The authors acknowledge the Auvergne Regional Council (&#34;Programme Nouveau Chercheur de la R&#233;gion Auvergne&#34; 2013) and the French Agence Nationale de la Recherche and the Direction G&#233;n&#233;rale de L&#39;Offre de Soins (&#34;Programme de Recherche Translationnelle en Sant&#233;&#34; ANR-13-PRTS-0010) for the grants. The funders had no influence in the study design, conduct, and analysis or in the preparation of this article.

1. Culture of Alveolar Epithelial Cells (hAELVi)
<ol>
	<li>Thawing
	<ol>
		<li>Pipette 4 mL of cultivation ready-to-use human alveolar epithelial (huAEC) medium in a 15 mL plastic tube and quickly thaw the vial in a preheated water bath (37 &#176;C).</li>
		<li>Transfer the thawed cell suspension to a 15 mL plastic tube containing 4 mL of the medium before centrifuging the tube at 200 x g for 5 min.</li>
		<li>Aspirate the supernatant and resuspend the cell pellet with 5 mL of the cultivation medium. Then, transfer the...

<ol>
	<li>Bellani, G., Laffey, J. 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=Epidemiology,+Patterns+of+Care,+and+Mortality+for+Patients+With+Acute+Respiratory+Distress+Syndrome+in+Intensive+Care+Units+in+50+Countries.">Epidemiology, Patterns of Care, and Mortality for Patients With Acute Respiratory Distress Syndrome in Intensive Care Units in 50 Countries.</a> JAMA:T Journal of the American Medical Association. 315 (8), 788-800 (2016).</li><li>Thompson, B. T., Chambers, R. C., Liu, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+Respiratory+Distress+Syndrome.">Acute Respiratory Distress Syndrome.</a> The New England Journal of Medicine. 377 (6), 562-572 (2017).</li><li>Weiser, T. G., Regenbogen, S. 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=An+estimation+of+the+global+volume+of+surgery:+a+modelling+strategy+based+on+available+data.">An estimation of the global volume of surgery: a modelling strategy based on available data.</a> The Lancet. (9633), 139-144 (2008).</li><li>Khuri, S. F., Henderson, W. 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=Determinants+of+long-term+survival+after+major+surgery+and+the+adverse+effect+of+postoperative+complications.">Determinants of long-term survival after major surgery and the adverse effect of postoperative complications.</a> Annals of Surgery. 242 (3), 341-343 (2005).</li><li>De Conno, E., Steurer, M. P., 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=Anesthetic-induced+improvement+of+the+inflammatory+response+to+one-lung+ventilation.">Anesthetic-induced improvement of the inflammatory response to one-lung ventilation.</a> Anesthesiology. 110 (6), 1316-1326 (2009).</li><li>Fu, H., Sun, M., Miao, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+different+concentrations+of+isoflurane+pretreatment+on+respiratory+mechanics,+oxygenation+and+hemodynamics+in+LPS-induced+acute+respiratory+distress+syndrome+model+of+juvenile+piglets.">Effects of different concentrations of isoflurane pretreatment on respiratory mechanics, oxygenation and hemodynamics in LPS-induced acute respiratory distress syndrome model of juvenile piglets.</a> Experimental Lung Research. 41 (8), 415-421 (2015).