Gli autori desiderano ringraziare Neurotar Ltd. per l&#39;assistenza tecnica, CIMO Fondazione e FGSN per il sostegno finanziario.

Procedure che coinvolgono soggetti animali sono stati approvati dal Consiglio Experiment Animal Nazionale, Finlandia. 1 Preparazione degli animali per Imaging <ol><li> Anestetizzare un mouse da intraperitional (IP) iniezione di ketamina (0,08 mg per peso corporeo) e xilazina (0,01 mg per peso corporeo). Controllare l&#39;anestesia con il pizzico punta posteriore reflex. </li><li> Immergere gli occhi dell&#39;animale in collirio (Viscotears) per proteggere gli occhi dalla disidratazione. </li><li> Posizionare il mouse su una piastra elettrica (Supertech) a 37 ° C per evitare l&#39;ipotermia. </li><li> Pulire il rilievo del piede designato per l&#39;imaging con il 70% di etanolo. </li><li> Aggiungere una goccia d&#39;acqua sulla pelle del rilievo del piede per l&#39;accoppiamento immersione tra pelle e vetro di copertura. </li><li> Mettere il materiale da imballaggio in plastica sotto la zampa posteriore che è posizionato sotto un anello di metallo con coperchio di classe. </li><li> Regolare lo spessore del materiale di confezionamento in plastica per appiattire la pelle. </li><li> Mettere una goccia d&#39;acqua sulle glas copertinas per l&#39;immersione tra il vetro di copertura e l&#39;obiettivo. </li></ol> 2. metallo fissatore Anello Preparazione <ol><li> Per la stabilizzazione della pelle utilizzare il fissatore metallo. Usiamo disegni e modelli comunitari protetti fissatore due ali con un anello di metallo (per gentile concessione di Neurotar Ltd, Finlandia). Riempire la siringa con supercolla, mettere la piccola goccia di colla attraverso l&#39;ago sull&#39;anello e diffondere delicatamente la colla per la copertura uniforme della superficie dell&#39;anello. E &#39;fondamentale per mettere la quantità minima di colla che è necessario solo per una copertura uniforme, causa eccessiva quantità di colla può ridurre il campo della vista e di ostacolare l&#39;imaging successiva. NOTA: In alternativa, la combinazione di una barra metallica (da sotto) e dello standard vetrino da microscopio (come copertura) potrebbe essere utilizzato per appiattire la pelle e per garantire il corretto accoppiamento ottico del gruppo 14. Due clip di carta potrebbero essere utilizzati per fissare la zampa tra il vetro e la superficie barra di metallo (figura 4 </sTrong&gt;). </li><li> Coprire l&#39;anello con coperchio vetrino da microscopio (5 mm di diametro, Electron Microscopy Science). </li><li> Avvitare il fissatore anello alla barra metallica rigida che viene montaged sul palco microscopio motorizzato. </li></ol> 3. Imaging Procedura <ol><li> In caso di utilizzo Thy1-YFP-H mouse, scegliere la parte blu della fluorescenza spettri lampada per visualizzare fibre nervose. Trovare il nervo di interesse in modalità epifluorescenza e concentrarsi su di esso. </li><li> Annotare le coordinate di un punto per l&#39;imaging longitudinale. Utilizzare un pad carpale come punto di riferimento. Durante le seguenti sessioni di imaging, rilevare prima il pad carpale e poi trovare le stesse fibre nervose a monte grande e tornare indietro utilizzando le coordinate salvate. È essenziale posizionare il pad piede nella stessa direzione perpendicolare alla barra di metallo per mantenere lo stesso sistema di riferimento. </li><li> Attivare la modalità a due fotoni. Ai topi Thy1-YFP-H, è adatto per usare la lunghezza d&#39;onda di 950 nm di radiazione laservisualizzare le fibre nervose. </li><li> Selezionare la banda di laser e di emissione canali (450-480 nm per la seconda rilevazione armonica generazione, 520-550 nm per l&#39;imaging di nervi YFP-etichettati e 580-630 nm per la rilevazione di YFP fluorescenza e autofluorescenza dei capelli), iniziare con bassa potenza del laser (3-5%) per evitare fotodanneggiamento e candeggio. La tensione tipica sui tubi fotomoltiplicatori è 600-700 V per questo tipo di imaging. </li><li> Impostare la risoluzione desiderata (512 x 512 o 640 x 640 per misure eventi veloci, 800 x 800 o 1.024 x 1.024 per l&#39;imaging morfologico), passo assiale (1-3 micron), spessore del campione e gli intervalli di tempo (1-10 min). Il tempo di esposizione è dell&#39;ordine di 1 msec per un pixel. </li><li> Prima segnare i limiti superiori e inferiori del volume di imaging nel software. </li><li> Acquisire la pila di immagini di riferimento per il riferimento prima della lesione. Quando necessario, è possibile registrare il basale durante parecchi minuti. </li><li&gt; Ripetutamente (almeno ogni 10-15 minuti) controllare tasso di respirazione animale e riflessi, quando necessario applicare un importo aggiuntivo di anestetici. </li><li> Dopo l&#39;imaging pulito il pad con un fazzoletto e mettere il mouse in una scatola di ripresa a 36 ° C fino a quando non è completamente sveglio. NOTA: In genere, la durata di una sessione di imaging combinato con laser indotta lesione (vedi sotto) non superi 1 ora. Si consiglia di verificare che l&#39;animale è profondamente anestetizzato ogni 10-15 minuti; questo non dovrebbe interferire con l&#39;imaging in sé, ma deve essere considerato, mentre è prevista procedura sperimentale. La durata degli effetti di una singola dose di ketamina / xylazyne è di circa 30 e 40 minuti, quindi si consiglia di applicare ulteriore ¼ a ½ dose dopo 25-30 min. NOTA: Si deve essere considerata come bene quando la sperimentazione prevede che la frequenza delle sessioni di imaging per un singolo animale non deve superare 1 seduta per 2 giorni per evitare gli effetti negativi del recompetitivo anestesia. </li></ol> 4 Laser Lesion <ol><li> Dopo aver acquisito l&#39;immagine pila di riferimento, utilizzare il protocollo sbiancante per fare una micro lesione. </li><li> Aumentare la potenza del laser al 100%. </li><li> Aumentare il tempo di esposizione di 100-1.000 msec per regione di interesse (100-1,000x più che nel caso di immagini standard). </li><li> Delineare l&#39;area per la lesione. </li><li> Rendere la lesione accendendo lo sbiancamento. </li><li> Tornare alla modalità di imaging regolare e continuare con le registrazioni time-lapse. </li></ol> 5. Data Processing and Analysis <ol><li> Procedere con unmixing usando unmixing Spectral plug-in ImageJ 8 (Joachim Walter, <a href="http://rsbweb.nih.gov/ij/plugins/spectral-unmixing.html">http://rsbweb.nih.gov/ij/plugins/spectral-unmixing.html</a> ). </li><li> Aprire la serie di immagini e dividere i canali. </li><li> Trova l&#39;area libera dei nervi o dei capelli per le misurazioni del fondo. Mettere una regione of interesse in quella zona. </li><li> Delineare con cura la parte del capello, dove si distingue nettamente dai nervi. </li><li> Outline nervo nella parte dell&#39;immagine in cui è separato dai capelli. </li><li> Salva unmixing matrice. </li><li> Applicare matrice unmixing misurato per l&#39;intero stack. </li><li> Salvare le nuove pile di immagini elaborate in formato * tif. </li></ol>

