream flow cytometric analysis of the cell purity and composition before and after separation. Then, inject seven times 10 to the fifth alloreactive CD3-positive T cells in 100 microliters of PVS intravenously into the retrobulbar space of each recipient mouse to induce GvHD. To score GvHD-related lesions by mini-endoscopy of the distal colorectal region, lift the tail of a recipient animal just above the tail root with one hand, and use the other hand to carefully insert the endoscope into the rectum via the anus.While the air stream inflates the colorectal lumen, slowly and carefully move the endoscope forward in the aboral direction. To avoid colonic bowel injuries, keep the endoscope in the middle area of the lumen using the live video screen to aid in this positioning. Start recording the video stream and scoring the inflammation, evaluating the GvHD-related inflammation of the colon by scoring the parameters as illustrated.When a scoring spot has been located, move the endoscope gently and slightly back and forth to assess the different parameters. To assess the parameter translucency and stool consistency, position the endoscope at a wider distance in relation to the colonic wall. To assess the granularity and vascularity of the lesion, position the endoscope in the close proximity to the colonic wall, and carefully apply well-dosed tension to the colonic wall with the tip of the endoscope.Upon completion of the scoring process, stop the recording. Compared to controls, allogenic hematopoieic stem cell transplantation as demonstrated produces a reproducibly robust induction of a systemic GvHD phenotype, with progressively increasing clinical GvHD scores in recipient animals. These mini-endoscopically assessable criteria were specifically adapted from previously reported syngeneic colitis in the context of allo-response-driven colitis scoring parameters for the precise description, scoring, and grading of intestinal GvHD-disease-associated lesions in the distal colon.Indeed, the mini-endoscopically based grading system enables an easy discrimination of donor-lymphocyte-receiving mice with severe signs of intestinal inflammation from control mice that are essentially devoid of GvHD. Invalidation of the mini-endoscopically based grading system histopathological studies confirmed that the colon of mice severely affected by GvHD-related inflammation display similarly strong histopathological signs of inflammation. In contrast, colon tissues of control mice displayed no to, at most, mild histopathological signs of inflammation, in agreement with the virtual absence of mini-endoscopically detectable signs of colitis.Furthermore, correlation studies between mini-endoscopically and histopathologically assessed colitis activity and systemic GvHD scores demonstrate that mini-endoscopically determined some scores of less than or equal to three reliably predict the absence of mid-to higher-grade intestinal GvHD-associated colonic inflammation scores obtained from histopathological grading. In addition, the severity of the endoscopically assessed intestinal GvHD shows a correlation with systemic GvHD disease activity. To standardize the results of mini-endoscopic evaluation of colonic inflammation and to ensure comparability across different mice and experiments over time, a defined anatomic site should be selected for scoring.In addition to scoring colonic inflammation, the built-in working channel within the mini-endoscopic setup allows the retrieval of view-guided tissue biopsies applicable to various downstream analyses, such as standard histopathology. Due to the non-invasive nature of the mini-endoscopy, acute GvHD-related colitis can be repeatedly assessed within the same animal at virtually any time, thereby yielding fascinating insights into intestinal GvHD.

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Research

JoVE Journal

Immunology and Infection

9.5K visualizações.  University Hospital Erlangen. A avaliação mini-endoscópica do cólon em camundongos vivos fornece suporte experimental fundamental para investigar manifestações intestinais da doença aguda de gráfico versus hospedeiro, GvHD, sobre transplante alergênico e hematopoiético de células-tronco. A avaliação não invasiva da colite aguda relacionada à GvHD pode funcionar como um substituto de trabalho para histopatologia padrão-ouro, tornando assim repetidos sacrifícios animais para obter amostras de tecido desnece...