Il saggio matrice di collagene è stato sviluppato e migliorato dal lavoro di molti gruppi di ricerca diversi nel corso degli ultimi due o tre decenni. Gli approcci descritti qui per espianti dopaminergici e striatali trarre grandi vantaggi da questi studi. Inoltre, gli autori desiderano ringraziare Asheeta Prasad per il suo aiuto nella creazione di culture espianti striatali. Lavorare in laboratorio è stato finanziato dalla Human Frontier Science Program Organization (Career Development Award), l&#39;Organizzazione olandese di ricerca sulla salute e lo sviluppo (ZonMW-VIDI e ZonMW-TOP), l&#39;Unione Europanian (mdDA-NeuroDev, FP7/2007-2011 , Grant 222.999) (a RJP), e l&#39;Organizzazione olandese per la ricerca scientifica (TopTalent: per ERES).

1. Preparazione di collagene Rat Tail <ol><li> Raccogliere 6-10 code di ratto adulto (è possibile immagazzinare le code a -20 ° C fino al momento dell&#39;uso). </li><li> Bagnare le code in 95% etanolo notte a temperatura ambiente (RT). </li></ol> Dissezione di code di ratto (in cappa di coltura tissutale): (Tenere gli strumenti in etanolo al 70% quando non li utilizzano e assicurarsi che tutte le soluzioni, strumenti e oggetti in vetro utilizzati durante tutta la procedura sono sterili) <ol start="3"><li> Per raccogliere tendini dalle code, tagliare la punta della coda. Tenere estremità grande della coda con una coppia di pinze. Utilizzare un altro paio di pinze per tenere, piegare e rompere la coda vicino alle pinze altri. Scomporre e dei tendini sarà lasciato alle spalle (figura 1A, B). </li><li> Raccogliere i tendini in H 2 O sterile e dopo aver raccolto tutti i tendini spostarli in una nuova petridish sterile H 2 O. </li><li> Prendere 2-3 tendini e distruggeteli con 2 paia di perfunghi porcini in un petridish nuovo sterile H 2 O. Smontare il dispositivo anti-tendinea dei tessuti, come le vene (tessuto tendineo è lucido e riflettente; Figura 1C). Dopo la rimozione di tutti i non-tessuto del tendine, ogni coda produce circa 100-150 mg di tendini. </li><li> Trasferire i tendini a 300 ml di soluzione sterile 3% di acido acetico e mescolare lentamente per tutta la notte a 4 ° C. </li><li> Aggiungi un ulteriore 200 ml di soluzione sterile di acido acetico al 3% e mescolare lentamente per tutta la notte a 4 ° C. </li><li> Centrifugare la soluzione di acido acetico contenente i tendini a ~ 2700 xg per 120 min a 4 ° C a pellet non disciolti tendini e non-tessuto tendineo. </li><li> Durante la centrifugazione preparare tubo di dialisi: <ul><li> tagliare pezzi di 40 cm </li><li> bollire in 500 mM EDTA per 5 min </li><li> cool in sterile H 2 O </li></ul></li><li> Tie un nodo ad una estremità del tubo di dialisi e riempire il tubo con il surnatante della soluzione tendine centrifugato su ghiaccio nella cappa coltura tissutale utilizzando un sistema automatico pipette 25 e una pipetta ml. Evitare la produzione di bolle. Nodo l&#39;altra estremità del tubo e il tubo negozio lamina di alluminio sterile su ghiaccio fino a che tutti i pezzi di tubo vengono riempiti (Figura 1D). </li><li> Preparare 10 l di 0,1 X. MEM sterile, pH 4.0, in cappa coltura tissutale. Aggiungere galleggiante a pezzi di tubo e aggiungerli al pre-raffreddata 0,1 X. soluzione MEM in un becher 10 l. Dializzare notte a 4 ° C mentre lentamente sotto agitazione. Questo dialisi rimuove l&#39;eccesso di acido mantenendo il pH basso. </li><li> Sostituire con una nuova pre-raffreddato 10 l 0,1 X. MEM e mescolare per una notte a 4 ° C. </li><li> Ripetere il passaggio precedente, sostituendo con il nuovo pre-raffreddato 10 l 0,1 X. MEM e mescolare per una notte a 4 ° C. </li><li> Aliquotare soluzione di collagene in sterili provette da 50 ml. Aliquote Conservare a 4 ° C. Tenere 6-12 mesi, gestire solo lo stock di collagene nella cappa coltura tissutale. </li><li> È importante per verificare se il collagene purificato deve essere diluito (in 0.1x MEM) per ottenere risultati ottimali nel matr collageneix saggio. Pertanto, generare una serie di diluizioni di collagene (collagene non diluito, 1:1, 1:2 e 1:5 diluito) ed eseguire saggi matrice di collagene come descritto di seguito per determinare la diluizione ottimale collagene. </li></ol> 2. La dissezione del mesencefalo dopaminergici 7,8 <ol><li> Dissect E14.5 embrioni di topo dall&#39;utero della madre e mantenere in medio L15 su ghiaccio fino al momento dell&#39;uso. </li></ol> Tutte le fasi successive sono eseguite dissezione in L15 mezzo su ghiaccio. <ol start="2"><li> Sezionare il cervello. </li><li> Rimuovere il telencefalo tagliando lungo la parte mediale di ogni vescicola telencefaliche (utilizzare le vescicole telencefaliche per espianti striatali). </li><li> Rimuovere la guaina meningea. </li><li> Fare un taglio dorsoventrale solo rostrale della flessione mesencefalico. </li><li> Fare un altro taglio dorsoventrale appena caudalmente della flessione mesencefalico. </li><li> Fare un taglio lungo la linea mediana rostrocaudal dorsale con un microdissection coltello per esporre il tessuto sottostante mesencefalo ventrale. Fare attenzione a non colpire il tessuto mesencefalo ventrale in quanto contiene i neuroni dopaminergici (Figura 2). </li><li> Fate due tagli rostrocaudal laterale e parallelamente alla linea mediana ventrale per rimuovere il tessuto dorsale mesencefalo. </li><li> Dividere il tessuto rimanente mesencefalo ventrale in espianti con un coltello microdissezione. </li><li> Conservare gli espianti in L15 terreno contenente 5% di FBS su ghiaccio fino al momento dell&#39;uso. </li></ol> 3. La dissezione dello striato Tutte le fasi sono eseguite in dissezione L15 mezzo su ghiaccio. <ol><li> Utilizzare vescicole telencefaliche sezionati durante la dissezione mesencefalo. </li><li> Rimuovere il talamo tagliando tra il talamo e corpo striato con pinze. </li><li> Fare un taglio medio-laterale anteriore del corpo striato per rimuovere le strutture rostrali come il bulbo olfattivo. Ripetere questo passaggio per il tessuto situato caudalmente al corpo striato. </li><li> Posizionela porzione rimanente per ottenere una vista coronale del corpo striato (Figura 2). </li><li> Il corpo striato può essere riconosciuto come una parte un po &#39;meno densa (più trasparente) del tessuto. Sezionare il corpo striato e tagliarla a espianti con un coltello microdissezione. Evitare la chiusura dei tessuti leggermente più scura alla linea mediana, che contiene neuroni che migrano di eminenza laterale e mediale gangliare. </li><li> Conservare gli espianti in L15 terreno contenente 5% di FBS su ghiaccio fino al momento dell&#39;uso. </li></ol> 4. Assemblaggio