</li><li>Reutershan, J., Chang, D., Hayes, J. K., Ley, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protective+effects+of+isoflurane+pretreatment+in+endotoxin-induced+lung+injury.">Protective effects of isoflurane pretreatment in endotoxin-induced lung injury.</a> Anesthesiology. (3), 511-517 (2006).</li><li>Uhlig, C., Bluth, 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=Effects+of+Volatile+Anesthetics+on+Mortality+and+Postoperative+Pulmonary+and+Other+Complications+in+Patients+Undergoing+Surgery:+A+Systematic+Review+and+Meta-analysis.">Effects of Volatile Anesthetics on Mortality and Postoperative Pulmonary and Other Complications in Patients Undergoing Surgery: A Systematic Review and Meta-analysis.</a> Anesthesiology: The Journal of the American Society of Anesthesiologists. 124 (6), 1230-1245 (2016).</li><li>Li, Q. F., Zhu, Y. S., Jiang, H., Xu, H., Sun, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isoflurane+preconditioning+ameliorates+endotoxin-induced+acute+lung+injury+and+mortality+in+rats.">Isoflurane preconditioning ameliorates endotoxin-induced acute lung injury and mortality in rats.</a> Anesthesia and Analgesia. (5), 1591-1597 (2009).</li><li>Voigtsberger, S., Lachmann, R. 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=Sevoflurane+ameliorates+gas+exchange+and+attenuates+lung+damage+in+experimental+lipopolysaccharide-induced+lung+injury.">Sevoflurane ameliorates gas exchange and attenuates lung damage in experimental lipopolysaccharide-induced lung injury.</a> Anesthesiology. (6), 1238-1248 (2009).</li><li>Englert, J. A., Macias, A. 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=Isoflurane+Ameliorates+Acute+Lung+Injury+by+Preserving+Epithelial+Tight+Junction+Integrity.">Isoflurane Ameliorates Acute Lung Injury by Preserving Epithelial Tight Junction Integrity.</a> Anesthesiology. (2), 377-388 (2015).</li><li>Jabaudon, M., Boucher, P., 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=Sevoflurane+for+Sedation+in+ARDS:+A+Randomized+Controlled+Pilot+Study.">Sevoflurane for Sedation in ARDS: A Randomized Controlled Pilot Study.</a> American Journal of Respiratory and Critical. , (2016).</li><li>Blondonnet, R., Audard, J., 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=RAGE+inhibition+reduces+acute+lung+injury+in+mice.">RAGE inhibition reduces acute lung injury in mice.</a> Scientific Reports. 7 (1), (2017).</li><li>Jabaudon, M., Blondonnet, 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=Soluble+Receptor+for+Advanced+Glycation+End-Products+Predicts+Impaired+Alveolar+Fluid+Clearance+in+Acute+Respiratory+Distress+Syndrome.">Soluble Receptor for Advanced Glycation End-Products Predicts Impaired Alveolar Fluid Clearance in Acute Respiratory Distress Syndrome.</a> American Journal of Respiratory and Critical Care Medicine. 192 (2), 191-199 (2015).</li><li>Jabaudon, M., Blondonnet, 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=Soluble+Forms+and+Ligands+of+the+Receptor+for+Advanced+Glycation+End-Products+in+Patients+with+Acute+Respiratory+Distress+Syndrome:+An+Observational+Prospective+Study.">Soluble Forms and Ligands of the Receptor for Advanced Glycation End-Products in Patients with Acute Respiratory Distress Syndrome: An Observational Prospective Study.</a> PloS One. 10 (8), e0135857 (2015).