Gli studi sono stati supportati da NIH HL75503 a KP.

Tutti gli esperimenti condotti su animali erano come approvato dal Comitato Istituzionale cura degli animali e uso della University of Tennessee Health Science Center. 1. Tubing preparati perfusione Rat Lung <ol><li> Preparare un sistema di tubi con tubi Tygon (# 18) per la perfusione di sangue come mostrato in Figura 1. Collegare trasduttori di pressione (P23XL) e posizionare il tubo sul palco microscopio. </li><li> Regolare la temperatura del bagno d&#39;acqua a 37 ° C. </li><li> Collegare l&#39;ingresso del polmone e di uscita temporanea con tubo Tygon. </li></ol><img alt="Figura 1" fo:content-width="5in" src="/files/ftp_upload/51552/51552fig1highres.jpg" width="500" /> Figura 1. Tubo per perfusione di sangue. Lo schema mostra la configurazione tubo utilizzato per far circolare il sangue attraverso la preparazione polmone isolato. Inoltre, sono indicati i componenti associati attraverso il quale l&#39;i tubis instradato. Uno schema di cuore e polmone è incluso per mostrare siti di collegamento tra il tubo e l&#39;arteria polmonare (PA), e atriale (LA) cannula (linee blu tratteggiate) sinistra. 2. Preparazione dei polmoni Rat isolati <ol><li> Anestetizzare ratti (ratti maschi Sprague-Dawley, 250-300 g) con ketamina (80-100 mg / kg) e con xilazina (5-10 mg / kg). Dopo garantendo un piano chirurgico di anestesia, posizionare l&#39;animale in posizione supina. </li><li> Eseguire tracheostomia, inserire una cannula tracheale (PE-90) e fissare con sutura chirurgica. </li><li> Infondere eparina (100-200 U) nel cuore mediante puntura cardiaca (21 G ago a farfalla), attendere 60 secondi e il sangue exsanguinate (~ 12-15 ml di sangue). </li><li> Preparare due cannule (tubi Tygon, 3 mm di diametro, lunghi 4 centimetri; svasati a una estremità) e riempire con soluzione fisiologica. </li><li> Eseguire una toracotomia. Fare un&#39;incisione (3 mm) sul ventricolo destro e far scorrere l&#39;estremità svasata di una cannula nell&#39;incisione verso la polmonarearteria. Fissare cannula dell&#39;arteria polmonare con suture chirurgiche. </li><li> Incidere (3 mm) all&#39;apice del ventricolo sinistro e far scorrere l&#39;estremità svasata della seconda cannula nell&#39;incisione. Guida la cannula in atrio sinistro. Fissare cannula al ventricolo sinistro con un nastro ombelicale (2 mm di larghezza). </li><li> Sezionare qualsiasi tessuto connettivo, e rimuovere il polmone e cuore insieme alle cannule allegate. Posizionare polmone e cuore su un piatto di Petri. Riposizionare il polmone modo che la superficie diaframmatica è in cima. I tre cannule devono affrontare la stessa direzione. </li><li> Posizionare la preparazione polmone in una fase che può essere manipolata nelle direzioni XY. Ogni fase che viene con un microscopio può essere modificato per tenere il tubo o una fase fatta su misura, se necessario. </li></ol> 3. Perfusione sanguigna dei polmoni Rat isolati <ol><li> Mescolare il sangue dissanguato con albumina uguale volume (5%) soluzione e aggiungere al serbatoio. Avviare la pompa peristaltica e impostare il flusso rmangiato a 14 ml / min. Lasciare che il sangue per riempire il tubo. </li><li> Con lo shunt aperto, rimuovere il connettore di ingresso-uscita del polmone temporaneo. Attaccare l&#39;arteria polmonare e sinistra cannula atriale all&#39;ingresso polmone e di uscita, rispettivamente. Assicurarsi che non ci siano bolle d&#39;aria nel tubo. </li><li> Collegare la cannula tracheale di un terzo trasduttore di pressione (P23XL). Gonfiare polmoni con il 30% di ossigeno attraverso la cannula tracheale e mantenere la pressione alle 5 cm H 2 O. </li><li> Chiudere lo shunt con un morsetto per iniziare perfusione polmonare. Mantenere arteria polmonare e di sinistra pressioni atriali a ~ 10 e il 3 cm H 2 O, rispettivamente. </li></ol> 4. Preparazione del polmone per microvascolare Infusione <ol><li> Sollevare la parte posteriore del tubo di estensione per il catetere di sopra del livello del polmone e sicuro. </li><li> Preparare un catetere di infusione con l&#39;inserimento di circa 30 cm di 40 cm di lunghezza tubo PE10 in un tubo PE90 ~ 30 cm di lunghezza. Collegare l&#39;estremità esposta del tubo PE10 di un ago (30 G) atached ad una siringa (1 cc). </li><li> Inserire la combinazione catetere nella parte posteriore sollevata del tubo di estensione. Guida la combinazione catetere attraverso l&#39;atrio sinistro e nei polmoni finché non incontra resistenza. Quindi, spingere il catetere PE10 solo ulteriormente nei polmoni finché non incontra resistenza. Si noti che l&#39;applicazione di una forza eccessiva durante l&#39;inserimento del catetere ferire il polmone. </li><li> Riempire la siringa da 1 cc con soluzione di Ringer e legarsi a una pompa a siringa. Impostare la velocità di infusione a 10 ml / min. </li><li> Al sito di infusione diventerà chiaro rispetto al resto del polmone. </li><li> Inumidire il polmone con soluzione salina e coprire il polmone con involucro di plastica con un foro abbastanza grande per lasciare il sito di infusione scoperto. </li><li> Tampone del grasso rubinetto sul fondo di un O-ring (misura) e posizionare un vetrino di vetro (# 1.5, 22 mm di diametro) sul fondo della O-ring. Posizionare delicatamente l&#39;O-ring con il vetrino sul sito di infusione. Fissare l&#39;O-ring con una Hol provetta normader. La combinazione coprioggetto / O-ring non distorce le strutture alveolari sotto di esso, come recentemente riportato 15. </li><li> Posizionare un obiettivo (20X) di un microscopio a fluorescenza sopra l&#39;O-ring e concentrarsi sulla superficie polmonare. </li></ol> 5. Imaging fluorescente Dextran transito attraverso microvasi <ol><li> Preparare il microscopio per l&#39;imaging FITC fioritura. </li><li> Selezionare una regione per essere ripreso e acquisire immagini alla velocità di 1/minuto utilizzando software di acquisizione immagini. </li><li> Iniziare infusione di FITC-destrano 20 kD (0,5 mg / ml) utilizzando la pompa a siringa. Fluorescenza nei vasi sanguigni aumenterà gradualmente e raggiungere un massimo. Continuare infusione per 60 min. </li><li> Quindi, passare a infusione di Ringer per lavare via la fluorescenza luminale. Mantenere infusione per oltre 10 min. Continua l&#39;acquisizione di immagini a 1/min durante il lavaggio-off. </li></ol> 6. Image Analysis <ol><li> Aprire il file di acquisizione delle immagini. </li><li> Regioni postodi interessi per microvasi all&#39;interno della cornice dell&#39;immagine. </li><li> Riprodurre il file immagine del fotogramma per fotogramma e registrare l&#39;intensità di fluorescenza a ciascuna regione di interesse per tutti i fotogrammi. </li><li> Tracciare la variazione di intensità di fluorescenza per ogni regione di interesse in funzione del tempo. </li><li> Quantificare la massima intensità di fluorescenza e l&#39;intensità di fluorescenza residua dopo 10 min di washoff. </li><li> Calcolare il rapporto di massima intensità di fluorescenza residua in ogni regione di interesse per ottenere l&#39;indice di permeabilità per microvasi quella regione di interesse. </li></ol>