<ol>
	<li>Lumpkin, E. A., Caterina, M. J. <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+sensory+transduction+in+the+skin.">Mechanisms of sensory transduction in the skin.</a> Nature. 445, 858-865 (2007).</li><li>Kennedy, W. R., Wendelschafer-Crabb, G., Johnson, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitation+of+epidermal+nerves+in+diabetic+neuropathy.">Quantitation of epidermal nerves in diabetic neuropathy.</a> Neurology. 47, 1042-1048 (1996).</li><li>Wu, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morton's+interdigital+neuroma:+a+clinical+review+of+its+etiology,+treatment,+and+results.">Morton's interdigital neuroma: a clinical review of its etiology, treatment, and results.</a> J. Foot Ankle Surg. 35, 112-119 (1996).</li><li>Lauria, G., Lombardi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skin+biopsy:+a+new+tool+for+diagnosing+peripheral+neuropathy.">Skin biopsy: a new tool for diagnosing peripheral neuropathy.</a> BMJ. 334, 1159-1162 (2007).</li><li>Cheng, C., Guo, G. F., Martinez, J. A., Singh, V., Zochodne, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+plasticity+of+axons+within+a+cutaneous+milieu.">Dynamic plasticity of axons within a cutaneous milieu.</a> J. Neurosci. 30, 14735-14744 (2010).</li><li>Wang, B., Zinselmeyer, B. H., McDole, J. R., Gieselman, P. A., Miller, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+Imaging+of+Leukocyte+Homing+and+Migration+in+vivo.">Non-invasive Imaging of Leukocyte Homing and Migration in vivo.</a> J Vis Exp. (46), e2062 (2010).</li><li>Sacconi, L., O'Connor, R. P., Jasaitis, A., Masi, A., Buffelli, M., Pavone, F. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+multiphoton+nanosurgery+of+cortical+neurons.">In vivo multiphoton nanosurgery of cortical neurons.</a> J Biomed Opt. 12, 050502 (2007).</li><li>Robinson, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traumatic+injury+to+peripheral+nerves.">Traumatic injury to peripheral nerves.</a> Muscle Nerve. 23, 863-873 (2000).</li><li>Feng, G., Mellor, R. H., Bernstein, M., Keller-Peck, C., Nguyen, Q. T., Wallace, M., Nerbonne, J. M., Lichtman, J. W., Sanes, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+neuronal+subsets+in+transgenic+mice+expressing+multiple+spectral+variants+of+GFP.">Imaging neuronal subsets in transgenic mice expressing multiple spectral variants of GFP.</a> Neuron. 28, 41-51 (2000).</li><li>Marinkovic, P., Reuter, M. S., Brill, M. S., Godinho, L., Kerschensteiner, M., Misgeld, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axonal+transport+deficits+and+degeneration+can+evolve+independently+in+mouse+models+of+amyotrophic+lateral+sclerosis.">Axonal transport deficits and degeneration can evolve independently in mouse models of amyotrophic lateral sclerosis.</a> Proc Natl Acad Sci U.S.A. 109, 4296-4301 (2012).</li><li>Amit, S., Yaron, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+systems+for+in+vivo+monitoring+and+microenvironmental+investigations+of+diabetic+neuropathy+in+a+murine+model.">Novel systems for in vivo monitoring and microenvironmental investigations of diabetic neuropathy in a murine model.</a> J Neural Transm. 119, 1317-1325 (2012).</li><li>Yu, H., Fischer, G., Jia, G., Reiser, J., Park, F., Hogan, Q. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lentiviral+gene+transfer+into+the+dorsal+root+ganglion+of+adult+rats.">Lentiviral gene transfer into the dorsal root ganglion of adult rats.</a> Mol Pain. 7, 63 (2011).</li><li>Yuryev, M., Khiroug, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+longitudinal+investigation+of+individual+nerve+endings+in+the+skin+of+anesthetized+mice+using+in+vivo+two-photon+microscopy.">Dynamic longitudinal investigation of individual nerve endings in the skin of anesthetized mice using in vivo two-photon microscopy.</a> J Biomed Opt. 17, 046007 (2012).</li></ol>

