Name: a microbiomechanical system for studying varicosity formation and recovery in central neuron axons
Uploaded: 2018-04-30T13:00:00
Description: Watch this Scientific Journal Video about A Microbiomechanical System for Studying Varicosity Formation and Recovery in Central Neuron Axons at JoVE.com

Alle Tierversuche wurden in Übereinstimmung mit den nationalen Institute der Gesundheit Tier Verwendung Richtlinien durchgeführt. Diese Arbeit wurde zum Teil durch Zuschüsse aus dem National Institutes of Health (R01NS093073 und R21AA024873), C. Gu unterstützt.

Alle nachfolgend beschriebene Methoden wurden von den institutionellen Animal Care und Nutzung Committee (IACUC) von der Ohio State University genehmigt.
(1) Deckglas Vorbereitung
<ol><li>Legen Sie einen oder mehrere Kisten mit 12 mm oder 25 mm Deckgläsern in ein Becherglas mit 70 % Salpetersäure und inkubieren Sie Deckgläsern bei Raumtemperatur über Nacht. Hinweis: Waschen Sie die 25 mm Deckgläsern im gleichen Becher als 12 mm Deckgläsern nicht. Es ist besser, sie separat zu wasche...

<ol>
	<li>Niki&#263;, I., 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+reversible+form+of+axon+damage+in+experimental+autoimmune+encephalomyelitis+and+multiple+sclerosis.">A reversible form of axon damage in experimental autoimmune encephalomyelitis and multiple sclerosis.</a> Nat. Med. 17, 495-499 (2011).</li><li>Yang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+axon+degeneration+after+injury+and+in+development+by+the+endogenous+calpain+inhibitor+calpastatin.">Regulation of axon degeneration after injury and in development by the endogenous calpain inhibitor calpastatin.</a> Neuron. 80 (5), 1175-1189 (2013).</li><li>Debanne, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Information+processing+in+the+axon.">Information processing in the axon.</a> Nat. Rev. Neurosci. 5, 304-316 (2004).</li><li>Gu, Y., Jukkola, P., Wang, Q., Esparza, T., Zhao, Y., Brody, D., Gu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polarity+of+varicosity+initiation+in+central+neuron+mechanosensation.">Polarity of varicosity initiation in central neuron mechanosensation.</a> J Cell Biol. 216 (7), 2179-2199 (2017).</li><li>Chung, R. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mild+axonal+stretch+injury+in+vitro+induces+a+progressive+series+of+neurofilament+alterations+ultimately+leading+to+delayed+axotomy.">Mild axonal stretch injury in vitro induces a progressive series of neurofilament alterations ultimately leading to delayed axotomy.</a> J. Neurotrauma. 22 (10), 1081-1091 (2005).</li><li>Staal, J. A., Dickson, T. C., Chung, R. S., Vickers, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyclosporin-A+treatment+attenuates+delayed+cytoskeletal+alterations+and+secondary+axotomy+following+mild+axonal+stretch+injury.">Cyclosporin-A treatment attenuates delayed cytoskeletal alterations and secondary axotomy following mild axonal stretch injury.</a> Dev. Neurobiol. 67 (14), 1831-1842 (2007).</li><li>Tang-Schomer, M. D., Johnson, V. E., Baas, P. W., Stewart, W., Smith, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+interruption+of+axonal+transport+due+to+microtubule+breakage+accounts+for+the+formation+of+periodic+varicosities+after+traumatic+axonal+injury.">Partial interruption of axonal transport due to microtubule breakage accounts for the formation of periodic varicosities after traumatic axonal injury.</a> Exp. Neurol. 233 (1), 364-372 (2012).</li><li>Donkin, J. J., Vink, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+cerebral+edema+in+traumatic+brain+injury:+therapeutic+developments.">Mechanisms of cerebral edema in traumatic brain injury: therapeutic developments.</a> Curr Opin Neurol. 23 (3), 293-299 (2010).</li><li>Gardner, A., Jukkola, P., Gu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myelination+of+rodent+hippocampal+neurons+in+culture.">Myelination of rodent hippocampal neurons in culture.</a> Nat Protoc. 7 (10), 1774-1782 (2012).</li><li>Wang, Q., Zhang, X., Zhao, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micromechanical+stimulator+for+localized+cell+loading:+fabrication+and+strain+analysis.">Micromechanical stimulator for localized cell loading: fabrication and strain analysis.</a> J. Micromech. Microeng. 23, 015002 (2013).</li><li>Lu, Y. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viscoelastic+properties+of+individual+glial+cells+and+neurons+in+the+CNS.">Viscoelastic properties of individual glial cells and neurons in the CNS.</a> Proc. Natl. Acad. Sci. USA. 103 (47), 17759-17764 (2006).</li><li>Elkin, B. S., Azeloglu, E. U., Costa, K. D., Morrison, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+heterogeneity+of+the+rat+hippocampus+measured+by+atomic+force+microscope+indentation.">Mechanical heterogeneity of the rat hippocampus measured by atomic force microscope indentation.</a> J. Neurotrauma. 24 (5), 812-822 (2007).</li><li>Franze, 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=Neurite+branch+retraction+is+caused+by+a+threshold-dependent+mechanical+impact.">Neurite branch retraction is caused by a threshold-dependent mechanical impact.</a> Biophys. J. 97 (7), 1883-1890 (2009).</li><li>Camp&#224;s, O., 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=Quantifying+cell-generated+mechanical+forces+within+living+embryonic+tissues.">Quantifying cell-generated mechanical forces within living embryonic tissues.</a> Nat. Methods. 11 (2), 183-189 (2014).</li></ol>

Das Verfahren des Microbiomechanical Assays ist geradlinig. Es werden zuverlässige Ergebnisse produzieren, wenn alle seine Schritte sorgfältig durchgeführt werden. Es gibt mehrere wichtige Schritte, die, wenn nicht ordnungsgemäß durchgeführt, erfolgreiche Datenerfassung behindern. Die entscheidenden Schritte beginnen oberhalb der tatsächlichen Anwendung des puffing Stimulus. Sorgfältige Dissektion, Kultivierung und Pflege der primäre Neuron Kultur im Vordergrund stehen. Wenn die kultivierten Neuronen nicht gesun...

