This work was supported by EU FP7-ITN Marie-Curie Network program RADDEL. MB and KAJ would like to acknowledge Joe Varguese and Rui Serra Maia for their help and suggestions along the optimization of the Kupffer cell isolation.

All animal experiments were executed in compliance with all relevant guidelines, regulations and regulatory agencies. The protocol being demonstrated was performed under the guidance and approval of the UK Home office regulation
1. Perfusion and Cell Collection (Figure 1)
<img alt="Figure 1" src="/files/ftp_upload/52989/52989fig1.jpg" /> 
Figure 1: Liver Perfusion. After anaesthesia of the mouse, the digestive tract is laterally moved to the left...

<ol>
	<li>Hoffmann, D., 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=Performance+of+novel+kidney+biomarkers+in+preclinical+toxicity+studies.">Performance of novel kidney biomarkers in preclinical toxicity studies.</a> Toxicol Sci. 116 (1), 8-22 (2010).</li><li>Nel, 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=Nanomaterial+Toxicity+Testing+in+the+21st+Century:+Use+of+a+Predictive+Toxicological+Approach+and+High-Throughput+Screening.">Nanomaterial Toxicity Testing in the 21st Century: Use of a Predictive Toxicological Approach and High-Throughput Screening.</a> Accounts of Chemical Research. 46 (3), 607-621 (2013).</li><li>Bregoli, L., 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=Toxicity+of+antimony+trioxide+nanoparticles+on+human+hematopoietic+progenitor+cells+and+comparison+to+cell+lines.">Toxicity of antimony trioxide nanoparticles on human hematopoietic progenitor cells and comparison to cell lines.</a> Toxicology. 262 (2), 121-129 (2009).</li><li>Yamasaki, K., 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=Genomic+Aberrations+and+Cellular+Heterogeneity+in+SV40-Immortalized+Human+Corneal+Epithelial+Cells.">Genomic Aberrations and Cellular Heterogeneity in SV40-Immortalized Human Corneal Epithelial Cells.</a> Investigative Ophthalmology, &amp; Visual Science. 50 (2), 604-613 (2009).</li><li>Motoyoshi, Y., 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=Megalin+contributes+to+the+early+injury+of+proximal+tubule+cells+during+nonselective+proteinuria.">Megalin contributes to the early injury of proximal tubule cells during nonselective proteinuria.</a> Kidney International. 74 (10), 1262-1269 (1038).</li><li>Prozialeck, W. C., Edwards, J. R., Lamar, P. C., Smith, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epithelial+barrier+characteristics+and+expression+of+cell+adhesion+molecules+in+proximal+tubule-derived+cell+lines+commonly+used+for+in+vitro+toxicity+studies.">Epithelial barrier characteristics and expression of cell adhesion molecules in proximal tubule-derived cell lines commonly used for in vitro toxicity studies.</a> Toxicology in Vitro. 20 (6), 942-953 (2006).</li><li>Chamberlain, L. M., Godek, M. L., Gonzalez-Juarrero, M., Grainger, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenotypic+non-equivalence+of+murine+(monocyte-)+macrophage+cells+in+biomaterial+and+inflammatory+models.">Phenotypic non-equivalence of murine (monocyte-) macrophage cells in biomaterial and inflammatory models.</a> J Biomed Mater Res A. 88 (4), 858-871 (2009).</li><li>Kermanizadeh, 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=The+role+of+Kupffer+cells+in+the+hepatic+response+to+silver+nanoparticles.">The role of Kupffer cells in the hepatic response to silver nanoparticles.</a> Nanotoxicology. , (2013).</li><li>Fischer, H. C., Hauck, T. S., Gomez-Aristizabal, A., Chan, W. C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exploring+Primary+Liver+Macrophages+for+Studying+Quantum+Dot+Interactions+with+Biological+Systems.">Exploring Primary Liver Macrophages for Studying Quantum Dot Interactions with Biological Systems.</a> Advanced Materials. 22 (23), 2520-2524 (2010).</li><li>Wan, J. 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=M2+Kupffer+Cells+Promote+M1+Kupffer+Cell+Apoptosis:+A+Protective+Mechanism+Against+Alcoholic+and+Nonalcoholic+Fatty+Liver+Disease.">M2 Kupffer Cells Promote M1 Kupffer Cell Apoptosis: A Protective Mechanism Against Alcoholic and Nonalcoholic Fatty Liver Disease.</a> Hepatology. 59 (1), 130-142 (2014).