matrice di collagene saggi Preparazione del collagene (tutti i passaggi su ghiaccio, raffreddato ad utilizzare puntali) <ol><li> Miscelare 860 pl di collagene diluito con 100 pl di MEM 10x e 40 pl di bicarbonato di sodio 1M (NaHCO 3) e mantenere in ghiaccio. Se a questo punto il collagene riscalda che si solidifichi. </li><li> Aggiungere una goccia di 20 pl (circa 5 mm di diametro) di collagene preparato ad una coverslip in un pozzo di un 4-ben piatto Nunce lasciate riposare in un incubatore a CO 2 37 ° C e 5% CO 2 per 30 min (ambiente concentrazione di O 2 è sufficiente). Durante questa incubazione il collagene gelatinizzare. </li></ol> Setup co-coltura in gel di collagene <ol start="3"><li> Dopo che il collagene è gelatinizzato, utilizzare una pipetta con una punta di 200 pl per trasferire un espianto o dopaminergica striatale al collagene. </li><li> Spostare gli espianti in stretta prossimità l&#39;uno all&#39;altro usando un ago. Tenere separati ad una distanza di approssimativamente del diametro di un espianto (circa 200-300 micron) (Figura 2). </li><li> Rimuovere eccesso di terreno e aggiungere 20 ul di collagene preparato sopra degli espianti. Questo spesso causa degli espianti di muoversi. Riposizionare gli espianti utilizzando un ago, come descritto in 4.4. </li><li> Sia il collagene solidificare per 15 min a temperatura ambiente seguita da 30 minuti a 37 ° C e 5% CO 2. </li><li> Dopo che il collagene ha fissato, aggiungere 400 microlitri di emedie xplant e crescere per 2-3 giorni in un incubatore a CO 2 37 ° C e 5% CO 2. </li></ol> 5. Analisi di immunoistochimica e quantificazione Immunoistochimica <ol><li> Per risolvere espianti, delicatamente aggiungere 400 microlitri di 8% paraformaldeide (PFA) in PBS a 400 microlitri di media (e quindi diluendo la PFA al 4%) e lasciar riposare per 1 ora a RT. </li><li> Lavare 3 volte 15 min in PBS a temperatura ambiente. </li><li> Incubare in tampone di bloccaggio (BB; PBS + 1% FBS + 0,1% Triton X-100) per 2 ore. </li><li> Incubare con anticorpo primario in BB a 4 ° C. Per assoni dopaminergici utilizzano anticorpi anti-tirosina idrossilasi (1:1000) 7, per assoni striatali anticorpi anti-DARPP32 (1:500) 9 e per la visualizzazione di tutti i assoni βIII anti-tubulina (1:3000) 7. </li><li> Lavare 5x 1 ora in PBS a temperatura ambiente. </li><li> Incubare con anticorpo secondario coniugato al fluoroforo appropriata (1:500) in BB notte a 4° C. Da questo passaggio per minimizzare l&#39;esposizione degli espianti alla luce (ad esempio, coprire con un foglio di alluminio). </li><li> Lavare tutta la notte in PBS a 4 ° C, seguita da numerosi lavaggi durante il giorno successivo. </li><li> Montare espianti su un vetrino portaoggetti con Prolungare reagente Antifade mezzo di montaggio. Aggiungere una goccia di ~ 10 microlitri su un vetrino per microscopio. Prendere il vetrino e delicatamente immissione sul goccia di soluzione di montaggio con il lato rivolto verso il basso espianto. Evitare di inglobare l&#39;aria sotto de coprioggetto da molto delicatamente abbassare la goccia di soluzione di montaggio. </li></ol> Quantificazione calcolando P / D rapporto <ol start="9"><li> Acquisire immagini digitali degli espianti usando un microscopio a epifluorescenza (Figura 3). </li><li> Utilizzando queste immagini, dividere ogni espianti in quadranti per generare un quadrante prossimale (cioè parte del espianto più vicino al espianto adiacente) e un quadrante distale (parte del espianto più lontana dalla spiegazione adiacentent) (Figura 2, 4). </li><li> Misurare la lunghezza di 20 più lunghe neuriti emergenti dalla espianto sia nei quadranti prossimale e distale. </li><li> Utilizzare la lunghezza media delle 20 più lunghe neuriti per calcolare il rapporto P / D per ogni singolo espianto. AP / D rapporto&gt; 1 indica attrazione assone, mentre un rapporto &lt;1 indica la repulsione degli assoni. </li><li> In alcuni casi, la crescita di neuriti densa impedisce la valutazione della lunghezza neurite individuale. In queste situazioni, la quantificazione può essere effettuata misurando la distanza tra il bordo del espianto e il fronte principale della crescita assonale nei quadranti prossimale e distale. </li></ol> 6. Immagini di rappresentanza Dopo cultura di successo di espianti dopaminergici e striatali un gran numero di assoni sono visibili mediante microscopia luminosa campo o come visualizzato da anti-βIII immunoistochimica tubulina (non mostrato). Un sottoinsieme di questi assoni sarà dopaminergica o s<html> assoni triatal come visualizzato immunocitochimica utilizzando (Figura 3). Dividendo gli espianti in quadranti come descritto e determinare P / D rapporti, un effetto assone putativo attrattiva o repulsiva può essere quantificato (Figura 3E). <img alt="Figura 1" src="/files/ftp_upload/3691/3691fig1.jpg" /> Figura 1. Foto che illustrano la preparazione di collagene da tendini coda di ratto. A) Tirando a parte la coda di topo espone i tendini. B) I tendini sono visibili come corda come bundle. C) I tendini sono facili da distinguere dalle vene per il loro aspetto bianco lucido. D) Dopo dissoluzione dei tendini in acido acetico, la soluzione viene trasferita al tubo di dialisi. Per mantenere il freddo disciolto collagene, provette sono poste su un foglio di alluminio sterile su ghiaccio. e 2 &quot;src =&quot; / files/ftp_upload/3691/3691fig2.jpg &quot;/&gt; Figura 2. Schematica indicante le varie fasi della procedura. Regioni cerebrali appropriate vengono sezionati e tagliati a generare espianti. Un singolo mesencefalo e espianto striatale sono posizionati in stretta prossimità in una matrice di collagene e lasciati crescere per 48-72 ore a 37 ° C. Gli assoni sono visualizzati mediante immunoistochimica a fluorescenza e un rapporto P / D è calcolato per quantificare le risposte chemotropic. <img alt="Figura 3" src="/files/ftp_upload/3691/3691fig3.jpg" /> Figura 3. I risultati rappresentativi mostrano la crescita degli assoni in una cultura matrice di collagene. A) espianto mesencefalo colorate con anticorpo anti-tirosina idrossilasi rivelando l&#39;estensione assonale. Linea tratteggiata indica espianto adiacente. B) ingrandimento di un neuriti che mostrano individuali e coni di crescita (frecce). C) espianto striatale colorate con anticorpi anti-DARPP32. D) Ingrandimento del C mostrando neuriti individuali. E) Esempio diRapporto P / D quantificazione. Espianti sono suddivisi in quadranti uguali. Il quadrante prossimale si trova di fronte l&#39;espianto adiacente, mentre il quadrante distale si trova ad affrontare a partire da esso. Barre di scala indicano 100 micron.

<ol>
	<li>van den Heuvel, D. M., Pasterkamp, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Getting+connected+in+the+dopamine+system.">Getting connected in the dopamine system.</a> Prog. Neurobiol. 85, 75-93 (2008).</li><li>Lobo, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+profiling+of+striatonigral+and+striatopallidal+medium+spiny+neurons+past,+present,+and+future.">Molecular profiling of striatonigral and striatopallidal medium spiny neurons past, present, and future.</a> Int. Rev. Neurobiol. 89, 1-35 (2009).</li><li>Dickson, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+mechanisms+of+axon+guidance.">Molecular mechanisms of axon guidance.</a> Science. 298, 1959-1964 (2002).</li><li>Chilton, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecules+mechanisms+of+axon+guidance.">Molecules mechanisms of axon guidance.</a> Dev. Biol. 292, 13-24 (2006).</li><li>Lumsden, A. G., Davies, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotropic+effect+of+specific+target+epithelium+in+the+developing+mammalian+nervous+system.">Chemotropic effect of specific target epithelium in the developing mammalian nervous system.</a> Nature. 323, 538-539 (1986).</li><li>Tessier-Lavigne, M., Placzek, M., Lumsden, A. G., Dodd, J., Jessel, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotropic+guidance+of+developing+axons+in+the+mammalian+central+nervous+system.">Chemotropic guidance of developing axons in the mammalian central nervous system.</a> Nature. 336, 775-778 (1988).</li><li>Kolk, S. M., Gunput, R. A., Tran, T. S., van den Heuvel, D. M., Prasad, A. A., Hellemons, A. J., Adolfs, Y., Ginty, D. D., Kolodkin, A. L., Burbach, J. P., Smidt, M. P., Pasterkamp, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semaphorin+3F+is+a+bifunctional+guidance+cue+for+dopaminergic+axons+and+controls+their+fasciculation,+channeling,+rostral+growth,+and+intracortical+targeting.">Semaphorin 3F is a bifunctional guidance cue for dopaminergic axons and controls their fasciculation, channeling, rostral growth, and intracortical targeting.</a> J. Neurosci. 29, 12542-12557 (2009).</li><li>Fenstermaker, A. G., Prasad, A. A., Bechara, A., Adolfs, Y., Tissir, F., Goffinet, A., Zou, Y., Pasterkamp, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wnt/planar+cell+polarity+signaling+controls+the+anterior-posterior+organization+of+monoaminergic+axons+in+the+brainstem.">Wnt/planar cell polarity signaling controls the anterior-posterior organization of monoaminergic axons in the brainstem.</a> J. Neurosci. 30, 16053-16064 (2010).</li><li>Arlotta, P., Molyneaux, B. J., Jabaudon, D., Yoshida, Y., Macklis, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ctip2+controls+the+differentiation+of+medium+spiny+neurons+and+the+establishment+of+the+cellular+architecture+of+the+striatum.">Ctip2 controls the differentiation of medium spiny neurons and the establishment of the cellular architecture of the striatum.</a> J. Neurosci. 28, 622-632 (2008).</li><li>De Wit, J., Toonen, R. F., Verhage, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Matrix-dependent+local+retention+of+secretory+vesicle+cargo+in+cortical+neurons.">Matrix-dependent local retention of secretory vesicle cargo in cortical neurons.</a> J. Neurosci. 29, 23-37 (2009).</li><li>G&#228;hwiler, B. H., Capogna, M., Debanne, D., McKinney, R. A., Thompson, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organotypic+slice+cultures:+a+technique+has+come+of+age.">Organotypic slice cultures: a technique has come of age.</a> Trends Neurosci. 20, 471-477 (1997).</li></ol>

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Il saggio matrice di collagene qui descritto è stato utilizzato e migliorato da molti laboratori diversi negli ultimi decenni a indagare su una varietà di molecole e sistemi di orientamento degli assoni neuronali (ad esempio si vedano i riferimenti 5-8). Questi studi hanno dimostrato che questo dosaggio è un potente strumento per studiare gli effetti e la regolazione delle molecole di orientamento degli assoni secrete da diversi (intermedio), tessuti bersaglio. Tuttavia, occorre notare ch...

<table border="1"><tbody><tr><td> Nome del reattivo </td><td> Azienda </td><td> Numero di catalogo </td><td> Comments </td></tr><tr><td> Di siero di vitello fetale </td><td> BioWhittaker </td><td> 14-801F </td><td></td></tr><tr><td> Glutammina (200mm) </td><td> PAA </td><td> M11-004 </td><td></td></tr><tr><td> Hepes </td><td> VWR International </td><td> 441476L </td><td></td></tr><tr><td> β-mercaptoetanolo </td><td> Merck </td><td> 444203 </td><td></td></tr><tr><td> Minimi Essential Media (MEM) </td><td> Gibco </td><td> 61100-087 </td><td></td></tr><tr><td> Neurobasal </td><td> Gibco </td><td> 21103-049 </td><td></td></tr><tr><td> B27 </td><td> Gibco </td><td> 17504-044 </td><td></td></tr><tr><td> Leibovitz L-15 </td><td> Gibco </td><td&gt; 11415-049 </td><td></td></tr><tr><td> Penicillina-Streptomicina </td><td> Gibco </td><td> 15070-063 </td><td></td></tr><tr><td> Prolungare Reagente oro Antifade </td><td> Invitrogen </td><td> P36930 </td><td></td></tr><tr><td> Dialisi tubi </td><td> Spectrum Labs </td><td> 132660 </td><td></td></tr><tr><td> Coniglio anti-tirosina idrossilasi </td><td> Pel-Freez </td><td> P40101-0 </td><td></td></tr><tr><td> Coniglio anti-Darpp32 (H-62) </td><td> Santa-Cruz </td><td> Sc-11365 </td><td></td></tr><tr><td> Topo anti-tubulina βIII </td><td> Sigma </td><td> T8660 </td><td></td></tr><tr><td> Alexa Fluor etichettato anticorpi secondari </td><td> Invitrogen </td><td></td><td></td></tr></tbody></table>

dissection and culture of mouse dopaminergic and striatal explants in three-dimensional collagen matrix assays

Mesencefalo dopamina (mdDA) progetto di neuroni attraverso il fascio proencefalo mediale verso diverse aree del telencefalo, compreso il corpo striato 1. Reciprocamente, i neuroni spinosi medi del corpo striato che danno luogo alla striatonigral (diretto) via innervano la substantia nigra 2. Lo sviluppo di questi tratti assoni dipende dalle azioni combinatorie di una pletora di crescita degli assoni e spunti di orientamento tra le molecole che vengono rilasciati dai neuriti (o intermedio) regioni obiettivo 3,4. Questi fattori solubili possono essere studiate in vitro da mdDA coltura e / o espianti striatali in una matrice di collagene che fornisce un substrato tridimensionale per gli assoni che mimano l&#39;ambiente extracellulare. Inoltre, la matrice di collagene consente la formazione di gradienti relativamente stabili di proteine ​​rilasciate da espianti altri o cellule poste in prossimità (ad esempio si vedano i riferimenti 5 e 6). Qui si descrivono i metodi per i PURificazione di collagene coda di ratto, microdissezione di espianti dopaminergici e striatali, la loro cultura in gel di collagene e la successiva analisi immunoistochimica e quantitativa. In primo luogo, E14.5 il cervello di embrioni di topo sono isolate e dopaminergici e striatali espianti sono microdissezionate. Questi espianti sono poi (co) coltivati ​​in gel di collagene su vetrini coprioggetto per 48 a 72 ore in vitro. Successivamente, le proiezioni assonali sono visualizzati utilizzando marcatori neuronali (ad esempio la tirosina idrossilasi, DARPP32 o tubulina βIII) e la crescita degli assoni e le risposte degli assoni attrattiva o repulsiva vengono quantificati. Questa preparazione neuronale è uno strumento utile per studi in vitro dei meccanismi cellulari e molecolari della crescita degli assoni e mesostriatal striatonigral e guida durante lo sviluppo. Usando questo saggio, è anche possibile valutare altri (intermedio) obiettivi per assoni dopaminergici e striatali o per testare specifici segnali molecolari.

Watch this Scientific Journal Video about Dissection and Culture of Mouse Dopaminergic and Striatal Explants in Three-Dimensional Collagen Matrix Assays at JoVE.com

Dissection and Culture of Mouse Dopaminergic and Striatal Explants in Three-Dimensional Collagen Matrix Assays

Espianti dal sistema dopaminergico mesencefalo e striato sono utilizzati in un saggio per la matrice di collagene<em&gt; In vitro</em&gt; L&#39;analisi dei pathway di sviluppo mesostriatal e striatonigral. In questo saggio crescita degli assoni e la guida può essere manipolato e quantificati. Può anche essere modificato per valutare altre regioni o segnali molecolari.

Dissezione e Cultura del mouse dopaminergici e striatali Espianti di saggi di collagene matrice tridimensionale

Midbrain dopamine (mdDA) neurons project via the medial forebrain bundle towards several areas in the telencephalon, including the striatum1. ...

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25.6K Views.  University Medical Center Utrecht. Espianti dal sistema dopaminergico mesencefalo e striato sono utilizzati in un saggio per la matrice di collagene In vitro L'analisi dei pathway di sviluppo mesostriatal e striatonigral. In questo saggio crescita degli assoni e la guida può essere manipolato e quantificati. Può anche essere modificato per valutare altre regioni o segnali molecolari.

Video: Dissection and Culture of Mouse Dopaminergic and Striatal Explants in Three-Dimensional Collagen Matrix Assays

Dissection and Culture of Commissural Neurons from Embryonic Spinal Cord

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies of these neurons are located in the dorsal spinal cord and their axons follow stereotyped trajectories during embryonic development. Commissural axons initially project ventrally towards the floorplate. After crossing the midline, these axons turn anteriorly and project towards the brain. Each of these steps is regulated by the action of several guidance cues. Cultures highly enriched in commissural neurons are ideally suited for many experiments addressing the mechanisms of axon pathfinding, including turning assays, immunochemistry and biochemistry. Here, we describe a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. First, the spinal cord is isolated and dorsal strips are dissected out. The dorsal tissue is then dissociated into a cell suspension by trypsinization and mechanical disruption. Neurons are plated onto poly-L-lysine-coated glass coverslips or tissue-culture dishes. After 30 hours in vitro, most neurons have extended an axon. The purity of the culture (Yam et al. 2009), typically over 90%, can be assessed by immunolabeling with the commissural neuron markers DCC, LH2 and TAG1 (Helms and Johnson, 1998). This neuronal preparation is a useful tool for in vitro studies of the cellular and molecular mechanisms of commissural axon growth and guidance during spinal cord development.

This video demonstrates a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. Dissociated commissural neurons are useful to study the cellular and molecular mechanisms of axon growth and guidance.

Dissezione e la cultura di neuroni embrionali commissurali da midollo spinale

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies ...

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Neuroscienze

Dissection and Culture of Chick Statoacoustic Ganglion and Spinal Cord Explants in Collagen Gels for Neurite Outgrowth Assays

The sensory organs of the chicken inner ear are innervated by the peripheral processes of statoacoustic ganglion (SAG) neurons. Sensory organ innervation depends on a combination of axon guidance cues1 and survival factors2 located along the trajectory of growing axons and/or within their sensory organ targets. For example, functional interference with a classic axon guidance signaling pathway, semaphorin-neuropilin, generated misrouting of otic axons3. Also, several growth factors expressed in the sensory targets of the inner ear, including Neurotrophin-3 (NT-3) and Brain Derived Neurotrophic Factor (BDNF), have been manipulated in transgenic animals, again leading to misrouting of SAG axons4. These same molecules promote both survival and neurite outgrowth of chick SAG neurons in vitro5,6.
Here, we describe and demonstrate the in vitro method we are currently using to test the responsiveness of chick SAG neurites to soluble proteins, including known morphogens such as the Wnts, as well as growth factors that are important for promoting SAG neurite outgrowth and neuron survival. Using this model system, we hope to draw conclusions about the effects that secreted ligands can exert on SAG neuron survival and neurite outgrowth. 
SAG explants are dissected on embryonic day 4 (E4) and cultured in three-dimensional collagen gels under serum-free conditions for 24 hours. First, neurite responsiveness is tested by culturing explants with protein-supplemented medium. Then, to ask whether point sources of secreted ligands can have directional effects on neurite outgrowth, explants are co-cultured with protein-coated beads and assayed for the ability of the bead to locally promote or inhibit outgrowth. We also include a demonstration of the dissection (modified protocol7) and culture of E6 spinal cord explants. We routinely use spinal cord explants to confirm bioactivity of the proteins and protein-soaked beads, and to verify species cross-reactivity with chick tissue, under the same culture conditions as SAG explants. These in vitro assays are convenient for quickly screening for molecules that exert trophic (survival) or tropic (directional) effects on SAG neurons, especially before performing studies in vivo. Moreover, this method permits the testing of individual molecules under serum-free conditions, with high neuron survival8.