Varizen-Bildung oder Schwellung/Sicke, entlang der Axone, ist ein hervorstechendes Merkmal der Neurodegeneration bei vielen Erkrankungen oder Verletzungen des zentralen Nervensystems, einschließlich multipler Sklerose, Morbus Alzheimer, Morbus Parkinson, beobachtet und traumatischen Gehirn Verletzungen1,2. Trotz der erheblichen physiologischen Auswirkungen der axonalen Krampfadern auf Aktionspotential Ausbreitung und die synaptische Übertragung3wie die Krampfadern entstehen, bleibt unbekannt. Vor kurzem, mit einer neu gegründeten Microbiomechanical-Assay auf kultivierten hippocampal Neuronen von Nagetieren, fanden wir, dass mechanische Reize Krampfadern in diesen Neuronen mit höchst faszinierende Funktionen hervorrufen können. Erstens Varizen Induktion ist schnell (< 10 s) und dieser Prozess kann unerwartet rückgängig gemacht werden. Zweitens, Varizen Einleitung hängt von der Stärke schnaufend Druck: je höher der Druck, desto schneller die Einleitung. Varizen Einleitung hängt Drittens neuronalen Alter. Die Axone der jüngere Neuronen scheinen stärker auf die mechanische Beanspruchung im Vergleich zu älteren Neuronen. Vierter, Krampfadern Form entlang der Axone hippocampal Neuronen, während die Dendriten und erste Axon Segmente dieser Neuronen zeigen keine Veränderung unter den gleichen Bedingungen, puffing. So, unsere Studie ergab ein Novum der neuronale Polarität. Diese Erkenntnisse mit dem in-vitro- System sind physiologisch relevanten. Eine in Vivo Modell zeigten für milde traumatische Hirnverletzungen (mTBI) wir, dass axonale Krampfadern in einer Multi-focal Mode im somatosensorischen Cortex der Mäuse, sofort nach dem Schließen-Totenkopf Aufprall, Einklang mit unserem in-vitro entwickelt- Ergebnisse4. Es ist wichtig zu beachten, dass unsere Färbung und Bildgebung der mTBI Mäuse nur eine Momentaufnahme der neuronalen morphologische Veränderungen, seit Durchführung in Vivo Zeitraffer Bildgebung der neuronale Morphologie während eine mechanische Wirkung ist noch nicht möglich.
Diese Flüssigkeit schnaufend System erlaubt uns nicht nur einzigartige Eigenschaften zu mechanischen Stress-induzierte Varizen-Bildung zu erfassen, sondern auch den zugrunde liegende Mechanismus zu bestimmen. Durch das Testen verschiedener extrazellulären Lösungen, Blocker und Öffner der verschiedenen Kandidaten der Mechanosensitive Ionenkanäle und zelluläre Elektrophysiologie, festgestellt wir, dass die Transienten Rezeptor potenzielle kation Kanal Unterfamilie V Bauteil 4 (TRPV4) Kanal, der ist durchlässig für Ca2 + und Na+ und aktiviert durch schnaufend ist hauptverantwortlich für die erste mechanischen Beanspruchung während der axonalen Varizen Bildung4erkennen. Dies wurde noch mit einem SiRNA ko Ansatz bestätigt. Zusammengenommen, diesem neuen Testsystem, die wir mit hippocampal Neuronen Kultur entwickelt haben, ist sehr wertvoll für die Mikromechanische Eigenschaften des zentralen Neuronen, vor allem in Kombination mit anderen Techniken zu studieren.
Dieses mikromechanische System, die, das wir eingerichtet haben, ist einzigartig und unterscheidet sich von den bereits bestehenden Systemen in einigen wichtigen Aspekten. Zuerst erleben die Neuronen in diesem System Out-of-Plane mechanischen Beanspruchung in den Formen der Kompression und Scheren. Während die mechanischen Auswirkungen neuronale Prozesse bleiben an der Oberfläche Deckglas und bewegen sich nicht. Dies unterscheidet sich von anderen experimentellen Systemen, die vor allem bücken und Strecken in der Ebene beteiligt (oder Spannung), zum Beispiel die Durchbiegung der gebündelte Axone wie Saiten5,6 verschieben oder dehnen Axone auf Micropatterned gewachsen Kanäle und dehnbare Membranen7,8. Darüber hinaus obwohl axonale Krampfadern auch in induziert werden können diese Tests wie in unserem Flüssigkeit schnaufend System, den Prozess in diesen Einstellungen dauert viel länger (ab 10 min bis mehreren Stunden6,7,8) und erscheint irreversible. Zu guter Letzt unser System mit lokalen Fluid schnaufend ermöglicht die Untersuchung der räumlichen Eigenschaften der Varizen-Bildung (zB., Dendriten, dendritische Dornen, Soma, axonalen ersten Segmente axonalen Klemmen), neben seiner zeitlichen Eigenschaften. Mit diesem System haben wir mehrere unerwartete und einzigartige Eigenschaften der axonalen Varizen-Bildung, vor allem schnellen Wirkungseintritt langsam Reversibilität und Axon-Dendrit Polarität entdeckt.
Das System, das wir in diesem Papier zu diskutieren ist kompatibel mit vielen Techniken der molekularen und Zellbiologie. Zum Beispiel zur Untersuchung der Auswirkungen von mechanischem Stress auf neuronale Morphologie und Funktion zusammen mit Myelin Coculture, Time-Lapse Bildgebung des Fluoreszenz Resonanz Energietransfer (FRET) und Totalreflexion Fluoreszenz (TIRF) einsetzbar Calcium Imaging und Patch-Clamp-Aufnahme. In diesem Artikel konzentrieren wir uns auf den Kern-Komponenten des Systems. Hippocampal Neuronen Kultur, die Flüssigkeit schnaufend Setup, hochauflösender Zeitraffer Imaging für axonalen Transport und Kalzium Imaging werden Schritt für Schritt unten illustriert.