</li><li>Kuehn, A., Kletting, 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=Human+alveolar+epithelial+cells+expressing+tight+junctions+to+model+the+air-blood+barrier.">Human alveolar epithelial cells expressing tight junctions to model the air-blood barrier.</a> ALTEX. 33 (3), 251-260 (2016).</li><li>Yue, T., Roth Z'graggen, 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=Postconditioning+with+a+volatile+anaesthetic+in+alveolar+epithelial+cells+in+vitro.">Postconditioning with a volatile anaesthetic in alveolar epithelial cells in vitro.</a> The European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology. 31 (1), 118-125 (2008).</li><li>Suter, D., Spahn, D. 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=The+immunomodulatory+effect+of+sevoflurane+in+endotoxin-injured+alveolar+epithelial+cells.">The immunomodulatory effect of sevoflurane in endotoxin-injured alveolar epithelial cells.</a> Anesthesia and Analgesia. (3), 638-645 (2007).</li><li>Schl&#228;pfer, M., Leutert, A. C., Voigtsberger, S., Lachmann, R. A., Booy, C., Beck-Schimmer, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sevoflurane+reduces+severity+of+acute+lung+injury+possibly+by+impairing+formation+of+alveolar+oedema.">Sevoflurane reduces severity of acute lung injury possibly by impairing formation of alveolar oedema.</a> Clinical and Experimental Immunology. (1), 125-134 (2012).</li><li>Nickalls, R. W. D., Mapleson, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-related+iso-MAC+charts+for+isoflurane,+sevoflurane+and+desflurane+in+man.">Age-related iso-MAC charts for isoflurane, sevoflurane and desflurane in man.</a> British Journal of Anaesthesia. 91 (2), 170-174 (2003).</li><li>Bourdeaux, D., Sautou-Miranda, 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=Simple+assay+of+plasma+sevoflurane+and+its+metabolite+hexafluoroisopropanol+by+headspace+GC-MS.">Simple assay of plasma sevoflurane and its metabolite hexafluoroisopropanol by headspace GC-MS.</a> Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 878 (1), 45-50 (2010).</li><li>Eger, E. I., Saidman, L. J., Brandstater, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimum+alveolar+anesthetic+concentration.">Minimum alveolar anesthetic concentration.</a> Anesthesiology. 26 (6), 756-763 (1965).</li><li>Perbet, S., Fernandez-Canal, C., Pereira, B., Cardot, J. M., Bazin, J. E., Constantin, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+Richmond+Agitation+Sedation+Scale+According+To+Alveolar+Concentration+of+Sevoflurane+During+a+Sedation+With+Sevoflurane+in+Icu+Patients.">Evaluation of Richmond Agitation Sedation Scale According To Alveolar Concentration of Sevoflurane During a Sedation With Sevoflurane in Icu Patients.</a> Intensive Care Medicine Experimental. 3 (Suppl 1), (2015).</li><li>Goolaerts, A., Pellan-Randrianarison, N., 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=Conditioned+media+from+mesenchymal+stromal+cells+restore+sodium+transport+and+preserve+epithelial+permeability+in+an+in+vitro+model+of+acute+alveolar+injury.">Conditioned media from mesenchymal stromal cells restore sodium transport and preserve epithelial permeability in an in vitro model of acute alveolar injury.</a> American Journal of Physiology. Lung Cellular and Molecular Physiology. 306 (11), L975-L985 (2014).</li></ol>