</li><li>Matsuoka, M., Tsukamoto, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimulation+of+hepatic+lipocyte+collagen+production+by+Kupffer+cell-derived+transforming+growth+factor+&#946;:+Implication+for+a+pathogenetic+role+in+alcoholic+liver+fibrogenesis.">Stimulation of hepatic lipocyte collagen production by Kupffer cell-derived transforming growth factor &#946;: Implication for a pathogenetic role in alcoholic liver fibrogenesis.</a> Hepatology. 11 (4), 599-605 (1990).</li><li>Polakos, N. K., 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=Kupffer+Cell-Dependent+Hepatitis+Occurs+during+Influenza+Infection.">Kupffer Cell-Dependent Hepatitis Occurs during Influenza Infection.</a> The American Journal of Pathology. 168 (4), 1169-1178 (2006).</li><li>Tanner, A., Keyhani, A., Reiner, R., Holdstock, G., Wright, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteolytic+enzymes+released+by+liver+macrophages+may+promote+hepatic+injury+in+a+rat+model+of+hepatic+damage.">Proteolytic enzymes released by liver macrophages may promote hepatic injury in a rat model of hepatic damage.</a> Gastroenterology. 80 (4), 647-654 (1981).</li><li>Knittel, T., 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=Expression+patterns+of+matrix+metalloproteinases+and+their+inhibitors+in+parenchymal+and+non-parenchymal+cells+of+rat+liver:+regulation+by+TNF-&#945;+and+TGF-&#946;1.">Expression patterns of matrix metalloproteinases and their inhibitors in parenchymal and non-parenchymal cells of rat liver: regulation by TNF-&#945; and TGF-&#946;1.</a> Journal of Hepatology. 30 (1), 48-60 (1999).</li><li>Branster, M. V., Morton, R. K. <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+Intact+Liver+Cells.">Isolation of Intact Liver Cells.</a> Nature. 180 (4597), 1283-1284 (1038).</li><li>Smedsr&#248;d, B., Pertoft, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+pure+hepatocytes+and+reticuloendothelial+cells+in+high+yield+from+a+single+rat+liver+by+means+of+Percoll+centrifugation+and+selective+adherence.">Preparation of pure hepatocytes and reticuloendothelial cells in high yield from a single rat liver by means of Percoll centrifugation and selective adherence.</a> Journal of Leukocyte Biology. 38 (2), 213-230 (1985).</li><li>Morin, O., Patry, P., Lafleur, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneity+of+endothelial+cells+of+adult+rat+liver+as+resolved+by+sedimentation+velocity+and+flow+cytometry.">Heterogeneity of endothelial cells of adult rat liver as resolved by sedimentation velocity and flow cytometry.</a> J Cell Physiol. 119 (3), 327-334 (1984).</li><li>Miller, S. B., 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=Purification+of+cells+from+livers+of+carcinogen-treated+rats+by+free-flow+electrophoresis.">Purification of cells from livers of carcinogen-treated rats by free-flow electrophoresis.</a> Cancer Res. 43 (9), 4176-4179 (1983).</li><li>Firme, C. P., Bandaru, 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=Toxicity+issues+in+the+application+of+carbon+nanotubes+to+biological+systems.">Toxicity issues in the application of carbon nanotubes to biological systems.</a> Nanomedicine. 6 (2), 245-256 (2010).</li><li>Ali-Boucetta, H., Al-Jamal, K. T., Kostarelos, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytotoxic+assessment+of+carbon+nanotube+interaction+with+cell+cultures.">Cytotoxic assessment of carbon nanotube interaction with cell cultures.</a> Methods in Molecular Biology. 726, 299-312 (2011).</li><li>Wang, 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=Understanding+and+correcting+for+carbon+nanotube+interferences+with+a+commercial+LDH+cytotoxicity+assay.">Understanding and correcting for carbon nanotube interferences with a commercial LDH cytotoxicity assay.</a> Toxicology. 299 (2-3), 99-111 (2012).</li><li>Wang, J. T. -. W., 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=Magnetically+Decorated+Multiwalled+Carbon+Nanotubes+as+Dual+MRI+and+SPECT+Contrast+Agents.">Magnetically Decorated Multiwalled Carbon Nanotubes as Dual MRI and SPECT Contrast Agents.</a> Advanced Functional Materials. 24 (13), 1880-1894 (2014).</li><li>Li, P. Z., Li, J. Z., Li, M., Gong, J. P., He, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+efficient+method+to+isolate+and+culture+mouse+Kupffer+cells.">An efficient method to isolate and culture mouse Kupffer cells.</a> Immunol Lett. 158 (1-2), 52-56 (2014).</li><li>Froh, M., Konno, A., Thurman, R. G. <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+liver+Kupffer+cells.">Isolation of liver Kupffer cells.</a> Curr Protoc Toxicol. Chapter 14, Unit14 14 (2003).</li></ol>