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			<td height="40" style="height:40px;width:341px;">12 mm coverslips&#160;</td>
			<td style="width:139px;">Warner Instruments&#160;</td>
			<td style="width:119px;">64-0702</td>
			<td style="width:167px;">for 24-well plate&#160;</td>
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		<tr height="40">
			<td height="40" style="height:40px;">25 mm coverslips&#160;</td>
			<td>Fisher Scientific&#160;</td>
			<td>12-545-102&#160;</td>
			<td>for 6-well plate&#160;</td>
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			<td height="40" style="height:40px;">Acetic acid</td>
			<td>Fisher Scientific&#160;</td>
			<td>A38-212</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Poly-D-lysine</td>
			<td>Sigma&#160;</td>
			<td>P6407</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Rat tail collagen&#160;</td>
			<td>Roche&#160;</td>
			<td>11 179 179 001&#160;</td>
			<td></td>
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			<td height="40" style="height:40px;">10X PBS&#160;</td>
			<td>National Diagnostics&#160;</td>
			<td>CL-253</td>
			<td></td>
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			<td align="left" height="40" style="height:40px;">Na2SO4</td>
			<td>Fisher Scientific&#160;</td>
			<td>S373-500</td>
			<td></td>
		</tr>
		<tr height="40">
			<td align="left" height="40" style="height:40px;">K2SO4</td>
			<td>Fisher Scientific&#160;</td>
			<td>P304-500</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">HEPES&#160;</td>
			<td>Fisher Scientific&#160;</td>
			<td>BP410-500</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">D-glucose&#160;</td>
			<td>Fisher Scientific&#160;</td>
			<td>D16-500</td>
			<td></td>
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		<tr height="40">
			<td align="left" height="40" style="height:40px;">MgCl2</td>
			<td>Fisher Scientific&#160;</td>
			<td>BP214-500</td>
			<td></td>
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		<tr height="40">
			<td height="40" style="height:40px;">NaOH</td>
			<td>Fisher Scientific&#160;</td>
			<td>SS255-1</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Protease enzyme&#160;</td>
			<td>Sigma&#160;</td>
			<td>P4032</td>
			<td></td>
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		<tr height="40">
			<td height="40" style="height:40px;">FBS</td>
			<td>Gibco&#160;</td>
			<td>26140</td>
			<td></td>
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		<tr height="40">
			<td height="40" style="height:40px;">Sodium pyruvate&#160;</td>
			<td>Gibco&#160;</td>
			<td>11360-070</td>
			<td></td>
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			<td height="40" style="height:40px;">L-glutamine&#160;</td>
			<td>Gibco&#160;</td>
			<td>25030081</td>
			<td></td>
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			<td height="40" style="height:40px;">Penicillin/Streptomycin 100x (P/S)</td>
			<td>Gibco&#160;</td>
			<td style="width:119px;">15140122</td>
			<td></td>
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		<tr height="40">
			<td height="40" style="height:40px;">MEM Earle&#39;s Salts&#160;</td>
			<td>Gibco&#160;</td>
			<td>11090</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">B27 supplement&#160;</td>
			<td>Gibco&#160;</td>
			<td>17504-044</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Neurobasal&#160;</td>
			<td>Gibco&#160;</td>
			<td>21103-049</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Arabinosylcytosine (Ara-C)</td>
			<td>Sigma&#160;</td>
			<td>147-94-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Opti-MEM media&#160;</td>
			<td>Gibco&#160;</td>
			<td>31985-070</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lipofectamine 2000</td>
			<td>Invitrogen&#160;</td>
			<td>1854313</td>
			<td>transfection reagent&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Borosilicate rods&#160;</td>
			<td>World Precision Instruments Inc.&#160;</td>
			<td>PG52151-4</td>
			<td>for puffing pipette&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">rubber tubing&#160;</td>
			<td style="width:139px;">Fisher Scientific&#160;</td>
			<td style="width:119px;">14-169-1A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">10cc plastic syringe and plunger</td>
			<td>Becton Dickinson&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">micromanipulator&#160;</td>
			<td>Sutter Instruments&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NaCl&#160;</td>
			<td>Fisher Scientific&#160;</td>
			<td>S640-3</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">KCl&#160;</td>
			<td>Fisher Scientific&#160;</td>
			<td>BP366-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td align="left" height="21" style="height:21px;">CaCl2</td>
			<td>Fisher Scientific&#160;</td>
			<td>C70-500</td>
			<td></td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;width:341px;">Cell culture dish (35 mm x 10 mm)</td>
			<td style="width:139px;">Corning&#160;</td>
			<td style="width:119px;">3294</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Fluo-4 AM</td>
			<td style="width:139px;">Molecular Probes</td>
			<td style="width:119px;">F14201</td>
			<td style="width:167px;">for calcium imaging&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Mito-YFP construct&#160;</td>
			<td style="width:139px;">Takara Bio Inc.&#160;</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">for cell transfection&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">YFP-N1 construct&#160;</td>
			<td style="width:139px;">Takara Bio Inc.&#160;</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">for cell transfection&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Model P-1000 Flaming/Brown Micropipette puller&#160;</td>
			<td style="width:139px;">Sutter Instruments&#160;</td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Eclipse TE2000-U Mcroscope&#160;</td>
			<td style="width:139px;">Nikon</td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Plan Fluor ELWD 20x lens&#160;&#160;</td>
			<td style="width:139px;">Nikon</td>
			<td style="width:119px;">062933</td>
			<td style="width:167px;">objective&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Apo TIRF 100x/1.49 oil lens&#160;</td>
			<td style="width:139px;">Nikon</td>
			<td style="width:119px;">MRD01991</td>
			<td style="width:167px;">objective&#160;</td>
		</tr>
	</tbody>
</table>

a microbiomechanical system for studying varicosity formation and recovery in central neuron axons