Gli autori dichiarano di non avere interessi finanziari in competizione.

In questo protocollo video dimostriamo il metodo per non invasiva longitudinale a due fotoni di imaging di terminazioni nervose singoli. La dinamica delle innervazioni pelle è influenzata in tali malattie come la psoriasi e la neuropatia periferica 2, e in lesioni traumatiche 9. L&#39;imaging a due fotoni permette un&#39;analisi dettagliata delle strutture fibre nervose in matrice di collagene. L&#39;uso di topi transgenici transgenici permette di evitare i problemi di...

A correction was made to <a href="/video/51045">In Vivo Two-Photon Microscopy of Single Nerve Endings in Skin</a>.
Leonard Khiroug was removed as an author.

Erratum: In Vivo Two-Photon Microscopy of Single Nerve Endings in Skin

Terminazioni nervose cutanee subiscono cambiamenti dinamici sotto diversi stati fisiopatologici. Le fibre nervose possono passare attraverso il processo di degenerazione e di rigenerazione o di ristrutturazione nel corso di tali malattie come neuropatia periferica 2 o Morton neuroma 3. Dopo la lesione traumatica, una parte importante di terminazioni nervose dinamiche in pelle è reinnervazione della zona danneggiata. Tuttavia, l&#39;approccio comune per le indagini di terminazioni nervose sia ex vivo istologica di sezionamento che non dispone di informazioni in tempo reale sui processi in corso 4. Utilizzo di marcatori fluorescenti geneticamente codificati, è possibile tracciare le terminazioni nervose nella pelle degli animali vivi, ottenendo così ricco di informazioni e significativamente più rilevante sui cambiamenti strutturali. L&#39;indagine di terminazioni nervose cutanee è possibile utilizzando la microscopia a fluorescenza convenzionale, tuttavia, la forte dispersione della luce del tessuto cutaneo mina fortemente la qualitàdei dati acquisiti 5. Microscopia Multiphoton permette l&#39;acquisizione di immagini ad alta risoluzione nei tessuti fortemente dispersione dovuta alla sommatoria non lineare di energia di eccitazione fotoni di luce con conseguente emissione di fluorescenza solo dal punto focale dell&#39;obiettivo. Questo effetto porta ad un forte aumento della profondità di penetrazione e il miglioramento di rapporto segnale-rumore per la misura nei tessuti cutanei 6. Utilizzando lo stesso laser per l&#39;imaging, è possibile produrre dissezione selettiva delle fibre nervose 7. Nel seguente protocollo mostriamo il metodo dell&#39;imaging longitudinale di terminazioni nervose cutanee in vivo in topi transgenici giornalista combinato con lesione selettiva laser con sistema disponibile in commercio microscopio multiphoton.