The following steps are critical to achieve high yield and high viability of Kupffer cells. Aseptic conditions should be used to limit the risk of bacterial and fungal contamination. All instruments need to be sterilized before use. Reagents should be freshly prepared before carrying out the isolation procedure.
The choice of collagenase IV, with low tryptic activity, is crucial. Different lots from the same supplier have different enzymatic activity and they may need to be compared initially ...

The field of nanotoxicology research aims to characterize the biological effect of nanoparticles. Toxicological studies based on in vivo investigations remain the most accurate methods. However, their use is limited by their cost, labor and time requirements1. As alternatives, in vitro assays have been used because of their simplicity and the possibility of developing high-throughput in vitro testing platforms2 - so extending the number of conditions tested. Most nanotoxicological studies are performed using in vitro assays with immortalized cell lines. However, there are concerns regarding the extrapolation of these experimental findings to in vivo toxicological effects3. Indeed, the properties of immortalized cell lines can be significantly different from tissues they were derived from, e.g. genetic transformation4, deterioration of key morphological features5, loss of cellular polarity6 and functional alterations such as the regulation of inflammatory mediators7.
Kupffer cells are the most abundant macrophage population in the body and are directly in contact with blood by lining the wall of liver sinusoids. As part of the reticulo-endothelial system (RES), these macrophages are responsible for the capture of circulating nanoparticles and therefore, constitute a highly suitable model to study nanoparticle toxicity. In vivo8 and in vitro9 studies of inflammatory responses associated with Kupffer cells exposed to nanoparticles have been published elsewhere. Kupffer cells have also been involved in the pathogenesis of liver diseases such as alcoholic liver disease10, liver fibrosis11 or viral hepatitis12. It was reported that isolated Kupffer cells provide useful insight to describe cellular mechanisms involved in liver disruption13,14.
Several methods have been reported to isolate and purify Kupffer cells. Cell isolation can result from mechanical or enzymatic dissociation15. Collagenase digestion shows the advantage of conserving the functional integrity of Kupffer cells, while leading to high Kupffer cell yield16. Many experimental approaches, varying in complexity and costs, have been used to separate Kupffer cells from other liver cell populations. For example, Kupffer cell purity can be achieved by immunoaffinity17, flow electrophoresis18, selective adhesion16 or by centrifugal techniques16, which select cells according to their size and density. A combination of these methods can be chosen to increase the purity of the population16. There is no consensus about the ideal method for Kupffer cell isolation, as it mostly depends on the application and available equipment. However, in the case of nanoparticle toxicity testing, the simplicity and high yield of the technique associated with the functional preservation of Kupffer cells appeared to be most suitable for this application.
The Kupffer cell isolation method reported here is based on a 2-step perfusion method followed by purification on density gradient. The method was modified from the original protocol developed by Smedsr&#248;d et al.16 designed for rat liver cell isolation. Most studies reported and described the isolation of Kupffer cells from rat livers. Herein, we describe a method to isolate Kupffer cells from mouse liver, at a high yield and purity. The use of mice reduces the experiment cost and allows the processing of several livers to obtain large amounts of Kupffer cells for nanoparticle toxicity testing.
In the following protocol, Kupffer cells were incubated with functionalized carbon nanotubes (f-CNTs). The unique physico-chemical properties of CNTs &#8211;i.e. high length to diameter ratio and large surface area, have made CNTs interesting candidates as vectors for therapy and diagnosis purposes. However, concerns have been raised regarding the toxicity of CNTs19, and the development of new in vitro tests aims at increasing the understanding of CNT biological effect. Toxicity in Kupffer cell is associated with a lack of structural integrity of the cell membrane. This is measured by the loss of the cytoplasmic enzyme LDH from the cell into the supernatant. The principle of this method, therefore, is to remove any released LDH and measure what is left in the cells20. This is done in preference to measuring the released LDH in the supernatant because the presence of CNTs in the supernatant interferes with the assay21.