Axonale Krampfadern sind erweiterte Strukturen entlang der Wellen von Axonen mit ein hohes Maß an Heterogenität. Sie sind nicht nur im Gehirn mit neurodegenerativen Erkrankungen oder Verletzungen, sondern auch im normalen Gehirn. Hier beschreiben wir eine neu gegründete mikromechanische System, schnell, zuverlässig und reversibel axonale Krampfadern, induzieren, ermöglicht es uns, die EZB, Varizen-Bildung und heterogenen Proteinzusammensetzung Mechanismen zu verstehen. Dieses System stellt eine neuartige Mittel zur Bewertung der Auswirkungen von Kompression und Shear Stress auf verschiedenen subzelluläre Kompartimente von Neuronen, anders als andere in-vitro- Systeme, die sich hauptsächlich auf die Wirkung von stretching. Vor allem aufgrund der einzigartigen Merkmale unseres Systems haben wir vor kurzem eine neuartige Entdeckung zeigt, dass die Anwendung der unter Druck stehende Flüssigkeit schnell und reversibel axonale Krampfadern durch die Aktivierung eines Transienten Rezeptor potenzielle Kanals hervorrufen kann. Unsere biomechanische System kann bequem in Kombination mit Medikamenten Perfusion, live Cell Imaging, Kalzium Bildgebung und Patch-Clamp-Aufnahme genutzt werden. Daher kann diese Methode für das Studium Mechanosensitive Ionenkanäle, axonalen Transport Verordnung axonalen Zytoskelett Dynamik, Kalzium-Signalisierung und morphologische Veränderungen im Zusammenhang mit traumatischen Hirnverletzungen übernommen werden.

Vor schnaufend, zeigen Axone normalerweise kleine Varizen-Bildung. Folgenden schnaufend mit unseren Normdruck (190 MmH2O Höhe), die Axone Start viele Perlen-wie Krampfadern entwickeln. Die Bildung von Krampfadern ist teilweise reversibel, dargestellt durch Regionen des Axons Rückkehr in ihre bereits aufgeblasen Zustand nach einer 10 Minuten Erholungszeit (Abbildung 2A-B). Nach längerer Zeit der Erholung (> 20 min), einige Axone ...

Watch this Scientific Journal Video about A Microbiomechanical System for Studying Varicosity Formation and Recovery in Central Neuron Axons at JoVE.com

A Microbiomechanical System for Studying Varicosity Formation and Recovery in Central Neuron Axons

Dieses Protokoll beschreibt eine physiologisch relevante, unter Druck stehende flüssige Ansatz für schnelle und reversible Induktion von Krampfadern in den Neuronen.

Ein Microbiomechanical-System für das Studium Varizen-Bildung und Erholung in zentralen Neuronen Axone

Axonal varicosities are enlarged structures along the shafts of axons with a high degree of heterogeneity. They are present not only in brains with ...