<table border="0" cellpadding="0" cellspacing="0" width="1231">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Round cover glass&#160;</td>
			<td style="width:209px;">Electron Microscopy Science</td>
			<td style="width:119px;">72296-05</td>
			<td style="width:687px;">5 mm diameter #1.5 thickness</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Eye drops Viscotears</td>
			<td style="width:209px;">Novartis</td>
			<td style="width:119px;"></td>
			<td>2mg/g</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Superglue Loctite 401</td>
			<td style="width:209px;">Henkel</td>
			<td>135429</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ketaminol</td>
			<td style="width:209px;">Intervet</td>
			<td style="width:119px;"></td>
			<td>Ketamine 50 mg/ml, working solution 10 mg/ml (use it 80 &#181;g per gramm of animal weight)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rompun</td>
			<td style="width:209px;">Bayer Healthcare</td>
			<td style="width:119px;"></td>
			<td>Xylazine 20 mg/ml, working solution 1.25 mg/ml (use it 10 &#181;g per gramm of animal weight)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:209px;"></td>
			<td style="width:119px;"></td>
			<td style="width:687px;">Working solution is a mixture of Ketamine 10 mg/ml and Xylazine 1.25 mg/ml in PBS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ethanol 70%</td>
			<td style="width:209px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Distilled water or Milli-Q water</td>
			<td style="width:209px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Syringes 1ml&#160;</td>
			<td style="width:209px;">BD</td>
			<td style="width:119px;">300013</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">30G 1/2&#34; needles</td>
			<td style="width:209px;">BD</td>
			<td style="width:119px;">304000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Plastic packaging material</td>
			<td style="width:209px;"></td>
			<td style="width:119px;"></td>
			<td>Could be purchaized from general hardware store</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">FV-1000MPE microscope</td>
			<td style="width:209px;">Olympus</td>
			<td style="width:119px;">FV-1000MPE</td>
			<td>Microscope with motorized stage and rigid metal bar for fixation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">25X XLPlan objective</td>
			<td style="width:209px;">Olympus</td>
			<td style="width:119px;">XLPLN 25XWMP</td>
			<td>Water imersion objective optimized for multiphoton imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mai-Tai DeepSee laser (2W)</td>
			<td style="width:209px;">SpectraPhysics</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Heating pad</td>
			<td style="width:209px;">Supertech</td>
			<td style="width:119px;">TMP-5b</td>
			<td>Heating pad with a temperature controller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Metal ring fixator</td>
			<td style="width:209px;">Neurotar Ltd.</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ImageJ</td>
			<td style="width:209px;">NIH</td>
			<td style="width:119px;"></td>
			<td>Open source software for image processing and analysis, http://rsbweb.nih.gov/ij/&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Thy1-YFPH mice strain</td>
			<td style="width:209px;">JaxLab</td>
			<td style="width:119px;">003782</td>
			<td></td>
		</tr>
	</tbody>
</table>

in vivo two-photon microscopy of single nerve endings in skin

Terminazioni nervose in pelle sono coinvolti in processi fisiologici quali sensing 1 e nei processi patologici come il dolore neuropatico 2. Il loro posizionamento close-superficie facilita l&#39;imaging microscopico delle terminazioni nervose della pelle nel vivere intatta di un animale. Utilizzando la microscopia multiphoton, è possibile ottenere immagini belle superando il problema della forte dispersione della luce del tessuto cutaneo. Reporter topi transgenici che esprimono EYFP sotto il controllo di Thy-1 promoter nei neuroni (compresi periferia neuroni sensoriali) sono adatti per gli studi longitudinali delle singole terminazioni nervose più lunghi periodi di tempo fino a diversi mesi o addirittura per tutta la vita. Inoltre, utilizzando lo stesso laser a femtosecondi come per imaging, è possibile produrre lesioni altamente selettivi di fibre nervose per gli studi della ristrutturazione fibre nervose. Qui, vi presentiamo un protocollo semplice e affidabile per multiphoton longitudinale imaging in vivo emicrochirurgia laser-based sul topo terminazioni nervose della pelle.

Utilizzando la tecnica descritta è possibile seguire la stessa fibra dopo la lesione e per studiare la degradazione delle terminazioni nervose danneggiate (Figura 1). Acquisizione della pila con spessore di 120-150 micron è generalmente appropriato per imaging ripetitivo durante parecchi giorni, al fine di mantenere l&#39;intera fibra nel campo visivo. La lesione tipicamente può essere prodotto sinteticamente quando il materiale di imballaggio in plastica viene regolata p...

Watch this Scientific Journal Video about In Vivo Two-Photon Microscopy of Single Nerve Endings in Skin at JoVE.com

In Vivo Two-Photon Microscopy of Single Nerve Endings in Skin

Il protocollo per l&#39;imaging longitudinale dinamico e selettivo lesione laser di terminazioni nervose in topi transgenici giornalista è presentato.

In Vivo microscopia a due fotoni di Endings singolo nervo in pelle

Nerve endings in skin are involved in physiological processes such as sensing1 as well as in pathological processes such as neuropathic pain2. Their ...

in-vivo-two-photon-microscopy-of-single-nerve-endings-in-skin

Research

JoVE Journal

Neuroscience

In Vivo Two-Photon Microscopy of Single Nerve Endings in Skin

10.7K Views.  University of Helsinki.  Il protocollo per l'imaging longitudinale dinamico e selettivo lesione laser di terminazioni nervose in topi transgenici giornalista è presentato. 