We propose the use of this simple and cost effective Kupffer cell isolation method to isolate high number of functional Kupffer cells. This allows the screening of toxicity of a range of nanoparticles, in a relevant primary macrophage model.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td dir="LTR">Euthatal (pentobarbital sodium)</td>
			<td dir="LTR">Merial</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
		</tr>
		<tr>
			<td dir="LTR">CD1 mice</td>
			<td dir="LTR">Charles River&#160;&#160;</td>
			<td dir="LTR">-</td>
			<td dir="LTR">Mouse weight should vary from 35 to 45 g. We advise the use of male CD1 mice as their weight increase rapidly (e.g. a male CD1 mouse of 7 weeks old exceeds 35 g in weight). It is also advised to contact the animal supplier in advance to arrange for the delivery of older animals. Alternatively animals can be in-house to reach the desired weight.&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">HBSS (Ca2+ and Mg2+ free, with bicarbonate)&#160;&#160;</td>
			<td dir="LTR">Life Technologies&#160;&#160;</td>
			<td dir="LTR">14175-053</td>
			<td dir="LTR">HBSS must be&#160; Ca2+ free.&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Ethylene Glycol Tetraacetic Acid (EGTA) tetrasodium salt&#160;</td>
			<td dir="LTR">Sigma-Aldrich&#160;&#160;</td>
			<td dir="LTR">E8145&#160;&#160;</td>
			<td dir="LTR">EDTA can also be used but EGTA has the advantage of chelating Ca2+ selectively.&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">HEPES (1M)&#160;</td>
			<td dir="LTR">Life Technologies&#160;&#160;</td>
			<td dir="LTR">15630-056&#160;</td>
			<td dir="LTR">100 ml&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Collagenase type IV&#160;</td>
			<td dir="LTR">Worthington&#160;</td>
			<td dir="LTR">CSL-4&#160;</td>
			<td dir="LTR">It is advised to test different batches of collagenase or at least mention to the supplier the product has to be suitable for liver cell isolation&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">&#160;Low glucose DMEM&#160;</td>
			<td dir="LTR">Sigma-Aldrich&#160;&#160;</td>
			<td dir="LTR">D5523&#160;</td>
			<td dir="LTR">500 ml&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">RPMI (with sodium pyruvate and Glutamax&#174;)&#160;</td>
			<td dir="LTR">Life Technologies&#160;&#160;</td>
			<td dir="LTR">12633-012&#160;</td>
			<td dir="LTR">500 ml</td>
		</tr>
		<tr>
			<td dir="LTR">Penicillin/Steptomycin&#160;</td>
			<td dir="LTR">Life Technologies&#160;&#160;</td>
			<td dir="LTR">15140-122</td>
			<td dir="LTR">100 ml</td>
		</tr>
		<tr>
			<td dir="LTR">Fetal Bovine Serum&#160;</td>
			<td dir="LTR">First-Link&#160;&#160;</td>
			<td dir="LTR">60-00-850&#160;</td>
			<td dir="LTR">500 ml&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Trypan blue solution&#160;</td>
			<td dir="LTR">Sigma-Aldrich&#160;</td>
			<td dir="LTR">T8154&#160;</td>
			<td dir="LTR">100 ml&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Coated silica particle solution (Percoll&#174;)</td>
			<td dir="LTR">GE Healtcare&#160;&#160;</td>
			<td dir="LTR">17-0891-02&#160;</td>
			<td dir="LTR">Percoll&#174; is very stable and can be kept for several years&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">1x Phosphate Buffered Saline&#160;&#160;</td>
			<td dir="LTR">Life Technologies&#160;&#160;</td>
			<td dir="LTR">10010-023</td>
			<td dir="LTR">500 ml&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">10x Phosphate Buffered Saline&#160;&#160;</td>
			<td dir="LTR">Life Technologies&#160;&#160;</td>
			<td dir="LTR">70011-036</td>
			<td dir="LTR">500 ml</td>
		</tr>
		<tr>
			<td dir="LTR">Dimethyl sulfoxide&#160;</td>
			<td dir="LTR">Fisher&#160;</td>
			<td dir="LTR">D/4120/PB08&#160;</td>
			<td dir="LTR">500 ml&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">LDH kit (CytoTox 96&#174;)&#160;</td>
			<td dir="LTR">Promega&#160;</td>
			<td dir="LTR">G1781&#160;</td>
			<td dir="LTR">Keep protected from light&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">DMEM phenol red free</td>
			<td dir="LTR">Life Technologies&#160;&#160;</td>
			<td dir="LTR">31053-028&#160;</td>
			<td dir="LTR">500 ml&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">F4/80 antibody (Alexa 488)</td>
			<td dir="LTR">AbD Serotec</td>
			<td dir="LTR">MCA497A488</td>
			<td dir="LTR">Do not dilute, used neat for flow cytometry</td>
		</tr>
		<tr>
			<td dir="LTR">Fluorescent beads</td>
			<td dir="LTR">Sigma</td>
			<td dir="LTR">L2778</td>
			<td dir="LTR">Latex beads, amine-modified polystyrene, fluorescent red. 1 ml</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Name of the Material</td>
			<td>Company&#160;</td>
			<td>Catalog number&#160;</td>
			<td>Comments/Description&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Butterfly blood collection set (23G/305mm long tubing)&#160;&#160;</td>
			<td dir="LTR">BD&#160;</td>
			<td dir="LTR">367288</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Syringe Filters (0.22 &#956;m Blue Rim)&#160;</td>