The overall goal of this pressurized fluid setup is to produce repeatable and consistent swellings along the axons of cultured neurons. This method can help answer key questions in the brain injury field such as the mechanisms behind subcellular morphological changes in neurons following injury. The main advantage of this technique is that the method produces consistent and repeatable morphological changes that recover over time.This is very important technique we developed in the lab. This is because we can not only use the system to identify molecular mechanism governing mechanical-stress-induced axon morphology change as a new form of neuronal plasticity, but also use the system as a screening tool to identify new drugs and the treatment strategy for mild or traumatic brain injury. To begin this procedure, place one or more boxes of 12-millimeter or 25-millimeter coverslips into a glass beaker containing 70%nitric acid, and incubate the coverslips at room temperature overnight.The next day, transfer all coverslips into a four-liter beaker filled with 2.5 liters of double-distilled water. Shake the beaker containing the coverslips for one hour at 100 RPM, and don't forget to use rubber bands to hold the beaker during shaking. Subsequently, transfer the cleaned coverslips to a dry flask with the metal cover.Bake the coverslips in an oven at 225 degrees Celsius for six hours. Then, allow them to cool to room temperature and store them in a sterilized plastic container until usage. Now, place one coverslip into each well of a 24-well plate.Add 30 microliters of coverslip coating solution onto a 12-millimeter coverslip and swirl. Afterward, add one milliliter of sterile PBS to each well. The plate can be either used immediately or stored at four degrees Celsius in sterile PBS for up to one week.On the day of dissection, remove PBS from the plate. Air dry and place the plate under UV light for two to four hours. To dissociate the hippocampal neurons for culture, thaw the protease enzyme solution and pre-warm the plating medium at 37 degrees Celsius.Next, rinse the dissected hippocampus with SLDS. Then, remove it and add two milliliters of protease enzyme solution and incubate the sample at 37 degrees Celsius for 15 minutes. Afterward, wash the hippocampus explants with five to 10 milliliters of plating medium twice and add five milliliters of plating medium.Dissociate the hippocampal explants into single cells by generating a small vortex using a pipette with a one-milliliter plastic tip. Pipette up and down about 40 times avoiding the formation of oxygen bubbles until the solution becomes cloudy and no large pieces of explant remain. Next, centrifuge the cells at 1, 125 times gravity for three minutes.Remove the supernatant with the cells submerged in medium and re-suspend the cells in 145 milliliters of plating medium. Then, add one milliliter of the cell suspension per well to a 24-well plate. Incubate the cells in the plating medium at 37 degrees Celsius for two to four hours.Afterward, remove the plating medium and replace it with fresh maintenance medium. After two days, replace half of the medium with two micromolar RSC dissolved in maintenance medium to inhibit growth of fibroblast, endothelial and glial cells. Then, after exposing the cells to RSC for two days, replace the medium with fresh maintenance medium.To transfect for the visualization of cell morphology, dilute the construct from stock at one microgram per microliter in Opti-MEM medium and vortex. Then, dilute liposome-mediated transfection reagent in Opti-MEM media and vortex. Subsequently, prepare one construction dilution and one transfection dilution for each well.Next, prepare a one-to-one mixture of the construct and Opti-MEM medium and transfection reagent and Opti-MEM medium and vortex. Incubate the mixture at room temperature for 20 minutes. After 20 minutes, remove half of the medium from each well and transfer this medium into a clean conical tube.Keep the tube in the incubator, then add 100 microliters of the mixture prepared in the previous step to the remaining medium in the well. Allow the cells to incubate at 37 degrees Celsius for 20 to 30 minutes. During incubation, add one volume of fresh maintenance medium to the medium in the conical tube and place the mixture in the same incubator.Following incubation, remove the mediums containing the transfection solution from the wells and replace it with the one-to-one mixture of old and fresh maintenance medium in the conical tube. In this procedure, insert the pipette into the screw top of the micromanipulator to hold it into place. Screw the metal flat-top screw attached to the micromanipulator arm so that it holds the unpulled end of the pipette just above where the rubber tubing is attached.Angle the pipette at a 45 degree angle with the surface of the neuron containing coverslips. Turn on the florescence filter. Open the aperture, and ensure a fluorescent spot can be seen coming through the objective.Using the micromanipulator, move the pipette into a position that lines up the tip with the fluorescent spot and lower the pipette into a position just above the height of the cell culture dish. Once it is in position, turn on the transmitted light and turn off the florescence. Using tweezers, transfer one coverslip with the cells facing toward the pipette from the cell culture plate to the cell culture dish containing 2 milliliters of Hank's buffer at room temperature.Using the fine focus knob and 20 fold objective, focus on a plane about four full turns above the cells. Subsequently, use the micromanipulator to position the pipette tip so that it is focused and in the center left-hand side of the plane as seen through the eyepieces. Once the pipette is in position, focus the microscope on a plane that contains the region of interest.In the imaging of seven div, GFP transfected mouse hippocampal neurons showed an axon pre and post puffing, as well as a following 10 minute recovery period. Here is the Kymograph of time-lapse imaging of the same neuron. Red arrows indicate the varicosities that have formed to following 150 seconds of 190 milliliter H2O puffing, beginning at 30 seconds.Once mastered, this technique can be done in three hours if it is performed properly. Following this procedure, other methods like whole cell recording, time-lapse FRET and TIRF imaging, and calcium imaging can be performed in order to answer additional questions like the impacts of mechanical stress on neural and electrical and calcium signaling, protein trafficking and interactions. After its development, this technique paved the way for researchers in the photo traumatic brain injury to explain molecular mechanisms underlying axonal varicosity formation in living neurons.After watching this video, you should have a good understanding of how to perform the experiments to study mechanosensations of central neurons.

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Research

JoVE Journal

Neuroscience

Systemic and Local Drug Delivery for Treating Diseases of the Central Nervous System in Rodent Models

Thorough preclinical testing of central nervous system (CNS) therapeutics includes a consideration of routes of administration and agent biodistribution in assessing therapeutic efficacy. Between the two major classifications of administration, local vs. systemic, systemic delivery approaches are often preferred due to ease of administration. However, systemic delivery may result in suboptimal drug concentration being achieved in the CNS, and lead to erroneous conclusions regarding agent efficacy. Local drug delivery methods are more invasive, but may be necessary to achieve therapeutic CNS drug levels. Here, we demonstrate proper technique for three routes of systemic drug delivery: intravenous injection, intraperitoneal injection, and oral gavage. In addition, we show a method for local delivery to the brain: convection-enhanced delivery (CED). The use of fluorescently-labeled compounds is included for in vivo imaging and verification of proper drug administration. The methods are presented using murine models, but can easily be adapted for use in rats.

Thorough preclinical testing of drugs that act in the central nervous system often involves assessing and comparing drug biodistribution in association with specific routes of administration. Here, three commonly used methods of systemic delivery (intravenous, intraperitoneal, and oral) as well as a method for local delivery (convection-enhanced delivery) are demonstrated in mice.

Systemischen und lokalen Drug Delivery zur Behandlung von Erkrankungen des Zentralen Nervensystems in Nagermodellen

Thorough preclinical testing of central nervous system (CNS) therapeutics includes a consideration of routes of administration and agent biodistribution ...