<ol>
	<li>Ware, L. B., Matthay, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+acute+respiratory+distress+syndrome.">The acute respiratory distress syndrome.</a> N Engl J Med. 342, 1334-1349 (2000).</li><li>Matthay, M. 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+acute+respiratory+distress+syndrome.">The acute respiratory distress syndrome.</a> J Clin Invest. 122, 2731-2740 (2012).</li><li>Bhattacharya, J., Matthay, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+and+repair+of+the+alveolar-capillary+barrier+in+acute+lung+injury.">Regulation and repair of the alveolar-capillary barrier in acute lung injury.</a> Annu Rev Physiol. 75, 593-615 (2013).</li><li>Parthasarathi, 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=Connexin+43+mediates+spread+of+Ca2+-dependent+proinflammatory+responses+in+lung+capillaries.">Connexin 43 mediates spread of Ca2+-dependent proinflammatory responses in lung capillaries.</a> J Clin Invest. 116, 2193-2200 (2006).</li><li>Parthasarathi, K., Bhattacharya, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localized+Acid+instillation+by+a+wedged-catheter+method+reveals+a+role+for+vascular+gap+junctions+in+spatial+expansion+of+Acid+injury.">Localized Acid instillation by a wedged-catheter method reveals a role for vascular gap junctions in spatial expansion of Acid injury.</a> Anat Rec (Hoboken). 294, 1585-1591 (2011).</li><li>Gorin, A. B., Stewart, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+permeability+of+endothelial+and+epithelial+barriers+to+albumin+flux.">Differential permeability of endothelial and epithelial barriers to albumin flux.</a> J Appl Physiol Respir Environ Exerc Physiol. 47, 1315-1324 (1979).</li><li>Boutoille, 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=FITC-albumin+as+a+marker+for+assessment+of+endothelial+permeability+in+mice:+comparison+with+125I-albumin.">FITC-albumin as a marker for assessment of endothelial permeability in mice: comparison with 125I-albumin.</a> Exp Lung Res. 35, 263-271 (2009).</li><li>Thorball, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FITC-dextran+tracers+in+microcirculatory+and+permeability+studies+using+combined+fluorescence+stereo+microscopy,+fluorescence+light+microscopy+and+electron+microscopy.">FITC-dextran tracers in microcirculatory and permeability studies using combined fluorescence stereo microscopy, fluorescence light microscopy and electron microscopy.</a> Histochemistry. 71, 209-233 (1981).</li><li>Stevens, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+and+molecular+heterogeneity+of+pulmonary+endothelial+cells.">Functional and molecular heterogeneity of pulmonary endothelial cells.</a> Proc Am Thorac Soc. 8, 453-457 (2011).</li><li>Ofori-Acquah, S. F., 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=Heterogeneity+of+barrier+function+in+the+lung+reflects+diversity+in+endothelial+cell+junctions.">Heterogeneity of barrier function in the lung reflects diversity in endothelial cell junctions.</a> Microvasc Res. 75, 391-402 (2008).</li><li>Kandasamy, 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=Real-time+imaging+reveals+endothelium-mediated+leukocyte+retention+in+LPS-treated+lung+microvessels.">Real-time imaging reveals endothelium-mediated leukocyte retention in LPS-treated lung microvessels.</a> Microvasc Res. 83, 323-331 (2012).</li><li>Kandasamy, 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=Lipopolysaccharide+induces+endoplasmic+store+Ca2+-dependent+inflammatory+responses+in+lung+microvessels.">Lipopolysaccharide induces endoplasmic store Ca2+-dependent inflammatory responses in lung microvessels.</a> PloS One. 8, (2013).</li><li>Qiao, R. L., Bhattacharya, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Segmental+barrier+properties+of+the+pulmonary+microvascular+bed.">Segmental barrier properties of the pulmonary microvascular bed.</a> J Appl Physiol. 71, 2152-2159 (1991).</li><li>Parthasarathi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+connexin43+mediates+acid-induced+increases+in+pulmonary+microvascular+permeability.">Endothelial connexin43 mediates acid-induced increases in pulmonary microvascular permeability.</a> Am J Physiol Lung Cell Mol Physiol. 303, (2012).</li><li>Wu, Y., Perlman, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+methods+for+assessing+alveolar+mechanics.">In situ methods for assessing alveolar mechanics.</a> J Appl Physiol 1985. 112, 519-526 (2012).</li><li>Kuebler, W. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+signaling+mechanism+between+gas+and+blood+compartments+of+the+lung.">A novel signaling mechanism between gas and blood compartments of the lung.</a> Journal Clin Invest. 105, 905-913 (2000).</li></ol>

Gli autori non hanno nulla da rivelare.

La preparazione isolato polmone sangue perfuso accoppiato con immagini in tempo reale fornisce un semplice strumento per la determinazione delle variazioni di permeabilità in microvasi polmonari singoli. Abbiamo applicato questo metodo per definire cambiamenti di permeabilità in risposta alle infusioni di LPS. I nostri dati indicano chiaramente che LPS infusione provocato un aumento della permeabilità microvascolare. Inoltre, i dati indicano anche che i cambiamenti di permeabilità indotte da LPS erano simili in entr...

Aumento della permeabilità microvascolare nei polmoni porta allo sviluppo di edema alveolare e gli scambi gassosi compromessa ed è un importante caratteristica del danno polmonare acuto (ALI) 1-3. Pertanto, le stime di permeabilità vascolare sono importanti nel definire l&#39;entità del danno polmonare e l&#39;efficacia degli interventi terapeutici proposti. Analisi gravimetrica come rapporto polmone gratuito sangue wet-to-dry e coefficiente di filtrazione microvascolare sono ampiamente utilizzati metodi per stimare la permeabilità 4,5. Altri metodi includono quantificare la ritenzione di sonde radioattive o fluorescenti nel tessuto polmonare 6-8. Tuttavia, i metodi di cui sopra richiedono un&#39;elaborazione postexperiment di campioni di tessuto polmonare verso chiarire i dati di permeabilità. Inoltre, poiché un animale può essere utilizzato solo per un protocollo singolo trattamento, possono essere necessari grandi numeri di animali per uno studio completo. Una caratteristica comune dei metodi sopra descritti è che essi determinano la permeabilità vascolare medio pertutti i vasi sanguigni all&#39;interno del campione di tessuto. Tuttavia, è noto che polmonari micro-e macro-vasi sono fenotipicamente diversi 9. Quindi, risposte permeabilità possono essere eterogenei tra i vari segmenti di flotta e 9,10. Così, quantificando la permeabilità media di tutti i vasi polmonari in un campione di tessuto può non riflettere adeguatamente tale eterogeneità. Nella preparazione isolato polmone sangue perfuso, vasi sanguigni sulla superficie polmonare possono essere visualizzati tramite un microscopio verticale 4,11,12. In questo modo le risposte che caratterizzano in singoli vasi e, quindi, affrontare qualsiasi eterogeneità nelle risposte 13. Inoltre, utilizzando imaging di fluorescenza di microvasi, saggi di fluorescenza base possono essere incorporati. Inoltre, un microcatetere atriale sinistro può essere utilizzato per fornire agenti e sonde di fluorescenza nei vasi sanguigni 11,14. Microcatetere limita la consegna di una piccola regione polmonare, così exche propone solo i vasi sanguigni all&#39;interno della regione agli agenti infusi e fluorofori. Questo consente a più piccole regioni dello stesso polmone da utilizzare per esperimenti separati, portando ad una riduzione complessiva animali necessari per uno studio. L&#39;imaging in tempo reale consente l&#39;acquisizione dei cambiamenti dinamici nella vascolare e fluorescenza extravascolare singoli microvasi della preparazione polmone isolato. Così, per ogni microvasi all&#39;interno di un campo immagine, cambiamenti nella fluorescenza durante l&#39;infusione di fluorofori e washoff possono essere registrati, e quantificati in linea 14. Utilizzando i valori di fluorescenza massima e residua vascolare, un indice di permeabilità per ogni microvasi nel campo dell&#39;imaging può essere determinato. Per determinare le variazioni di permeabilità in risposta ad agenti infiammatori o pregiudizievoli, l&#39;agente desiderato può essere somministrato prima e poi l&#39;indice di permeabilità determinato. Inoltre, il campo dell&#39;immagine può essere regolato dovunque nella regione polmonare infusa dallomicrocatetere, consentendo così un elevato grado di flessibilità nella scelta della rete vascolare desiderato. Così, l&#39;isolato di sangue perfuso preparazione del polmone in tandem con le immagini in tempo reale fornisce un modello sperimentale interessante per quantificare permeabilità dei microvasi polmonari singoli.

<table border="0" cellpadding="0" cellspacing="0" width="740">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Tygon Tubing</td>
			<td style="width:108px;">Fisher Scientific</td>
			<td style="width:119px;"></td>
			<td style="width:297px;">#18</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Pressure Transducer</td>
			<td style="width:108px;">Data Sciences International</td>
			<td style="width:119px;">P23XL</td>
			<td>Need quantity 3</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Butterfly Needle</td>
			<td style="width:108px;">Greiner Bio-One</td>
			<td align="right" style="width:119px;">450081</td>
			<td>21G</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Peristaltic pump</td>
			<td style="width:108px;">Cole Parmer</td>
			<td style="width:119px;">Masterflex L/S</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">PE-90 tubing</td>
			<td style="width:108px;">Becton Dickinson</td>
			<td align="right" style="width:119px;">427421</td>
			<td>30 cm needed</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">PE-10 tubing</td>
			<td style="width:108px;">Becton Dickinson</td>
			<td align="right" style="width:119px;">427401</td>
			<td>40 cm needed</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Syringe Pump</td>
			<td style="width:108px;">Braintree Scientific</td>
			<td style="width:119px;">BS8000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">O-ring</td>
			<td style="width:108px;"></td>
			<td style="width:119px;"></td>
			<td>Custom made with a 20 mm diamter hole&#160; and a handle&#160; to secure o-ring to holder</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Upright fluorescence microscope</td>
			<td style="width:108px;">Olympus America</td>
			<td style="width:119px;">BX61WI</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Image Acquisition Software</td>
			<td style="width:108px;">Molecular Devices</td>
			<td style="width:119px;">Metamorph</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">FITC Dextran 20KD</td>
			<td style="width:108px;">Sigma Aldrich</td>
			<td style="width:119px;"></td>
			<td>0.5 mg/ml (A dextran of different molecular size can be selected, if trial experiments indicate its suitability based on the calculated permeability index values)&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Lipopolysaccharide</td>
			<td style="width:108px;">Sigma Aldrich</td>
			<td style="width:119px;"></td>
			<td>Serotype 0111:B4</td>
		</tr>
	</tbody>
</table>

quantifying single microvessel permeability in isolated blood-perfused rat lung preparation

La preparazione isolato polmone sangue perfuso è ampiamente usato per visualizzare e definire segnalazione in singoli microvasi. Accoppiando questa preparazione con la rappresentazione in tempo reale, diventa fattibile per determinare le variazioni di permeabilità delle singole microvasi polmonari. Qui descriviamo passi per isolare i polmoni di ratto e profumato con sangue autologo. Poi, abbiamo delineare misure per infondere fluorofori o agenti attraverso un microcatetere in una piccola regione del polmone. Utilizzando queste procedure descritte, abbiamo determinato un aumento della permeabilità nel ratto microvasi polmonari in risposta alle infusioni di lipopolisaccaride batterico. I dati hanno rivelato che lipopolisaccaride aumentata perdita di liquido in entrambi i segmenti venulare e capillare dei microvasi. Così, questo metodo permette di confrontare le risposte permeabilità tra segmenti vascolari e quindi, definisce alcun eterogeneità nella risposta. Mentre i metodi comunemente usati per definire la permeabilità polmonare richiedono post-elaborazione di campioni di tessuto polmonare, iluso di imaging in tempo reale evita questo requisito come evidente dal presente metodo. Così, la preparazione polmone isolato combinato con l&#39;imaging in tempo reale offre diversi vantaggi rispetto ai metodi tradizionali per determinare la permeabilità microvascolare polmonare, ma è un metodo semplice per sviluppare e implementare.

Un isolato preparazione polmone sangue perfuso collegato al tubo per perfusione e relative apparecchiature è mostrato in Figura 2. A scopo dimostrativo, abbiamo usato un ratto Sprague Dawley, se le procedure qui descritte possono essere utilizzati con qualsiasi specie di ratto. Infusioni attraverso un microcatetere atriale sinistra raggiungono solo una piccola regione del polmone. La regione infuso può essere identificato dal scolorimento infusione indotta (Figura 3). La preparazione ...

Watch this Scientific Journal Video about Quantifying Single Microvessel Permeability in Isolated Blood-perfused Rat Lung Preparation at JoVE.com

Quantifying Single Microvessel Permeability in Isolated Blood-perfused Rat Lung Preparation

La preparazione isolato polmone sangue perfuso rende possibile visualizzare le reti microvasali sulla superficie polmonare. Qui si descrive un metodo per quantificare permeabilità delle singole microvasi nei polmoni isolati utilizzando l&#39;imaging di fluorescenza in tempo reale.

Quantificare singolo microvasi Permeabilità in Isolata Blood-perfusione Rat Lung Preparazione

The isolated blood-perfused lung preparation is widely used to visualize and define signaling in single microvessels. By coupling this preparation with ...

quantifying-single-microvessel-permeability-isolated-blood-perfused

Research

JoVE Journal

Biology

9.4K Views.  The University of Tennessee Health Science Center.  La preparazione isolato polmone sangue perfuso rende possibile visualizzare le reti microvasali sulla superficie polmonare. Qui si descrive un metodo per quantificare permeabilità delle singole microvasi nei polmoni isolati utilizzando l'imaging di fluorescenza in tempo reale. 

Video: Quantifying Single Microvessel Permeability in Isolated Blood-perfused Rat Lung Preparation

Standardized Preparation of Single-Cell Suspensions from Mouse Lung Tissue using the gentleMACS Dissociator

The preparation of single-cell suspensions from tissues is an important prerequisite for many experiments in cellular research. The process of dissociating whole organs requires specific parameters in order to obtain a high number of viable cells in a reproducible manner. The gentleMACS Dissociator optimizes this task with a simple, practical protocol. The instrument contains pre-programmed settings that are optimized for the efficient but gentle dissociation of a variety of tissue types, including mouse lungs. In this publication the use of the gentleMACS Dissociator on lung tissue derived from mice is demonstrated.

Dissociating cells from specific tissue types requires specific parameters for tissue agitation to obtain a high volume of viable, culturable cells. The Miltenyi gentleMACS dissociator optimizes this task with a simple, practical protocol. In this publication the use of this apparatus on lung tissue is explained.

La preparazione standardizzata di Single-Cell Sospensioni da tessuto polmonare del mouse utilizzando il dissociatore gentleMACS

The preparation of single-cell suspensions from tissues is an important prerequisite for many experiments in cellular research. The process of ...

Ricerca

Biologia

Characterization of the Isolated, Ventilated, and Instrumented Mouse Lung Perfused with Pulsatile Flow

The isolated, ventilated and instrumented mouse lung preparation allows steady and pulsatile pulmonary vascular pressure-flow relationships to be measured with independent control over pulmonary arterial flow rate, flow rate waveform, airway pressure and left atrial pressure. Pulmonary vascular resistance is calculated based on multi-point, steady pressure-flow curves; pulmonary vascular impedance is calculated from pulsatile pressure-flow curves obtained at a range of frequencies. As now recognized clinically, impedance is a superior measure of right ventricular afterload than resistance because it includes the effects of vascular compliance, which are not negligible, especially in the pulmonary circulation. Three important metrics of impedance - the zero hertz impedance Z0, the characteristic impedance ZC, and the index of wave reflection RW - provide insight into distal arterial cross-sectional area available for flow, proximal arterial stiffness and the upstream-downstream impedance mismatch, respectively. All results obtained in isolated, ventilated and perfused lungs are independent of sympathetic nervous system tone, volume status and the effects of anesthesia. We have used this technique to quantify the impact of pulmonary emboli and chronic hypoxia on resistance and impedance, and to differentiate between sites of action (i.e., proximal vs. distal) of vasoactive agents and disease using the pressure dependency of ZC. Furthermore, when these techniques are used with the lungs of genetically engineered strains of mice, the effects of molecular-level defects on pulmonary vascular structure and function can be determined.

The following protocol outlines the process of isolating, ventilating and instrumenting mouse lungs to measure steady or pulsatile pulmonary vascular pressure-flow relationships in order to quantify the effects of blood flow, airflow, airway changes and vascular changes on right ventricular afterload.

Caratterizzazione del isolata, ventilata e polmone mouse Instrumented perfusi con flusso pulsatile

The isolated, ventilated and instrumented mouse lung preparation allows steady and pulsatile pulmonary vascular pressure-flow relationships to be measured ...

The ex vivo Isolated Skeletal Microvessel Preparation for Investigation of Vascular Reactivity

The isolated microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of factors that control vessel diameter, and thus, perfusion resistance1-5. This is a classic experimental preparation that was, in large measure, initially described by Uchida et al.15 several decades ago. This initial description provided the basis for the techniques that was extensively modified and enhanced, primarily in the laboratory of Dr. Brian Duling at the University of Virginia6-8, and we present a current approach in the following pages. This preparation will specifically refer to the gracilis arteriole in a rat as the microvessel of choice, but the basic preparation can readily be applied to vessels isolated from nearly any other tissue or organ across species9-13. Mechanical (i.e., dimensional) changes in the isolated microvessels can easily be evaluated in response to a broad array of physiological (e.g., hypoxia, intravascular pressure, or shear) or pharmacological challenges, and can provide insight into mechanistic elements comprising integrated responses in an intact, although ex vivo, tissue. The significance of this method is that it allows for facile manipulation of the influences on the integrated regulation of microvessel diameter, while also allowing for the control of many of the contributions from other sources, including intravascular pressure (myogenic), autonomic innervation, hemodynamic (e.g., shear stress), endothelial dependent or independent stimuli, hormonal, and parenchymal influences, to provide a partial list. Under appropriate experimental conditions and with appropriate goals, this can serve as an advantage over in vivo or in situ tissue/organ preparations, which do not readily allow for the facile control of broader systemic variables. 
The major limitation of this preparation is essentially the consequence of its strengths. By definition, the behavior of these vessels is being studied under conditions where many of the most significant contributors to the regulation of vascular resistance have been removed, including neural, humoral, metabolic, etc. As such, the investigator is cautioned to avoid over-interpretation and extrapolation of the data that are collected utilizing this preparation. The other significant area of concern with regard to this preparation is that it can be very easy to damage cellular components such as the endothelial lining or the vascular smooth muscle, such that variable source of error can be introduced. It is strongly recommended that the individual investigator utilize appropriate measurements to ensure the quality of the preparation, both at the initiation of the experiment and periodically throughout the course of a protocol.

The ex vivo Isolated Skeletal Microvessel Preparation for Investigation of Vascular Reactivity

An ex vivo preparation is described for isolation of the largest gracilis muscle resistance arterioles for interrogation of both vascular responses to vasoactive stimuli and the assessment of basic structural properties via passive wall mechanics.

Il Ex vivo Preparazione isolato microvasi scheletrico per le Indagini di reattività vascolare

The isolated  microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of  factors that control vessel ...

Multi-parameter Measurement of the Permeability Transition Pore Opening in Isolated Mouse Heart Mitochondria

The mitochondrial permeability transition pore (mtPTP) is a non specific channel that forms in the inner mitochondrial membrane to transport solutes with a molecular mass smaller than 1.5 kDa. Although the definitive molecular identity of the pore is still under debate, proteins such as cyclophilin D, VDAC and ANT contribute to mtPTP formation. While the involvement of mtPTP opening in cell death is well established1, accumulating evidence indicates that the mtPTP serves a physiologic role during mitochondrial Ca2+ homeostasis2, bioenergetics and redox signaling 3.
mtPTP opening is triggered by matrix Ca2+ but its activity can be modulated by several other factors such as oxidative stress, adenine nucleotide depletion, high concentrations of Pi, mitochondrial membrane depolarization or uncoupling, and long chain fatty acids4. In vitro, mtPTP opening can be achieved by increasing Ca2+ concentration inside the mitochondrial matrix through exogenous additions of Ca2+ (calcium retention capacity). When Ca2+ levels inside mitochondria reach a certain threshold, the mtPTP opens and facilitates Ca2+ release, dissipation of the proton motive force, membrane potential collapse and an increase in mitochondrial matrix volume (swelling) that ultimately leads to the rupture of the outer mitochondrial membrane and irreversible loss of organelle function.
Here we describe a fluorometric assay that allows for a comprehensive characterization of mtPTP opening in isolated mouse heart mitochondria. The assay involves the simultaneous measurement of 3 mitochondrial parameters that are altered when mtPTP opening occurs: mitochondrial Ca2+ handling (uptake and release, as measured by Ca2+ concentration in the assay medium), mitochondrial membrane potential, and mitochondrial volume. The dyes employed for Ca2+ measurement in the assay medium and mitochondrial membrane potential are Fura FF, a membrane impermeant, ratiometric indicator which undergoes a shift in the excitation wavelength in the presence of Ca2+, and JC-1, a cationic, ratiometric indicator which forms green monomers or red aggregates at low and high membrane potential, respectively. Changes in mitochondrial volume are measured by recording light scattering by the mitochondrial suspension. Since high-quality, functional mitochondria are required for the mtPTP opening assay, we also describe the steps necessary to obtain intact, highly coupled and functional isolated heart mitochondria.

A spectrofluorometric protocol for the measurement of the mitochondrial permeability transition pore opening in isolated mouse heart mitochondria is presented here. The assay involves the simultaneous measurement of mitochondria Ca2+ handling, mitochondrial membrane potential and mitochondrial volume. The procedure for obtaining high-quality and functional heart mitochondria is also described.

Multi-parametro di misura della apertura dei pori di transizione di permeabilità nel Cuore mouse mitocondri isolati

The mitochondrial permeability transition pore (mtPTP) is a non specific channel that forms in the inner mitochondrial membrane to transport solutes with ...

Measuring the Osmotic Water Permeability Coefficient (Pf) of Spherical Cells: Isolated Plant Protoplasts as an Example

Studying AQP regulation mechanisms is crucial for the understanding of water relations at both the cellular and the whole plant levels. Presented here is a simple and very efficient method for the determination of the osmotic water permeability coefficient (Pf) in plant protoplasts, applicable in principle also to other spherical cells such as frog oocytes. The first step of the assay is the isolation of protoplasts from the plant tissue of interest by enzymatic digestion into a chamber with an appropriate isotonic solution. The second step consists of an osmotic challenge assay: protoplasts immobilized on the bottom of the chamber are submitted to a constant perfusion starting with an isotonic solution and followed by a hypotonic solution. The cell swelling is video recorded. In the third step, the images are processed offline to yield volume changes, and the time course of the volume changes is correlated with the time course of the change in osmolarity of the chamber perfusion medium, using a curve fitting procedure written in Matlab (the &#8216;PfFit&#8217;), to yield Pf.

Measuring the Osmotic Water Permeability Coefficient Pf of Spherical Cells: Isolated Plant Protoplasts as an Example

Measuring the osmotic water permeability coefficient (Pf) of cells can help understand the regulatory mechanisms of aquaporins (AQPs). Pf determination in spherical plant cell protoplasts presented here involves protoplasts isolation and numerical analysis of their initial rate of volume change as a result of an osmotic challenge during constant bath perfusion.

Misurare il osmotica dell&#39;acqua Permeabilità Coefficiente (P<sub&gt; F</sub&gt;) Di celle sferiche: protoplasti impianto isolato come un esempio

Studying AQP regulation mechanisms is crucial for the understanding of water relations at both the cellular and the whole plant levels. Presented here is ...

Single-channel Analysis and Calcium Imaging in the Podocytes of the Freshly Isolated Glomeruli

Podocytes (renal glomerular epithelial cells) are known to regulate glomerular permeability and maintain glomerular structure; a key role for these cells in the pathogenesis of various renal diseases has been established since podocyte injury leads to proteinuria and foot process effacement. It was previously reported that various endogenous agents may cause a dramatic overload in intracellular Ca2+ concentration in podocytes, presumably leading to albuminuria, and this likely occurs via calcium-conducting ion channels. Therefore, it appeared important to study calcium handling in the podocytes both under normal conditions and in various pathological states. However, available experimental approaches have remained somewhat limited to cultured and transfected cells. Although they represent a good basic model for such studies, they are essentially extracted from the native environment of the glomerulus. Here we describe the methodology of studying podocytes as a part of the freshly isolated whole glomerulus. This preparation retains the functional potential of the podocytes, which are still attached to the capillaries; therefore, podocytes remain in the environment that conserves the major parts of the glomeruli filtration apparatus. The present manuscript elaborates on two experimental approaches that allow 1) real-time detection of calcium concentration changes with the help of ratiometric confocal fluorescence microscopy, and 2) the recording of the single ion channels activity in the podocytes of the freshly isolated glomeruli. These methodologies utilize the advantages of the native environment of the glomerulus that enable researchers to resolve acute changes in the intracellular calcium handling in response to applications of various agents, measure basal concentration of calcium within the cells (for instance, to evaluate disease progression), and assess and manipulate calcium conductance at the level of single ion channels.

Changes in the intracellular calcium levels in the podocytes are one of the most important means to control the filtration function of glomeruli. Here we explain a high-throughput approach that allows detection of real-time calcium handling and single ion channels activity in the podocytes of the freshly isolated glomeruli.

Monocanale Analisi e Imaging di calcio nei podociti del Freshly Isolato glomeruli

Podocytes (renal glomerular epithelial cells) are known to regulate glomerular permeability and maintain glomerular structure; a key role for these cells ...

Microperfusion Technique to Investigate Regulation of Microvessel Permeability in Rat Mesentery

Experiments to measure the permeability properties of individually perfused microvessels provide a bridge between investigation of molecular and cellular mechanisms regulating vascular permeability in cultured endothelial cell monolayers and the functional exchange properties of whole microvascular beds. A method to cannulate and perfuse venular microvessels of rat mesentery and measure the hydraulic conductivity of the microvessel wall is described. The main equipment needed includes an intravital microscope with a large modified stage that supports micromanipulators to position three different microtools: (1) a beveled glass micropipette to cannulate and perfuse the microvessel; (2) a glass micro-occluder to transiently block perfusion and enable measurement of transvascular water flow movement at a measured hydrostatic pressure, and (3) a blunt glass rod to stabilize the mesenteric tissue at the site of cannulation. The modified Landis micro-occlusion technique uses red cells suspended in the artificial perfusate as markers of transvascular fluid movement, and also enables repeated measurements of these flows as experimental conditions are changed and hydrostatic and colloid osmotic pressure difference across the microvessels are carefully controlled. Measurements of hydraulic conductivity first using a control perfusate, then after re-cannulation of the same microvessel with the test perfusates enable paired comparisons of the microvessel response under these well-controlled conditions. Attempts to extend the method to microvessels in the mesentery of mice with genetic modifications expected to modify vascular permeability were severely limited because of the absence of long straight and unbranched microvessels in the mouse mesentery, but the recent availability of the rats with similar genetic modifications using the CRISPR/Cas9 technology is expected to open new areas of investigation where the methods described herein can be applied.

The modified Landis technique enables paired measurement of the hydraulic conductivity of individual microvessels in the mesentery of normal and genetically modified rats under control and test conditions using microperfusion techniques. It provides a convenient method to evaluate mechanisms that regulate microvessel permeability and transvascular exchange under physiological conditions.

Microperfusione Tecnica per Indagare regolamento di microvasi permeabilità a Rat mesentere

Experiments to measure the permeability properties of individually perfused microvessels provide a bridge between investigation of molecular and cellular ...

Isolation of CD146+ Resident Lung Mesenchymal Stromal Cells from Rat Lungs

Mesenchymal stromal cells (MSCs) are increasingly recognized for their therapeutic potential in a wide range of diseases, including lung diseases. Besides the use of bone marrow and umbilical cord MSCs for exogenous cell therapy, there is also increasing interest in the repair and regenerative potential of resident tissue MSCs. Moreover, they likely have a role in normal organ development, and have been attributed roles in disease, particularly those with a fibrotic nature. The main hurdle for the study of these resident tissue MSCs is the lack of a clear marker for the isolation and identification of these cells. The isolation technique described here applies multiple characteristics of lung resident MSCs (L-MSCs). Upon sacrifice of the rats, lungs are removed and rinsed multiple times to remove blood. Following mechanical dissociation by scalpel, the lungs are digested for 2-3 hr using a mix of collagenase type I, neutral protease and DNase type I. The obtained single cell suspension is subsequently washed and layered over density gradient medium (density 1.073 g/ml). After centrifugation, cells from the interphase are washed and plated in culture-treated flasks. Cells are cultured for 4-7 days in physiological 5% O2, 5% CO2 conditions. To deplete fibroblasts (CD146-) and to ensure a population of only L-MSCs (CD146+), positive selection for CD146+ cells is performed through magnetic bead selection. In summary, this procedure reliably produces a population of primary L-MSCs for further in vitro study and manipulation. Because of the nature of the protocol, it can easily be translated to other experimental animal models.

Isolation of CD146+ Resident Lung Mesenchymal Stromal Cells from Rat Lungs

This protocol describes an isolation technique for obtaining primary lung resident mesenchymal stromal cells from rats, through the use of enzymatic digestion, density gradient separation, plastic adherence and CD146+ magnetic bead selection.

Isolamento di CD146<sup&gt; +</sup&gt; cellule residenti del polmone mesenchimali stromali da Rat Polmoni

Mesenchymal stromal cells (MSCs) are increasingly recognized for their therapeutic potential in a wide range of diseases, including lung diseases. Besides ...

The Mouse Isolated Perfused Kidney Technique

The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. This is a prerequisite for studying the physiology of the isolated organ and for many innovative applications that may be possible in the future, including perfusion decellularization for kidney bioengineering or the administration of anti-rejection or genome-editing drugs in high doses to prime the kidney for transplantation. During the time of the perfusion, the kidney can be manipulated, renal function can be assessed, and various pharmaceuticals administered. After the procedure, the kidney can be transplanted or processed for molecular biology, biochemical analysis, or microscopy.
This paper describes the perfusate and the surgical technique needed for the ex vivo perfusion of mouse kidneys. Details of the perfusion apparatus are given and data are presented showing the viability of the kidney&#39;s preparation: renal blood flow, vascular resistance, and urine data as functional, transmission electron micrographs of different nephron segments as morphological readouts, and western blots of transport proteins of different nephron segments as molecular readout.

The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. The buffers and surgical technique are described in detail.

La tecnica del rene perfusi mouse isolato

The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. This is a ...

An Improved Chemotaxis Assay for the Rapid Identification of Rhizobacterial Chemoattractants in Root Exudates

Chemotaxis identification is very important for the research and application of rhizosphere growth-promoting bacteria. We established a straightforward method to quickly identify the chemoattractants that could induce the chemotactic movement of rhizosphere growth-promoting bacteria on sterile glass slides via simple steps. Bacteria solution (OD600 = 0.5) and sterile chemoattractant aqueous solution were added dropwise on the glass slide at an interval of 1 cm. An inoculating loop was used to connect the chemoattractant aqueous solution to the bacterial solution. The slide was kept at room temperature for 20 min on the clean bench. Finally, the chemoattractant aqueous solution was collected for bacterial counting and microscopic observation. In this study, through multiple comparisons of experimental results, the method overcame multiple shortcomings of traditional bacterial chemotaxis methods. The method reduced the error of plate counting and shortened the experimental cycle. For the identification of chemoattractant substances, this new method can save 2-3 days compared to the traditional method. Additionally, this method allows any researcher to systematically complete a bacterial chemotaxis experiment within 1-2 days. The protocol can be considered a valuable resource for understanding plant-microbe interactions.

Here, we present an improved chemotaxis assay protocol. The goal of this protocol is to reduce the steps and costs of traditional bacterial chemotaxis methods and to serve as a valuable resource for understanding plant-microbe interactions.

Un test di chemiotassi migliorato per la rapida identificazione dei chemioattrattivi rizobatterici negli essudati radicali

Chemotaxis identification is very important for the research and application of rhizosphere growth-promoting bacteria. We established a straightforward ...