			<td dir="LTR">Minisart&#160;</td>
			<td dir="LTR">16534-K&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Centrifuge Tubes (50 ml Blue Cap)&#160;</td>
			<td dir="LTR">BD Biosciences, Falcon&#160;</td>
			<td dir="LTR">35 2070&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Petri dish (90 x 15 mm)&#160;</td>
			<td dir="LTR">Thermo Fisher Scientific&#160;&#160;</td>
			<td dir="LTR">BSN 101VR20&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">100 &#956;m cell strainer&#160;&#160;</td>
			<td dir="LTR">BD&#160;&#160;</td>
			<td dir="LTR">352360</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Peristaltic pump&#160;</td>
			<td dir="LTR">Watson Marlow&#160;</td>
			<td dir="LTR">SciQ 300&#160;&#160;</td>
			<td>Rinse tubing before and after each usage with sterile PBS and 70% ethanol.</td>
		</tr>
		<tr>
			<td dir="LTR">24-well plates</td>
			<td dir="LTR">Corning&#160;&#160;</td>
			<td>3526</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">96-well plates&#160;</td>
			<td dir="LTR">Corning&#160;&#160;</td>
			<td dir="LTR">3595</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Centrifuge&#160;</td>
			<td>Eppendorf</td>
			<td>5810R</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Plate reader</td>
			<td>BMG Labtech</td>
			<td>FLUOstar Omega</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Serrefine forceps</td>
			<td>Hammacher GmbH&#160;</td>
			<td>Art. Nr. HSE 004-35 / Cat. Nr. 221-0051</td>
			<td>The serrefine forceps allow to clamp the vessel cannulated with the 23G needle without the need of holding the forceps during the perfusion procedure. URL: (http://www.hammacher.de/Laboratory-Products/Clamps-forceps/Serrefines/HSE-004-35-Serrefine::25126.html)&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Flow cytometry tubes</td>
			<td>BD Biosciences, Falcon&#160;</td>
			<td>352052</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Microcentrifuge tubes (1.5 ml)</td>
			<td>Elkay</td>
			<td>&#160; 000-MICR-150</td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Cell scraper</td>
			<td>BD Biosciences, Falcon</td>
			<td>353086</td>
			<td>Cut blade extremities with a pair of scissors to scrape cells in 24-well plates.</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td dir="LTR">Name of the Reagent</td>
			<td dir="LTR">Company&#160;</td>
			<td dir="LTR">Catalog number&#160;</td>
			<td dir="LTR">Comments/Description&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">&#160;EGTA (Ethylene Glycol Tetraacetic Acid)/HBSS (Hank&#39;s Balanced Salt Solution) Solution&#160;</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR">HBSS containing 0.5 mM EGTA and 25 mM HEPES. Adjust pH to 7.4. Prepare 50 ml for each liver to perfuse.&#160;&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Collagenase Solution&#160;</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR">DMEM low glucose containing collagenase type IV at 100 UI/ml, 15 mM HEPES and 1% Penicllin/Streptamycin (v/v). Adjust pH to 7.4. Prepare 100 ml for each liver to perfuse. After adding the collagenase, it is advised to warm up the solution for 30 min before use. This allows the collagenase activity to be optimum.&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Kupffer Cell Isolation Medium&#160;</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR">RPMI containing, 1% Non-Essential Amino-Acids (v/v),1% glutamax&#174; (v/v) and 1% Penicllin/Streptomycin (v/v). Prepare at least 100 ml for 1-3 livers.&#160;&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Kupffer Cell Culture Medium&#160;</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR">RPMI containing 10% Fetal Bovine Serum, 1% Non-Essential Amino-Acids (v/v),1% Glutamax&#174; (v/v) and 1% Penicllin/Streptamycin (v/v). Prepare at least 100 ml for 1-3 livers.&#160;&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">SIP (solution of isotonic coated silica particles)</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR">Mix 1.7 ml of 10x Phosphate Buffered Saline&#160; with 15.3 ml of Percoll&#174; to obtain 17mL of SIP.</td>
		</tr>
		<tr>
			<td dir="LTR">25% SIP solution&#160;</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR">Mix 5 ml of SIP with 15 ml of 1x Phosphate Buffered Saline&#160;&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">50% SIP solution&#160;</td>
			<td dir="LTR"></td>
			<td></td>
			<td dir="LTR">Mix 10 ml of SIP with 10 ml of 1x Phosphate Buffered Saline&#160;</td>
		</tr>
		<tr>
			<td dir="LTR">Lysis Buffer</td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR">DMEM media with 0.9% Triton X-100</td>
		</tr>
		<tr>
			<td dir="LTR">PBS/BSA Solution</td>
			<td dir="LTR"></td>
			<td></td>
			<td dir="LTR">Prepare fresh Phosphate Buffered Saline pH 7.4 with 1% Bovine Serum Albumin.&#160;</td>
		</tr>
		<tr>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
			<td dir="LTR"></td>
		</tr>
	</tbody>
</table>