Forschung

Neurowissenschaften

Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. 
The optic nerve can be accessed within the orbit of the eye and completely transected (axotomized), cutting the axons of the entire RGC population. Optic nerve 
transection is a reproducible model of apoptotic neuronal cell death in the adult CNS 1-4. This model is particularly attractive because the vitreous
 chamber of the eye acts as a capsule for drug delivery to the retina, permitting experimental manipulations via intraocular injections. The diffusion of chemicals 
through the vitreous fluid ensures that they act upon the entire RGC population. Moreover, RGCs can be selectively transfected by applying short interfering RNAs 
(siRNAs), plasmids, or viral vectors to the cut end of the optic nerve 5-7 or injecting vectors into their target, the superior colliculus 8. 
This allows researchers to study apoptotic mechanisms in the desired neuronal population without confounding effects on other bystander neurons or surrounding glia. 
An additional benefit is the ease and accuracy with which cell survival can be quantified after injury. The retina is a flat, layered tissue and RGCs are localized in 
the innermost layer, the ganglion cell layer. The survival of RGCs can be tracked over time by applying a fluorescent tracer (3% Fluorogold) to the cut end of the 
optic nerve at the time of axotomy, or by injecting the tracer into the superior colliculus (RGC target) one week prior to axotomy. The tracer is retrogradely transported, labeling 
the entire RGC population. Because the ganglion cell layer is a monolayer (one cell thick), RGC densities can be quantified in flat-mounted tissue, without the need 
for stereology. Optic nerve transection leads to the apoptotic death of 90% of injured RGCs within 14 days postaxotomy 9-11. RGC apoptosis has a 
characteristic time-course whereby cell death is delayed 3-4 days postaxotomy, after which the cells rapidly degenerate. This provides a time window for 
experimental manipulations directed against pathways involved in apoptosis.

Optic Nerve transection is a widely used model of adult CNS injury. Ninety percent of retinal ganglion cells (RGCs) whose axons are completely transected (axotomy) die within 14 days after axotomy. This model is easily amenable to experimental manipulations and highly reproducible.

Optic Nerve Durchtrennung: Ein Modell des Adult Neuron Apoptose in das zentrale Nervensystem

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. 
The optic nerve can be ...

Morphological Analysis of Drosophila Larval Peripheral Sensory Neuron Dendrites and Axons Using Genetic Mosaics

Nervous system development requires the correct specification of neuron position and identity, followed by accurate neuron class-specific dendritic development and axonal wiring. Recently the dendritic arborization (DA) sensory neurons of the Drosophila larval peripheral nervous system (PNS) have become powerful genetic models in which to elucidate both general and class-specific mechanisms of neuron differentiation.
There are four main DA neuron classes (I-IV)1. They are named in order of increasing dendrite arbor complexity, and have class-specific differences in the genetic control of their differentiation2-10. The DA sensory system is a practical model to investigate the molecular mechanisms behind the control of dendritic morphology11-13 because: 1) it can take advantage of the powerful genetic tools available in the fruit fly, 2) the DA neuron dendrite arbor spreads out in only 2 dimensions beneath an optically clear larval cuticle making it easy to visualize with high resolution in vivo, 3) the class-specific diversity in dendritic morphology facilitates a comparative analysis to find key elements controlling the formation of simple vs. highly branched dendritic trees, and 4) dendritic arbor stereotypical shapes of different DA neurons facilitate morphometric statistical analyses.
DA neuron activity modifies the output of a larval locomotion central pattern generator14-16. The different DA neuron classes have distinct sensory modalities, and their activation elicits different behavioral responses14,16-20. Furthermore different classes send axonal projections stereotypically into the Drosophila larval central nervous system in the ventral nerve cord (VNC)21. These projections terminate with topographic representations of both DA neuron sensory modality and the position in the body wall of the dendritic field7,22,23. Hence examination of DA axonal projections can be used to elucidate mechanisms underlying topographic mapping7,22,23, as well as the wiring of a simple circuit modulating larval locomotion14-17.
We present here a practical guide to generate and analyze genetic mosaics24 marking DA neurons via MARCM (Mosaic Analysis with a Repressible Cell Marker)1,10,25 and Flp-out22,26,27 techniques (summarized in Fig. 1).

Morphological Analysis of Drosophila Larval Peripheral Sensory Neuron Dendrites and Axons Using Genetic Mosaics

The dendritic arborization sensory neurons of the Drosophila larval peripheral nervous system are useful models to elucidate both general and neuron class-specific mechanisms of neuron differentiation. We present a practical guide to generate and analyze dendritic arborization neuron genetic mosaics.

Morphologische Analyse Drosophila Larven peripheren sensorischen Neuron Dendriten und Axone mit Genetic Mosaike

Nervous system development requires the correct specification of neuron position and identity, followed by accurate neuron class-specific dendritic ...

In ovo Electroporation in Chick Midbrain for Studying Gene Function in Dopaminergic Neuron Development

Dopaminergic neurons located in the ventral midbrain control movement, emotional behavior, and reward mechanisms1-3. The dysfunction of ventral midbrain dopaminergic neurons is implicated in Parkinson's disease, Schizophrenia, depression, and dementia1-5. Thus, studying the regulation of midbrain dopaminergic neuron differentiation could not only provide important insight into mechanisms regulating midbrain development and neural progenitor fate specification, but also help develop new therapeutic strategies for treating a variety of human neurological disorders.
Dopaminergic neurons differentiate from neural progenitors lining the ventricular zone of embryonic ventral midbrain. The development of neural progenitors is controlled by gene expression programs6,7. Here we report techniques utilizing electroporation to express genes specifically in the midbrain of Hamburger Hamilton (HH) stage 11 (thirteen somites, 42 hours) chick embryos8,9. The external development of chick embryos allows for convenient experimental manipulations at specific embryonic stages, with the effects determined at later developmental time points10-13. Chick embryonic neural tubes earlier than HH stage 13 (nineteen somites, 48 hours) consist of multipotent neural progenitors that are capable of differentiating into distinct cell types of the nervous system. The pCAG vector, which contains both a CMV promoter and a chick &beta;-actin enhancer, allows for robust expression of Flag or other epitope-tagged constructs in embryonic chick neural tubes14. In this report, we emphasize special measures to achieve regionally restricted gene expression in embryonic midbrain dopaminergic neuron progenitors, including how to inject DNA constructs specifically into the embryonic midbrain region and how to pinpoint electroporation with small custom-made electrodes. Analyzing chick midbrain at later stages provides an excellent in vivo system for plasmid vector-mediated gain-of-function and loss-of-function studies of midbrain development. Modification of the experimental system may extend the assay to other parts of the nervous system for performing fate mapping analysis and for investigating the regulation of gene expression.