Our protocol describes an easy method to expose cells to a precise fraction of a halogenated anesthetic agent, such as sevoflurane or isoflurane. Furthermore, we report here&#8212;for the first time&#8212;a rigorous correlation between both the gas fraction and the concentration of sevoflurane and isoflurane inside the culture medium itself. This fundamental step now allows us to safely use our air-tight chamber to study the effects of these halogenated agents in a cultured monolayer of human alveolar epithelial cells.</...

Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by diffuse alveolar injury, lung edema, and hypoxemic respiratory failure. Although ARDS represents more than 10% of intensive care unit (ICU) admissions and nearly 25% of ICU patients requiring mechanical ventilation, it is still an under-recognized challenge for clinicians, with a hospital mortality rate of 35-45%1. Despite intense research, the identification of an effective ARDS pharmacologic therapy or prevention has failed to date. Two major features contribute to mortality in ARDS: impaired alveolar fluid clearance (AFC) (i.e., the altered resorption of alveolar edema fluid from distal lung airspaces) and severe inflammation2. Since ARDS mortality remains high, current initiatives should also include primary prevention; however, a key challenge is to identify at-risk patients in whom ARDS is likely to develop and who would benefit if ARDS were prevented.
Volatile halogenated anesthetics, such as sevoflurane and isoflurane, are widely used to provide general anesthesia in the operating room. Worldwide, more than 230 million patients undergoing major surgery each year require general anesthesia and mechanical ventilation3, and postoperative pulmonary complications adversely affect clinical outcomes and healthcare utilization4. The use of sevoflurane instead of propofol was associated with improved lung inflammation in patients undergoing thoracic surgery and significant decreases in adverse events, such as ARDS and postoperative pulmonary complications5. Similarly, pretreatment with isoflurane had protective effects on respiratory mechanics, oxygenation, and hemodynamics in experimental animal models of ARDS6,7. Although further studies are warranted to address the impact of inhaled agents on outcomes in noncardiac surgery, a similar decrease in pulmonary complications has been recently observed in a meta-analysis, demonstrating that inhaled anesthetic agents&#8212;as opposed to intravenous anesthesia&#8212;are significantly associated with a reduction in mortality for cardiac surgery8.
Specific prospective data about the use of volatile agents for the sedation of ICU patients to prevent or treat lung damage is lacking. However, several trials now support the efficacy and safety of inhaled sevoflurane for the sedation of ICU patients, and preclinical studies have shown that inhaled sevoflurane and isoflurane7,9 improve gas exchange, reduce alveolar edema, and attenuate inflammation in experimental models of ARDS. Additionally, sevoflurane mitigates type II epithelial cell damage10, whereas isoflurane maintains the integrity of the alveolar-capillary barrier through modulation of tight junction protein11. However, further studies are needed to verify to what extent the experimental evidence of organ protection from inhaled sevoflurane and isoflurane could be translated to humans. A first single-center randomized controlled-trial (RCT) from our group found that early use of inhaled sevoflurane in patients with ARDS was associated with improved oxygenation, reduced levels of some pro-inflammatory markers, and reduced lung epithelial damage, as assessed by the levels of the soluble form of the receptor for advanced glycation end-products (sRAGE) in plasma and alveolar fluid12.
Taken together, the beneficial effects of sevoflurane and isoflurane on lung injury could point to multiple biological pathways or functional processes that are dependent on the RAGE pathway, namely alveolar fluid clearance (AFC), epithelial injury, translocation of nuclear factor (NF)-&#954;B, and macrophage activation. In addition, sevoflurane may influence the expression of the RAGE protein itself. Since previous research by our research team and others supports pivotal roles for RAGE in alveolar inflammation and lung epithelial injury/repair during ARDS, we designed an experimental model to provide a translational understanding of the mechanisms of sevoflurane in lung injury and repair13,14,15. The in vitro effects of sevoflurane and isoflurane were investigated in a novel human alveolar epithelial primary cell line specifically designed to study the air-blood barrier of the peripheral lung, hAELVi (human Alveolar Epithelial LentiVirus immortalized), with alveolar type I-like characteristics including functional tight junctions16.
While preparing the design of our in vitro investigations (e.g., cultures of alveolar epithelial cells at the air-liquid interface with exposure to &#34;inhaled&#34; sevoflurane or isoflurane, we understood from previously published studies that fractions of sevoflurane have only been assessed in the &#34;air&#34; interface17,18,19 using standard monitors (similar to those used in a clinical setting). Halogenated agent concentrations were usually chosen according to the minimum alveolar concentration (MAC) values (e.g., in humans, for sevoflurane, 0.5, 1.1, and 2.2 vol%, representing 0.25, 0.5, and 1 MAC, respectively; for isoflurane, 0.6, 0.8, and 1.3 vol% representing 0.25, 0.5, and 1 MAC, respectively)20. Indeed, sevoflurane and isoflurane concentrations have never been investigated in the culture medium itself, thus limiting the validity of previous experimental models/instruments. Furthermore, most experiments used an anaerobic jar that was sealed after the air mix containing sevoflurane had been flushed inside. As our goal was to study alveolar epithelial cells under &#34;physiologic&#34; conditions, we believed that such an anaerobic state may not be optimal and would not be compatible with long experimental durations. Therefore, we developed our own system to culture cells at the air-liquid interface and expose them to halogenated agents (sevoflurane and isoflurane) with the aim of providing precise controlled &#34;air&#34; fractions and &#34;medium&#34; concentrations for these agents. In our opinion, this experimental step, which has not been reported to date in the literature, is mandatory prior to any further in vitro investigations of sevoflurane and isoflurane.