kupffer cell isolation for nanoparticle toxicity testing

The large majority of in vitro nanotoxicological studies have used immortalized cell lines for their practicality. However, results from nanoparticle toxicity testing in immortalized cell lines or primary cells have shown discrepancies, highlighting the need to extend the use of primary cells for in vitro assays. This protocol describes the isolation of mouse liver macrophages, named Kupffer cells, and their use to study nanoparticle toxicity. Kupffer cells are the most abundant macrophage population in the body and constitute part of the reticulo-endothelial system (RES), responsible for the capture of circulating nanoparticles. The Kupffer cell isolation method reported here is based on a 2-step perfusion method followed by purification on density gradient. The method, based on collagenase digestion and density centrifugation, is adapted from the original protocol developed by Smedsr&#248;d et al. designed for rat liver cell isolation and provides high yield (up to 14 x 106 cells per mouse) and high purity (&#62;95%) of Kupffer cells. This isolation method does not require sophisticated or expensive equipment and therefore represents an ideal compromise between complexity and cell yield. The use of heavier mice (35-45 g) improves the yield of the isolation method but also facilitates remarkably the procedure of portal vein cannulation. The toxicity of functionalized carbon nanotubes f-CNTs was measured in this model by the modified LDH assay. This method assesses cell viability by measuring the lack of structural integrity of Kupffer cell membrane after incubation with f-CNTs. Toxicity induced by f-CNTs can be measured consistently using this assay, highlighting that isolated Kupffer cells are useful for nanoparticle toxicity testing. The overall understanding of nanotoxicology could benefit from such models, making the nanoparticle selection for clinical translation more efficient.

The number of non-purified parenchymal cells was consistent and ranged between 8 and 14 x 106 cells per mouse (17 isolations were performed). Each mouse isolation was sufficient to plate 16 to 28 wells. Cell viability by trypan blue staining showed cell viability ~95%. Kupffer cells showed a round shape within 30 min of incubation at 37 &#176;C, related to their incomplete adherent morphology (Figure 4A). At 4 hr of incubation and afterwards, cells were spread and cell clusters started to form...

Watch this Scientific Journal Video about Kupffer Cell Isolation for Nanoparticle Toxicity Testing at JoVE.com

Kupffer Cell Isolation for Nanoparticle Toxicity Testing

Liver macrophages, named Kupffer cells, are responsible for the capture of circulating nanoparticles. We describe here a method, of high cell purity and yield, for Kupffer cell isolation. The modified LDH assay is used here to measure the toxicity induced by carbon nanotubes in Kupffer cells.

The large majority of in vitro nanotoxicological studies have used immortalized cell lines for their practicality. However, results from nanoparticle ...

kupffer-cell-isolation-for-nanoparticle-toxicity-testing

Research

JoVE Journal

Immunology and Infection

23.4K 조회수.  King's College London. Liver macrophages, named Kupffer cells, are responsible for the capture of circulating nanoparticles. We describe here a method, of high cell purity and yield, for Kupffer cell isolation. The modified LDH assay is used here to measure the toxicity induced by carbon nanotubes in Kupffer cells. 