Video: In Vivo Two-Photon Microscopy of Single Nerve Endings in Skin

In vivo Imaging of the Mouse Spinal Cord Using Two-photon Microscopy

In vivo imaging using two-photon microscopy 1 in mice that have been genetically engineered to express fluorescent proteins in specific cell types 2-3 has significantly broadened our knowledge of physiological and pathological processes in numerous tissues in vivo 4-7. In studies of the central nervous system (CNS), there has been a broad application of in vivo imaging in the brain, which has produced a plethora of novel and often unexpected findings about the behavior of cells such as neurons, astrocytes, microglia, under physiological or pathological conditions 8-17. However, mostly technical complications have limited the implementation of in vivo imaging in studies of the living mouse spinal cord. In particular, the anatomical proximity of the spinal cord to the lungs and heart generates significant movement artifact that makes imaging the living spinal cord a challenging task.
We developed a novel method that overcomes the inherent limitations of spinal cord imaging by stabilizing the spinal column, reducing respiratory-induced movements and thereby facilitating the use of two-photon microscopy to image the mouse spinal cord in vivo. This is achieved by combining a customized spinal stabilization device with a method of deep anesthesia, resulting in a significant reduction of respiratory-induced movements. This video protocol shows how to expose a small area of the living spinal cord that can be maintained under stable physiological conditions over extended periods of time by keeping tissue injury and bleeding to a minimum. Representative raw images acquired in vivo detail in high resolution the close relationship between microglia and the vasculature. A timelapse sequence shows the dynamic behavior of microglial processes in the living mouse spinal cord. Moreover, a continuous scan of the same z-frame demonstrates the outstanding stability that this method can achieve to generate stacks of images and/or timelapse movies that do not require image alignment post-acquisition. Finally, we show how this method can be used to revisit and reimage the same area of the spinal cord at later timepoints, allowing for longitudinal studies of ongoing physiological or pathological processes in vivo.

In vivo Imaging of the Mouse Spinal Cord Using Two-photon Microscopy

A minimally invasive protocol to stabilize the mouse spinal column and perform repetitive in vivo spinal cord imaging using two-photon microscopy is described. This method combines a spinal stabilization device and an anesthetic regimen to minimize respiratory-induced movements and produce raw imaging data that require no alignment or other post-processing.

Imaging in vivo del midollo spinale di topo Utilizzo di due fotoni Microscopia

In vivo imaging using two-photon microscopy 1 in mice that have been genetically engineered to express fluorescent proteins in specific cell types 2-3 has ...

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Neuroscienze

Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains technically challenging. One approach, Activation-Induced Manganese-enhanced MRI (AIM MRI), has been used successfully to map neuronal activity in rodents 1-5. In AIM MRI, Mn2+ acts a calcium analog and accumulates in depolarized neurons 6,7. Because Mn2+ shortens the T1 tissue property, regions of elevated neuronal activity will enhance in MRI. Furthermore, Mn2+ clears slowly from the activated regions; therefore, stimulation can be performed outside the magnet prior to imaging, enabling greater experimental flexibility. However, because Mn2+ does not readily cross the blood-brain barrier (BBB), the need to open the BBB has limited the use of AIM MRI, especially in mice.
One tool for opening the BBB is ultrasound. Though potentially damaging, if ultrasound is administered in combination with gas-filled microbubbles (i.e., ultrasound contrast agents), the acoustic pressure required for BBB opening is considerably lower. This combination of ultrasound and microbubbles can be used to reliably open the BBB without causing tissue damage 8-11.
Here, a method is presented for performing AIM MRI by using microbubbles and ultrasound to open the BBB. After an intravenous injection of perflutren microbubbles, an unfocused pulsed ultrasound beam is applied to the shaved mouse head for 3 minutes. For simplicity, we refer to this technique of BBB Opening with Microbubbles and UltraSound as BOMUS 12. Using BOMUS to open the BBB throughout both cerebral hemispheres, manganese is administered to the whole mouse brain. After experimental stimulation of the lightly sedated mice, AIM MRI is used to map the neuronal response.
To demonstrate this approach, herein BOMUS and AIM MRI are used to map unilateral mechanical stimulation of the vibrissae in lightly sedated mice 13. Because BOMUS can open the BBB throughout both hemispheres, the unstimulated side of the brain is used to control for nonspecific background stimulation. The resultant 3D activation map agrees well with published representations of the vibrissae regions of the barrel field cortex 14. The ultrasonic opening of the BBB is fast, noninvasive, and reversible; and thus this approach is suitable for high-throughput and/or longitudinal studies in awake mice.

A technique is described for broadly opening the blood-brain barrier in the mouse using microbubbles and ultrasound. Using this technique, manganese can be administered to the mouse brain. Because manganese is an MRI contrast agent that accumulates in depolarized neurons, this approach enables imaging of neuronal activity.

Neuroimaging funzionale con l&#39;impiego dell&#39;ecografia emato-encefalica e la barriera di Turbativa del Manganese-enhanced MRI

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains ...

In Vivo Two-photon Imaging Of Experience-dependent Molecular Changes In Cortical Neurons

The brain's ability to change in response to experience is essential for healthy brain function, and abnormalities in this process contribute to a variety of brain disorders1,2. To better understand the mechanisms by which brain circuits react to an animal's experience requires the ability to monitor the experience-dependent molecular changes in a given set of neurons, over a prolonged period of time, in the live animal. While experience and associated neural activity is known to trigger gene expression changes in neurons1,2, most of the methods to detect such changes do not allow repeated observation of the same neurons over multiple days or do not have sufficient resolution to observe individual neurons3,4. Here, we describe a method that combines in vivo two-photon microscopy with a genetically encoded fluorescent reporter to track experience-dependent gene expression changes in individual cortical neurons over the course of day-to-day experience. 
One of the well-established experience-dependent genes is Activity-regulated cytoskeletal associated protein (Arc)5,6. The transcription of Arc is rapidly and highly induced by intensified neuronal activity3, and its protein product regulates the endocytosis of glutamate receptors and long-term synaptic plasticity7. The expression of Arc has been widely used as a molecular marker to map neuronal circuits involved in specific behaviors3. In most of those studies, Arc expression was detected by in situ hybridization or immunohistochemistry in fixed brain sections. Although those methods revealed that the expression of Arc was localized to a subset of excitatory neurons after behavioral experience, how the cellular patterns of Arc expression might change with multiple episodes of repeated or distinctive experiences over days was not investigated. 
In vivo two-photon microscopy offers a powerful way to examine experience-dependent cellular changes in the living brain8,9. To enable the examination of Arc expression in live neurons by two-photon microscopy, we previously generated a knock-in mouse line in which a GFP reporter is placed under the control of the endogenous Arc promoter10. This protocol describes the surgical preparations and imaging procedures for tracking experience-dependent Arc-GFP expression patterns in neuronal ensembles in the live animal. In this method, chronic cranial windows were first implanted in Arc-GFP mice over the cortical regions of interest. Those animals were then repeatedly imaged by two-photon microscopy after desired behavioral paradigms over the course of several days. This method may be generally applicable to animals carrying other fluorescent reporters of experience-dependent molecular changes4.

In Vivo Two-photon Imaging Of Experience-dependent Molecular Changes In Cortical Neurons

Experience-dependent molecular changes in neurons are essential for the brain's ability to adapt in response to behavioral challenges. An in vivo two-photon imaging method is described here that allows the tracking of such molecular changes in individual cortical neurons through genetically encoded reporters.

In Vivo a due fotoni di imaging dei cambi molecolari esperienza-dipendenti nei neuroni corticali

The brain's ability to change in response to experience is essential for healthy brain function, and abnormalities in this process contribute to a variety ...

Simultaneous Two-photon In Vivo Imaging of Synaptic Inputs and Postsynaptic Targets in the Mouse Retrosplenial Cortex

This video shows the craniotomy procedure that allows chronic imaging of neurons in the mouse retrosplenial cortex (RSC) using in vivo two-photon microscopy in Thy1-GFP transgenic mouse line. This approach creates a possibility to investigate the correlation of behavioural manipulations with changes in neuronal morphology in vivo.
The cranial window implantation procedure was considered to be limited only to the easily accessible cortex regions such as the barrel field. Our approach allows visualization of neurons in the highly vascularized RSC. RSC is an important element of the brain circuit responsible for spatial memory, previously deemed to be problematic for in vivo two-photon imaging.
The cranial window implantation over the RSC is combined with an injection of mCherry-expressing recombinant adeno-associated virus (rAAVmCherry) into the dorsal hippocampus. The expressed mCherry spreads out to axonal projections from the hippocampus to RSC, enabling the visualization of changes in both presynaptic axonal boutons and postsynaptic dendritic spines in the cortex. 
This technique allows long-term monitoring of experience-dependent structural plasticity in RSC.

Simultaneous Two-photon In Vivo Imaging of Synaptic Inputs and Postsynaptic Targets in the Mouse Retrosplenial Cortex

This video shows the craniotomy procedure that allows chronic imaging of neurons in mouse retrosplenial cortex using in vivo two photon microscopy in Thy1-GFP transgenic line. This approach is combined with injection of mCherry-expressing adeno-associated virus into dorsal hippocampus. These techniques allow long-term monitoring of experience-dependent structural plasticity in RSC.

Simultanea a due fotoni<em&gt; In Vivo</em&gt; Imaging di Synaptic ingressi e degli obiettivi postsinaptici nella corteccia mouse retrosplenial

This video shows the craniotomy procedure that allows chronic imaging of neurons in the mouse retrosplenial cortex (RSC) using in vivo two-photon ...

Quantification of Cerebral Vascular Architecture using Two-photon Microscopy in a Mouse Model of HIV-induced Neuroinflammation

Human Immunodeficiency Virus 1 (HIV-1) infection frequently results in HIV-1 Associated Neurocognitive Disorders (HAND), and is characterized by a chronic neuroinflammatory state within the central nervous system (CNS), thought to be driven principally by virally-mediated activation of microglia and brain resident macrophages. HIV-1 infection is also accompanied by changes in cerebrovascular blood flow (CBF), raising the possibility that HIV-associated chronic neuroinflammation may lead to changes in CBF and/or in cerebral vascular architecture. To address this question, we have used a mouse model for HIV-induced neuroinflammation, and we have tested whether long-term exposure to this inflammatory environment may damage brain vasculature and result in rarefaction of capillary networks. In this paper we describe a method to quantify changes in cortical capillary density in a mouse model of neuroinflammatory disease (HIV-1 Tat transgenic mice). This generalizable approach employs in vivo two-photon imaging of cortical capillaries through a thin-skull cortical window, as well as ex vivo two-photon imaging of cortical capillaries in mouse brain sections. These procedures produce images and z-stack files of capillary networks, respectively, which can be then subjected to quantitative analysis in order to assess changes in cerebral vascular architecture.

This paper describes a method by which the vascular architecture in the brain can be quantified using in vivo and ex vivo two-photon microscopy.

Quantificazione dei cerebrale vascolare Architettura con due fotoni Microscopia in un modello murino di Neuroinflammation HIV-indotta

Human Immunodeficiency Virus 1 (HIV-1) infection frequently results in HIV-1 Associated Neurocognitive Disorders (HAND), and is characterized by a chronic ...

Optical Monitoring of Living Nerve Terminal Labeling in Hair Follicle Lanceolate Endings of the Ex Vivo Mouse Ear Skin

A novel dissection and recording technique is described for optical monitoring staining and de-staining of lanceolate terminals surrounding hair follicles in the skin of the mouse pinna. The preparation is simple and relatively fast, reliably yielding extensive regions of multiple labeled units of living nerve terminals to study uptake and release of styryl pyridinium dyes extensively used in studies of vesicle recycling. Subdividing the preparations before labeling allows test vs. control comparisons in the same ear from a single individual. Helpful tips are given for improving the quality of the preparation, the labeling and the imaging parameters. This new system is suitable for assaying pharmacologically and mechanically-induced uptake and release of these vital dyes in lanceolate terminals in both wild-type and genetically modified animals. Examples of modulatory influences on labeling intensity are given.

Optical Monitoring of Living Nerve Terminal Labeling in Hair Follicle Lanceolate Endings of the Ex Vivo Mouse Ear Skin

Here we describe a novel preparation for imaging live lanceolate sensory terminals of palisade endings that innervate mouse ear skin hair follicles during staining and destaining with styryl pyridinium dyes.

Il monitoraggio ottico di Living nervo terminale Etichettatura nel follicolo pilifero lanceolate Endings del<em&gt; Ex Vivo</em&gt; Mouse Ear pelle

A novel dissection and recording technique is described for optical monitoring staining and de-staining of lanceolate terminals surrounding hair follicles ...

Two-photon Calcium Imaging in Neuronal Dendrites in Brain Slices

Calcium (Ca2+) imaging is a powerful tool to investigate the spatiotemporal dynamics of intracellular Ca2+ signals in neuronal dendrites. Ca2+ fluctuations can occur through a variety of membrane and intracellular mechanisms and play a crucial role in the induction of synaptic plasticity and regulation of dendritic excitability. Hence, the ability to record different types of Ca2+ signals in dendritic branches is valuable for groups studying how dendrites integrate information. The advent of two-photon microscopy has made such studies significantly easier by solving the problems inherent to imaging in live tissue, such as light scattering and photodamage. Moreover, through combination of conventional electrophysiological techniques with two-photon Ca2+ imaging, it is possible to investigate local Ca2+ fluctuations in neuronal dendrites in parallel with recordings of synaptic activity in soma. Here, we describe how to use this method to study the dynamics of local Ca2+ transients (CaTs) in dendrites of GABAergic inhibitory interneurons. The method can be also applied to studying dendritic Ca2+ signaling in different neuronal types in acute brain slices.

We present a method combining whole-cell patch-clamp recordings and two-photon imaging to record Ca2+ transients in neuronal dendrites in acute brain slices.

Imaging del due-fotone calcio nei dendriti neuronali nelle fette del cervello

Calcium (Ca2+) imaging is a powerful tool to investigate the spatiotemporal dynamics of intracellular Ca2+ signals in neuronal dendrites. Ca2+ ...

In Vivo Two-photon Imaging of Cortical Neurons in Neonatal Mice

Two-photon imaging is a powerful tool for the in vivo analysis of neuronal circuits in the mammalian brain. However, a limited number of in vivo imaging methods exist for examining the brain tissue of live newborn mammals. Herein we summarize a protocol for imaging individual cortical neurons in living neonatal mice. This protocol includes the following two methodologies: (1) the Supernova system for sparse and bright labeling of cortical neurons in the developing brain, and (2) a surgical procedure for the fragile neonatal skull. This protocol allows the observation of temporal changes of individual cortical neurites during neonatal stages with a high signal-to-noise ratio. Labeled cell-specific gene silencing and knockout can also be achieved by combining the Supernova with RNA interference and CRISPR/Cas9 gene editing systems. This protocol can, thus, be used for analyzing the developmental dynamics of cortical neurons, molecular mechanisms that control the neuronal dynamics, and changes in neuronal dynamics in disease models.

In Vivo Two-photon Imaging of Cortical Neurons in Neonatal Mice

We present an in vivo two-photon imaging protocol for imaging the cerebral cortex of neonatal mice. This method is suitable for analyzing the developmental dynamics of cortical neurons, the molecular mechanisms that control the neuronal dynamics, and the changes in neuronal dynamics in disease models.

In Vivo Due-fotone Imaging dei neuroni corticali in topi neonatali

Two-photon imaging is a powerful tool for the in vivo analysis of neuronal circuits in the mammalian brain. However, a limited number of in vivo imaging ...

In Vivo Three-Dimensional Two-Photon Microscopy to Study Conducted Vascular Responses by Local ATP Ejection Using a Glass Micro-Pipette

Maintenance of normal brain function requires a sufficient and efficient supply of oxygen and nutrition by a complex network of vessels. However, the regulation of cerebral blood flow (CBF) is incompletely understood, especially at the capillary level. Two-photon microscopy is a powerful tool widely used to study CBF and its regulation. Currently, this field is limited by the lack of in vivo two-photon microscopy studies examining (1) CBF responses in three-dimensions, (2) conducted vascular responses, and (3) localized interventions within the vascular network. Here, we describe a 3D in vivo method using two-photon microscopy to study conducted vascular responses elicited by&#160;local ejection of ATP with a glass micro-pipette. Our method uses fast and repetitive hyperstack two-photon imaging providing precise diameter measurements by maximal intensity projection of the obtained images. Furthermore, we show that this method can also be used to study 3D astrocytic calcium responses. We also discuss the advantages and limitations of glass micro-pipette insertion and two-photon hyperstack imaging.

We present an optimized local ejection procedure using a glass micro-pipette and a fast two-photon hyperstack imaging method, which allows precise measurement of capillary diameter changes and investigation of its regulation in three dimensions.

In Vivo microscopia bidimensionale bidimensionale per studiare le risposte vascolari mediante l'espulsione locale dell'ATP utilizzando una micropipetta di vetro

Maintenance of normal brain function requires a sufficient and efficient supply of oxygen and nutrition by a complex network of vessels. However, the ...

Visualizing Protein Kinase A Activity In Head-fixed Behaving Mice Using In Vivo Two-photon Fluorescence Lifetime Imaging Microscopy

Neuromodulation exerts powerful control over brain function. Dysfunction of neuromodulatory systems results in neurological and psychiatric disorders. Despite their importance, technologies for tracking neuromodulatory events with cellular resolution are just beginning to emerge. Neuromodulators, such as dopamine, norepinephrine, acetylcholine, and serotonin, trigger intracellular signaling events via their respective G protein-coupled receptors to modulate neuronal excitability, synaptic communications, and other neuronal functions, thereby regulating information processing in the neuronal network. The above mentioned neuromodulators converge onto the cAMP/protein kinase A (PKA) pathway. Therefore, in vivo PKA imaging with single-cell resolution was developed as a readout for neuromodulatory events in a manner analogous to calcium imaging for neuronal electrical activities. Herein, a method is presented to visualize PKA activity at the level of individual neurons in the cortex of head-fixed behaving mice. To do so, an improved A-kinase activity reporter (AKAR), called tAKAR&#945;, is used, which is based on F&#246;rster resonance energy transfer (FRET). This genetically-encoded PKA sensor is introduced into the motor cortex via in utero electroporation (IUE) of DNA plasmids, or stereotaxic injection of adeno-associated virus (AAV). FRET changes are imaged using two-photon fluorescence lifetime imaging microscopy (2pFLIM), which offers advantages over ratiometric FRET measurements for quantifying FRET signal in light-scattering brain tissue. To study PKA activities during enforced locomotion, tAKAR&#945; is imaged through a chronic cranial window above the cortex of awake, head-fixed mice, which run or rest on a speed-controlled motorized treadmill. This imaging approach will be applicable to many other brain regions to study corresponding behavior-induced PKA activities and to other FLIM-based sensors for in vivo imaging.

A procedure is presented to visualize protein kinase A activities in head-fixed, behaving mice. An improved A-kinase activity reporter, tAKAR&#945;, is expressed in cortical neurons and made accessible for imaging through a cranial window. Two-photon fluorescence lifetime imaging microscopy is used to visualize PKA activities in vivo during enforced locomotion.

Visualizzazione della proteina Kinase un'attività nel mouse behaving fissato per la testa utilizzando la microscopia fluorescenza a due fotoinina in vivo

Neuromodulation exerts powerful control over brain function. Dysfunction of neuromodulatory systems results in neurological and psychiatric disorders. ...

Methods Article

In Vivo microscopia a due fotoni di Endings singolo nervo in pelle