We demonstrate how to dissect and culture chick E4 statoacoustic ganglion and E6 spinal cord explants. Explants are cultured under serum-free conditions in 3D collagen gels for 24 hours. Neurite responsiveness is tested with growth factor-supplemented medium and with protein-coated beads.

Dissezione e Cultura della gangliari Chick Statoacoustic Espianti e del midollo spinale in gel di collagene per saggi crescita dei neuriti

The sensory organs of the chicken inner ear are innervated by the peripheral processes of statoacoustic ganglion (SAG) neurons. Sensory organ innervation ...

A Functional Motor Unit in the Culture Dish: Co-culture of Spinal Cord Explants and Muscle Cells

Human primary muscle cells cultured aneurally in monolayer rarely contract spontaneously because, in the absence of a nerve component, cell differentiation is limited and motor neuron stimulation is missing1. These limitations hamper the in vitro study of many neuromuscular diseases in cultured muscle cells. Importantly, the experimental constraints of monolayered, cultured muscle cells can be overcome by functional innervation of myofibers with spinal cord explants in co-cultures.
Here, we show the different steps required to achieve an efficient, proper innervation of human primary muscle cells, leading to complete differentiation and fiber contraction according to the method developed by Askanas2. To do so, muscle cells are co-cultured with spinal cord explants of rat embryos at ED 13.5, with the dorsal root ganglia still attached to the spinal cord slices. After a few days, the muscle fibers start to contract and eventually become cross-striated through innervation by functional neurites projecting from the spinal cord explants that connecting to the muscle cells. This structure can be maintained for many months, simply by regular exchange of the culture medium.
The applications of this invaluable tool are numerous, as it represents a functional model for multidisciplinary analyses of human muscle development and innervation. In fact, a complete de novo neuromuscular junction installation occurs in a culture dish, allowing an easy measurement of many parameters at each step, in a fundamental and physiological context.
Just to cite a few examples, genomic and/or proteomic studies can be performed directly on the co-cultures. Furthermore, pre- and post-synaptic effects can be specifically and separately assessed at the neuromuscular junction, because both components come from different species, rat and human, respectively. The nerve-muscle co-culture can also be performed with human muscle cells isolated from patients suffering from muscle or neuromuscular diseases3, and thus can be used as a screening tool for candidate drugs. Finally, no special equipment but a regular BSL2 facility is needed to reproduce a functional motor unit in a culture dish. This method thus is valuable for both the muscle as well as the neuromuscular research communities for physiological and mechanistic studies of neuromuscular function, in a normal and disease context.

Cultured muscle cells are an inadequate model to recapitulate innervated muscle in vivo. A functional motor unit can be reproduced in vitro by innervation of differentiated human primary muscle cells using rat embryo spinal cord explants. This article describes how co-cultures of spinal cord explants and muscle cells are established.

Un gruppo motore funzionale nella piastra di coltura: Co-coltura degli espianti midollo spinale e le cellule muscolari

Human primary muscle cells cultured  aneurally in monolayer rarely contract spontaneously because, in the absence of  a nerve component, cell ...

Assessing Neurodegenerative Phenotypes in Drosophila Dopaminergic Neurons by Climbing Assays and Whole Brain Immunostaining

Drosophila melanogaster is a valuable model organism to study aging and pathological degenerative processes in the nervous system. The advantages of the fly as an experimental system include its genetic tractability, short life span and the possibility to observe and quantitatively analyze complex behaviors. The expression of disease-linked genes in specific neuronal populations of the Drosophila brain, can be used to model human neurodegenerative diseases such as Parkinson's and Alzheimer's 5.
Dopaminergic (DA) neurons are among the most vulnerable neuronal populations in the aging human brain. In Parkinson's disease (PD), the most common neurodegenerative movement disorder, the accelerated loss of DA neurons leads to a progressive and irreversible decline in locomotor function. In addition to age and exposure to environmental toxins, loss of DA neurons is exacerbated by specific mutations in the coding or promoter regions of several genes. The identification of such PD-associated alleles provides the experimental basis for the use of Drosophila as a model to study neurodegeneration of DA neurons in vivo. For example, the expression of the PD-linked human &alpha;-synuclein gene in Drosophila DA neurons recapitulates some features of the human disease, e.g. progressive loss of DA neurons and declining locomotor function 2. Accordingly, this model has been successfully used to identify potential therapeutic targets in PD 8.
Here we describe two assays that have commonly been used to study age-dependent neurodegeneration of DA neurons in Drosophila: a climbing assay based on the startle-induced negative geotaxis response and tyrosine hydroxylase immunostaining of whole adult brain mounts to monitor the number of DA neurons at different ages. In both cases, in vivo expression of UAS transgenes specifically in DA neurons can be achieved by using a tyrosine hydroxylase (TH) promoter-Gal4 driver line 3, 10.

Assessing Neurodegenerative Phenotypes in Drosophila Dopaminergic Neurons by Climbing Assays and Whole Brain Immunostaining

Here we describe two assays that have been established to study age-dependent neurodegeneration of dopaminergic (DA) neurons in Drosophila: the climbing/startle-induced negative geotaxis assay which allows to study the functional effects of DA neurons degeneration and the tyrosine hydroxylase immunostaining which is used to identify and count DA neurons in whole brain mounts.

Valutare fenotipi neurodegenerative<em&gt; Drosophila</em&gt; Neuroni dopaminergici mediante saggi arrampicata e Whole Brain Immunostaining

Drosophila melanogaster is a valuable model organism to study aging and pathological degenerative processes in the nervous system. The advantages of the ...

Isolation and Quantification of Botulinum Neurotoxin From Complex Matrices Using the BoTest Matrix Assays

Accurate detection and quantification of botulinum neurotoxin (BoNT) in complex matrices is required for pharmaceutical, environmental, and food sample testing. Rapid BoNT testing of foodstuffs is needed during outbreak forensics, patient diagnosis, and food safety testing while accurate potency testing is required for BoNT-based drug product manufacturing and patient safety. The widely used mouse bioassay for BoNT testing is highly sensitive but lacks the precision and throughput needed for rapid and routine BoNT testing. Furthermore, the bioassay&#39;s use of animals has resulted in calls by drug product regulatory authorities and animal-rights proponents in the US and abroad to replace the mouse bioassay for BoNT testing. Several in vitro replacement assays have been developed that work well with purified BoNT in simple buffers, but most have not been shown to be applicable to testing in highly complex matrices. Here, a protocol for the detection of BoNT in complex matrices using the BoTest Matrix assays is presented. The assay consists of three parts: The first part involves preparation of the samples for testing, the second part is an immunoprecipitation step using anti-BoNT antibody-coated paramagnetic beads to purify BoNT from the matrix, and the third part quantifies the isolated BoNT&#39;s proteolytic activity using a fluorogenic reporter. The protocol is written for high throughput testing in 96-well plates using both liquid and solid matrices and requires about 2 hr of manual preparation with total assay times of 4-26 hr depending on the sample type, toxin load, and desired sensitivity. Data are presented for BoNT/A testing with phosphate-buffered saline, a drug product, culture supernatant, 2% milk, and fresh tomatoes and includes discussion of critical parameters for assay success.

The BoTest Matrix botulinum neurotoxin (BoNT) detection assays rapidly purify and quantify BoNT from a range of sample matrices.&#160;Here, we present a protocol for the detection and quantification of BoNT from both solid and liquid matrices and demonstrate the assay with BOTOX, tomatoes, and milk.

Isolamento e quantificazione della neurotossina botulinica da matrici complesse usando il BoTest Matrix saggi

Accurate detection and quantification of botulinum neurotoxin (BoNT) in complex matrices is required for pharmaceutical, environmental, and food sample ...

Primary Culture of Mouse Dopaminergic Neurons

Dopaminergic neurons represent less than 1% of the total number of neurons in the brain. This low amount of neurons regulates important brain functions such as motor control, motivation, and working memory. Nigrostriatal dopaminergic neurons selectively degenerate in Parkinson&#39;s disease (PD). This progressive neuronal loss is unequivocally associated with the motors symptoms of the pathology (bradykinesia, resting tremor, and muscular rigidity). The main agent responsible of dopaminergic neuron degeneration is still unknown. However, these neurons appear to be extremely vulnerable in diverse conditions. Primary cultures constitute one of the most relevant models to investigate properties and characteristics of dopaminergic neurons. These cultures can be submitted to various stress agents that mimic PD pathology and to neuroprotective compounds in order to stop or slow down neuronal degeneration. The numerous transgenic mouse models of PD that have been generated during the last decade further increased the interest of researchers for dopaminergic neuron cultures. Here, the video protocol focuses on the delicate dissection of embryonic mouse brains. Precise excision of ventral mesencephalon is crucial to obtain neuronal cultures sufficiently rich in dopaminergic cells to allow subsequent studies. This protocol can be realized with embryonic transgenic mice and is suitable for immunofluorescence staining, quantitative PCR, second messenger quantification, or neuronal death/survival assessment.

Dopaminergic neurons play a vital regulatory role in the brain. Their loss is associated with Parkinson's disease. In this video, we show how to generate primary cultures of central dopaminergic neurons from embryonic mouse mesencephalon. Such cultures are useful to study the extreme vulnerability of these neurons to various stresses.

Cultura primario di topo neuroni dopaminergici

Dopaminergic neurons represent less than 1% of the total number of neurons in the brain. This low amount of neurons regulates important brain functions ...

Long-term Time Lapse Imaging of Mouse Cochlear Explants

Here we present a method for long-term time-lapse imaging of live embryonic mouse cochlear explants. The developmental program responsible for building the highly ordered, complex structure of the mammalian cochlea proceeds for around ten days. In order to study changes in gene expression over this period and their response to pharmaceutical or genetic manipulation, long-term imaging is necessary. Previously, live imaging has typically been limited by the viability of explanted tissue in a humidified chamber atop a standard microscope. Difficulty in maintaining optimal conditions for culture growth with regard to humidity and temperature has placed limits on the length of imaging experiments. A microscope integrated into a modified tissue culture incubator provides an excellent environment for long term-live imaging. In this method we demonstrate how to establish embryonic mouse cochlear explants and how to use an incubator microscope to conduct time lapse imaging using both bright field and fluorescent microscopy to examine the behavior of a typical embryonic day (E) 13 cochlear explant and Sox2, a marker of the prosensory cells of the cochlea, over 5 days.

Live imaging of the embryonic mammalian cochlea is challenging because the developmental processes at hand operate on a temporal gradient over ten days. Here we present a method for culturing and then imaging embryonic cochlear explant tissue taken from a fluorescent reporter mouse over five days.

A lungo termine Time Lapse Imaging del mouse cocleari Espianti

Here we present a method for long-term time-lapse imaging of live embryonic mouse cochlear explants. The developmental program responsible for building ...

Protocol for Three-dimensional Confocal Morphometric Analysis of Astrocytes

As glial cells in the brain, astrocytes have diverse functional roles in the central nervous system. In the presence of harmful stimuli, astrocytes modify their functional and structural properties, a condition called reactive astrogliosis. Here, a protocol for assessment of the morphological properties of astrocytes is presented. This protocol includes quantification of 12 different parameters i.e. the surface area and volume of the tissue covered by an astrocyte (astrocyte territory), the entire astrocyte including branches, cell body, and nucleus, as well as total length and number of branches, the intensity of fluorescence immunoreactivity of antibodies used for astrocyte detection, and astrocyte density (number/1,000 &#181;m2). For this purpose three-dimensional (3D) confocal microscopic images were created, and 3D image analysis software such as Volocity 6.3 was used for measurements. Rat brain tissue exposed to amyloid beta1-40 (A&#946;1-40) with or without a therapeutic&#160;intervention was used to present the method. This protocol can also be used for 3D morphometric analysis of other cells from either in vivo or in vitro conditions.

Astrocytes in the CNS change their functional and structural properties in response to harmful stimuli. This report presents a protocol for assessment of three-dimensional astrocyte morphology in diseased conditions or after therapeutic interventions.

Protocollo per tridimensionale confocale morfometrica Analisi di astrociti

As glial cells in the brain, astrocytes have diverse functional roles in the central nervous system. In the presence of harmful stimuli, astrocytes modify ...

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex (pre-SMA and SMA proper) using a combination of fiber dissection techniques on cadaveric specimens and magnetic resonance (MR) tractography. The protocol will also describe the procedure for a white matter dissection of a human brain, diffusion tensor tractography imaging, and three-dimensional documentation. The fiber dissections on human brains and the 3D documentation were performed at the University of Minnesota, Microsurgery and Neuroanatomy Laboratory, Department of Neurosurgery. Five postmortem human brain specimens and two whole heads were prepared in accordance with Klingler's method. Brain hemispheres were dissected step by step from lateral to medial and medial to lateral under an operating microscope, and 3D images were captured at every stage. All dissection results were supported by diffusion tensor imaging. Investigations on the connections in line with Meynert's fiber tract classification, including association fibers (short, superior longitudinal fasciculus I and frontal aslant tracts), projection fibers (corticospinal, claustrocortical, cingulum, and frontostriatal tracts), and commissural fibers (callosal fibers) were also conducted.

The purpose of this study is to show each step of the fiber dissection technique on human cadaveric brains, the 3D documentation of these dissections, and the diffusion tensor imaging of the anatomically dissected fiber pathways.

Connessioni a fibre della zona motori aggiuntiva Revisited: Metodologia della discizione a fibre, DTI e documentazione tridimensionale

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex ...

Stereotaxic Surgery for Genetic Manipulation in Striatal Cells of Neonatal Mouse Brains

Many genes are expressed in embryonic brains, and some of them are continuously expressed in the brain after birth. For such persistently expressed genes, they may function to regulate the developmental process and/or physiological function in neonatal brains. To investigate neurobiological functions of specific genes in the brain, it is essential to inactivate genes in the brain. Here, we describe a simple stereotaxic method to inactivate gene expression in the striatum of transgenic mice at neonatal time windows. AAV-eGFP-Cre viruses were microinjected into the striatum of Ai14 reporter gene mice at postnatal day (P) 2 by stereotaxic brain surgery. The tdTomato reporter gene expression was detected in P14 striatum, suggesting a successful Cre-loxP mediated DNA recombination in AAV-transduced striatal cells. We further validated this technique by microinjecting AAV-eGFP-Cre viruses into P2Foxp2fl/fl mice. Double labeling of GFP and Foxp2 showed that GFP-positive cells lacked Foxp2 immunoreactivity in P9 striatum, suggesting the loss of Foxp2 protein in AAV-eGFP-Cre transduced striatal cells. Taken together, these results demonstrate an effective genetic deletion by stereotaxically microinjected AAV-eGFP-Cre viruses in specific neuronal populations in the neonatal brains of floxed transgenic mice. In conclusion, our stereotaxic technique provides an easy and simple platform for genetic manipulation in neonatal mouse brains. The technique can not only be used to delete genes in specific regions of neonatal brains, but it also can be used to inject pharmacological drugs, neuronal tracers, genetically modified optogenetics and chemogenetics proteins, neuronal activity indicators and other reagents into the striatum of neonatal mouse brains.

We describe a protocol of stereotaxic surgery with a homemade head-fixed device for microinjecting reagents into the striatum of neonatal mouse brains. This technique allows genetic manipulation in neuronal cells of specific regions of neonatal mouse brains.

Chirurgia stereotassica per la manipolazione genetica in cellule striatali di cervelli di topo neonatale

Many genes are expressed in embryonic brains, and some of them are continuously expressed in the brain after birth. For such persistently expressed genes, ...