<table>
	<tbody>
		<tr>
			<td>Sevoflurane</td>
			<td>Baxter</td>
			<td></td>
			<td>Performing experiments using sevoflurane or isoflurane while being pregnant should be strongly discouraged</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Virbac</td>
			<td></td>
			<td>Performing experiments using sevoflurane or isoflurane while being pregnant should be strongly discouraged</td>
		</tr>
		<tr>
			<td>Human Alveolar Epithelial cells</td>
			<td>InScreenex</td>
			<td>INS-CI-1015</td>
			<td></td>
		</tr>
		<tr>
			<td>huAEC Medium (ready-to-use)</td>
			<td>InScreenex</td>
			<td>INS-ME-1013-500ml</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic machine circuit</td>
			<td>Drager</td>
			<td>Fabius</td>
			<td></td>
		</tr>
		<tr>
			<td>Gas analyzer</td>
			<td>Drageer</td>
			<td>Vamos Plus</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic gas filter</td>
			<td>SedanaMedical</td>
			<td>FlurAbsord</td>
			<td></td>
		</tr>
		<tr>
			<td>Heated Humifier</td>
			<td>Fisher&#38;Paykel</td>
			<td>MR850</td>
			<td></td>
		</tr>
		<tr>
			<td>Chamber</td>
			<td>Curver</td>
			<td>00012-416-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Gas chromatography coupled with mass detection</td>
			<td>Thermo Fisher Scientific, San Jose, CA, USA</td>
			<td>Trace 1310 with TSQ 8000evo</td>
			<td></td>
		</tr>
		<tr>
			<td>Fused-silica column (30 m x 1.4 &#181;m, 0.25 mm ID)</td>
			<td>Restek, Lisses, France</td>
			<td>Rxi-624Sil MS</td>
			<td></td>
		</tr>
	</tbody>
</table>

in vitro method to control concentrations of halogenated gases in cultured alveolar epithelial cells

Acute respiratory distress syndrome (ARDS) is a syndrome of diffuse alveolar injury with impaired alveolar fluid clearance and severe inflammation. The use of halogenated agents, such as sevoflurane or isoflurane, for the sedation of intensive care unit (ICU) patients can improve gas exchange, reduce alveolar edema, and attenuate inflammation during ARDS. However, data on the use of inhaled agents for continuous sedation in the ICU to treat or prevent lung damage is lacking. To study the effects of halogenated agents on alveolar epithelial cells under "physiologic" conditions, we describe an easy system to culture cells at the air-liquid interface and expose them to halogenated agents to provide precise controlled "air" fractions and "medium" concentrations for these agents. We developed a sealed air-tight chamber in which plates with human alveolar epithelial immortalized cells could be exposed to a precise, controlled fraction of sevoflurane or isoflurane using a continuous gas flow provided by an anesthetic machine circuit. Cells were exposed to 4% of sevoflurane and 1% of isoflurane for 24 hours. Gas mass spectrometry was performed to determine the concentration of halogenated agents dissolved in the medium. After the first hour, the concentrations of sevoflurane and isoflurane in the medium were 251 mg/L and 25 mg/L, respectively. The curves representing the concentrations of both sevoflurane and isoflurane dissolved in the medium showed similar courses over time, with a plateau reached at one hour after exposure. 
This protocol was specifically designed to reach precise and controlled concentrations of sevoflurane or isoflurane in vitro to improve our understanding of mechanisms involved in epithelial lung injury during ARDS and to test novel therapies for the syndrome.

The concentrations of the sevoflurane and isoflurane, which dissolved in the medium over time, are reported in Table 1 and Table 2, respectively.
The courses of the sevoflurane and isoflurane concentrations in the medium were similar over time. Immediately after the required concentration of halogenated agent was set, concentrations rose over the first hour. A plateau was then reached, which per...

Watch this Scientific Journal Video about In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells at JoVE.com

In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells

We describe an easy protocol specifically designed to reach precise and controlled concentrations of sevoflurane or isoflurane in vitro in order to improve our understanding of mechanisms involved in the epithelial lung injury and to test novel therapies for acute respiratory distress syndrome.

In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells

Acute respiratory distress syndrome (ARDS) is a syndrome of diffuse alveolar injury with impaired alveolar fluid clearance and severe inflammation. The ...

This method can help answer key question in the research field of lung injury and repair such as testing halogenated adjunct as potential novel therapies for acute respiratory distress syndrome. The main advantage of this technique is that it relies on a very simple method to culture the cells and to expose them to halogenated agents in order to reach precise and controlled concentrations. To construct the airtight chamber, use a hermetic polypropylene box with a capacity of 6.5 liters.Drill a 2.5 centimeter diameter hole on the bottom side of the lateral wall of the box. Then insert a corrugated tube with a green mark which will serve as the gas air mixture input pipe. And seal it with silicone.Next, drill a second hole with a 2.5 centimeter diameter on the top side of the opposite lateral wall. Insert another corrugated tube with a red mark and connect it with a charcoal filter which will serve as the gas air mixture output pipe. Then seal it with silicone.Subsequently drill a tight hole with a four millimeter diameter at the center of the wall. Insert the short infusion tubing that is connected at a manifold with a rotating male lure lock. Plug it in to a gas analyzer and seal it with silicone.Then place a digital thermometer inside the airtight chamber. Under a laboratory extractor hood, customize an anesthetic machine circuit to switch the nitrous oxide gas line by carbon dioxide. Insert a heated humidifier into the pipe between the anesthetic machine and the airtight chamber to warm the gas flow mixture to approximately 37 degrees Celsius.Plug the airtight chamber with the green marked corrugated tube into the customized anesthetic machine circuit. Next, place the airtight chamber on a hot plate set to 37 degrees Celsius. Place a six well plate containing human alveolar epithelial cells into the airtight chamber and seal the lid.Regulate the gas flow rate to quickly obtain 5%of CO2. Then open the halogenated agent evaporator and adjust the desired percentage. Once the target values are achieved, reduce the fresh gas flow rate to one liter per minute.The airtight chamber can be maintained with this gas flow rate as long as necessary for the experiment. The courses of the sevoflurane and isoflurane concentrations in the medium were similar over time. Immediately after the required concentration of halogenated agent was set, concentrations rose over the first hour.A plateau was then reached which persisted until the administration of the halogenated agent was stopped. After administration interruption, concentrations decreased within one hour. Shown here are the fractions of halogenated agent over time in the airtight chamber measured by the gas analyzer.This procedure is relatively inexpensive and very easy to adopt even when researchers have never manipulated an airtight chamber before. Following this procedure, other methods like protein and RNA quantification, immunofluorescence, measurement of protein permeability and free transport can be performed in order to answer questions on the specific effects of the halogenated agents during epithelial lung injury and its resolution. After its development, this technique may pave the way for research in the field of acute respiratory distress syndrome to further study the mechanism involved in epithelial lung injury during ARDS and to test novel therapies.

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6.5K vues.  CHU Clermont-Ferrand. Cette méthode peut aider à répondre à la question clé dans le domaine de la recherche sur les lésions pulmonaires et la réparation, comme l’essai de l’adjonction halogène comme thérapies novatrices potentielles pour le syndrome de détresse respiratoire aiguë. Le principal avantage de cette technique est qu’elle repose sur une méthode très simple pour la culture des cellules et les exposer à des agents halogènes afin d’atteindre des concentrations précises et contrôlé...