In ovo Electroporation in Chick Midbrain for Studying Gene Function in Dopaminergic Neuron Development

To assess the function and the regulation of genes during the development of midbrain dopaminergic neurons, we describe a method that involves in ovo electroporation of plasmid DNA constructs into embryonic chick ventral midbrain dopaminergic neuron progenitors. This technique can be used to achieve efficient expression of genes of interest to study different aspects of midbrain development and dopaminergic neuron differentiation.

In ovo Elektroporation in Mittelhirn-Küken für Studien über Genfunktion in dopaminergen Neuronen Entwicklung

Dopaminergic neurons located in the ventral midbrain control movement, emotional behavior, and reward mechanisms1-3. The dysfunction of ventral midbrain ...

Production of Lentiviral Vectors for Transducing Cells from the Central Nervous System

Efficient gene delivery in the central nervous system (CNS) is important in studying gene functions, modeling neurological diseases and developing therapeutic approaches. Lentiviral vectors are attractive tools in transduction of neurons and other cell types in CNS as they transduce both dividing and non-dividing cells, support sustained expression of transgenes, and have relatively large packaging capacity and low toxicity 1-3. Lentiviral vectors have been successfully used in transducing many neural cell types in vitro 4-6 and in animals 7-10.
Great efforts have been made to develop lentiviral vectors with improved biosafety and efficiency for gene delivery. The current third generation replication-defective and self-inactivating (SIN) lentiviral vectors are depicted in Figure 1. The required elements for vector packaging are split into four plasmids. In the lentiviral transfer plasmid, the U3 region in the 5' long terminal repeat (LTR) is replaced with a strong promoter from another virus. This modification allows the transcription of the vector sequence independent of HIV-1 Tat protein that is normally required for HIV gene expression 11. The packaging signal (&Psi;) is essential for encapsidation and the Rev-responsive element (RRE) is required for producing high titer vectors. The central polypurine tract (cPPT) is important for nuclear import of the vector DNA, a feature required for transducing non-dividing cells 12. In the 3' LTR, the cis-regulatory sequences are completely removed from the U3 region. This deletion is copied to 5' LTR after reverse transcription, resulting in transcriptional inactivation of both LTRs. Plasmid pMDLg/pRRE contains HIV-1 gag/pol genes, which provide structural proteins and reverse transcriptase. pRSV-Rev encodes Rev which binds to the RRE for efficient RNA export from the nucleus. pCMV-G encodes the vesicular stomatitis virus glycoprotein (VSV-G) that replaces HIV-1 Env. VSV-G expands the tropism of the vectors and allows concentration via ultracentrifugation 13. All the genes encoding the accessory proteins, including Vif, Vpr, Vpu, and Nef are excluded in the packaging system. The production and manipulation of lentiviral vectors should be carried out according to NIH guidelines for research involving recombinant DNA (<a href="http://oba.od.nih.gov/oba/rac/Guidelines/NIH_Guidelines.pdf" target="_blank">http://oba.od.nih.gov/oba/rac/Guidelines/NIH_Guidelines.pdf</a>). An approval from individual Institutional Biological and Chemical Safety Committee may be required before using lentiviral vectors. Lentiviral vectors are commonly produced by cotransfection of 293T cells with lentiviral transfer plasmid and the helper plasmids encoding the proteins required for vector packaging. Many lentiviral transfer plasmids and helper plasmids can be obtained from Addgene, a non-profit plasmid repository (<a href="http://www.addgene.org/" target="_blank">http://www.addgene.org/</a>). Some stable packaging cell lines have been developed, but these systems provide less flexibility and their packaging efficiency generally declines over time 14, 15. Commercially available transfection kits may support high efficiency of transfection 16, but they can be very expensive for large scale vector preparations. Calcium phosphate precipitation methods provide highly efficient transfection of 293T cells and thus provide a reliable and cost effective approach for lentiviral vector production.
In this protocol, we produce lentiviral vectors by cotransfection of 293T cells with four plasmids based on the calcium phosphate precipitation principle, followed by purification and concentration with ultracentrifugation through a 20% sucrose cushion. The vector titers are determined by fluorescence- activated cell sorting (FACS) analysis or by real time qPCR. The production and titration of lentiviral vectors in this protocol can be finished with 9 days. We provide an example of transducing these vectors into murine neocortical cultures containing both neurons and astrocytes. We demonstrate that lentiviral vectors support high efficiency of transduction and cell type-specific gene expression in primary cultured cells from CNS.

In this protocol we describe production, purification and titration of lentiviral vectors. We provide an example of lentiviral vector-mediated gene delivery in primary cultured neurons and astrocytes. Our methods may also apply to other cell types in vitro and in vivo.

Die Produktion von lentiviralen Vektoren für die Transduktion von Zellen aus dem Zentralen Nervensystems

Efficient gene delivery in the central nervous system (CNS) is important in studying gene functions, modeling neurological diseases and developing ...

A Lightweight, Headphones-based System for Manipulating Auditory Feedback in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and sensorimotor plasticity1. Consistent sensory perturbations result in compensatory changes in motor output, reflecting changes in feedforward motor control that reduce the experienced feedback error. By quantifying how different sensory feedback errors affect human behavior, prior studies have explored how visual signals are used to recalibrate arm movements2,3 and auditory feedback is used to modify speech production4-7. The strength of this approach rests on the ability to mimic naturalistic errors in behavior, allowing the experimenter to observe how experienced errors in production are used to recalibrate motor output.
Songbirds provide an excellent animal model for investigating the neural basis of sensorimotor control and plasticity8,9. The songbird brain provides a well-defined circuit in which the areas necessary for song learning are spatially separated from those required for song production, and neural recording and lesion studies have made significant advances in understanding how different brain areas contribute to vocal behavior9-12. However, the lack of a naturalistic error-correction paradigm - in which a known acoustic parameter is perturbed by the experimenter and then corrected by the songbird - has made it difficult to understand the computations underlying vocal learning or how different elements of the neural circuit contribute to the correction of vocal errors13.
The technique described here gives the experimenter precise control over auditory feedback errors in singing birds, allowing the introduction of arbitrary sensory errors that can be used to drive vocal learning. Online sound-processing equipment is used to introduce a known perturbation to the acoustics of song, and a miniaturized headphones apparatus is used to replace a songbird's natural auditory feedback with the perturbed signal in real time. We have used this paradigm to perturb the fundamental frequency (pitch) of auditory feedback in adult songbirds, providing the first demonstration that adult birds maintain vocal performance using error correction14. The present protocol can be used to implement a wide range of sensory feedback perturbations (including but not limited to pitch shifts) to investigate the computational and neurophysiological basis of vocal learning.

We describe the design and assembly of miniaturized headphones suitable for replacing a songbird&#x2019;s natural auditory feedback with a manipulated acoustic signal. Online sound processing hardware is used to manipulate song output, introduce real-time errors in auditory feedback via the headphones, and drive vocal motor learning.

Ein Leichtes, Kopfhörer-basierte System zur Manipulation Auditory Feedback in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and ...

Direct Intraventricular Delivery of Drugs to the Rodent Central Nervous System

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses specifically on antisense oligonucleotides (ASOs), though the techniques shown in the video here can also be used to deliver a plethora of other drugs to the CNS. Antisense oligonucleotides (ASOs) have the capability to knockdown sequence-specific targets 1 as well as shift isoform ratios of specific genes 2. To achieve widespread gene knockdown or splicing in the CNS of mice, the ASOs can be delivered into the brain using two separate routes of administration, both of which we demonstrate in the video.
The first uses Alzet osmotic pumps, connected to a catheter that is surgically implanted into the lateral ventricle. This allows the ASOs to be continuously infused into the CNS for a designated period of time. The second involves a single bolus injection of a high concentration of ASO into the right lateral ventricle. Both methods use the mouse cerebral ventricular system to deliver the ASO to the entire brain and spinal cord, though depending on the needs of the study, one method may be preferred over the other.

We describe a method to target drugs to the central nervous system by either implanting a catheter or performing a bolus injection into the right lateral ventricle in mice. We focus specifically on the delivery of antisense oligonucleotides. This technique is readily adaptable to other drugs and to rats.

Direkt Intraventrikuläre Abgabe von Arzneimitteln an die Nager Central Nervous System

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses ...

Immunohistochemical Analysis in the Rat Central Nervous System and Peripheral Lymph Node Tissue Sections

Immunohistochemistry (IHC) provides highly specific, reliable and attractive protein visualization. Correct performance and interpretation of an IHC-based multicolor labeling is challenging, especially when utilized for assessing interrelations between target proteins in the tissue with a high fat content such as the central nervous system (CNS).
Our protocol represents a refinement of the standard immunolabeling technique particularly adjusted for detection of both structural and soluble proteins in the rat CNS and peripheral lymph nodes (LN) affected by neuroinflammation. Nonetheless, with or without further modifications, our protocol could likely be used for detection of other related protein targets, even in other organs and species than here presented.

We here present an optimized, detailed protocol for double immunostaining in formalin-fixed, paraffin-embedded rat central nervous system (CNS) and peripheral lymph node (LN) tissue sections.

Immunhistochemische Analyse im Rat des Zentralnervensystems und peripheren Lymphknoten Gewebeschnitte

Immunohistochemistry (IHC) provides highly specific, reliable and attractive protein visualization. Correct performance and interpretation of an IHC-based ...

Laser Nanosurgery of Cerebellar Axons In Vivo

Only a few neuronal populations in the central nervous system (CNS) of adult mammals show local regrowth upon dissection of their axon. In order to understand the mechanism that promotes neuronal regeneration, an in-depth analysis of the neuronal types that can remodel after injury is needed. Several studies showed that damaged climbing fibers are capable of regrowing also in adult animals1,2. The investigation of the time-lapse dynamics of degeneration and regeneration of these axons within their complex environment can be performed by time-lapse two-photon fluorescence (TPF) imaging in vivo3,4. This technique is here combined with laser surgery, which proved to be a highly selective tool to disrupt fluorescent structures in the intact mouse cortex5-9.
This protocol describes how to perform TPF time-lapse imaging and laser nanosurgery of single axonal branches in the cerebellum in vivo. Olivocerebellar neurons are labeled by anterograde tracing with a dextran-conjugated dye and then monitored by TPF imaging through a cranial window. The terminal portion of their axons are then dissected by irradiation with a Ti:Sapphire laser at high power. The degeneration and potential regrowth of the damaged neuron are monitored by TPF in vivo imaging during the days following the injury.

Laser Nanosurgery of Cerebellar Axons In Vivo

Two-photon imaging, coupled to laser nanodissection, are useful tools to study degenerative and regenerative processes in the central nervous system with subcellular resolution. This protocol shows how to label, image, and dissect single climbing fibers in the cerebellar cortex in vivo.

Laser-Nanochirurgie der Kleinhirn-Axone<em&gt; In Vivo</em

Only a few neuronal populations in the central nervous system (CNS) of adult mammals show local regrowth upon dissection of their axon. In order to ...

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing.

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

Optogenetics has become a powerful tool for use in behavioral neuroscience experiments. This protocol offers a step-by-step guide to the design and set-up of laser systems, and provides a full protocol for carrying out multiple and simultaneous in vivo optogenetic stimulations compatible with most rodent behavioral testing paradigms.

In vivo optogenetische Stimulation des Nager Central Nervous System

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution ...