We thank Valentina Greco for the K14-mCherry-H2B mice. We are grateful to the Emory University Physics Department Machine Shop for generating the glass coverslip disks. This work was funded by Career Development Award #IK2 BX005370 from the US Department of Veterans Affairs BLRD Service to LS, NIH Awards RF1-AG079269 and R56-AG072473 to MJMR, and I3 Emory SOM/GT Computational and Data Analysis Award to MJMR.

This research was performed in compliance with Emory University and Atlanta Veterans Affairs Medical Center animal care and use guidelines and has been approved by the Institutional Animal Care and Use Committee (IACUC).
1. Installing the live imaging insert on the inverted microscope stage
<ol>
	<li>Construct the insert using .stl files (Supplementary File 1, Supplementary File 2, and Supplementary File 3)&#160;specifying the 3D dimensions and design (see Figure 1 and Figure 2A), a 3D printer, and polylactic acid (PLA).</li>
	<li>Carefully place the insert (Figure 2B,C) into the large microscope stage groove (Figure 2C and&#160;Figure 3A). Use screws to secure the insert via four screw holes located in each corner of the insert (Figure 2B-C). 
	NOTE: The insert is bidirectional and can be rotated 180&#176; depending on the orientation of the microscope&#160;stage, and anesthesia apparatus.</li>
	<li>Slide the heat plate into the insert plug side-down (Figure 2D)&#160;so the unit lays atop the lower insert grooves with the plug port passing underneath the stage (Figure 3B).</li>
	<li>Align the grooved circular opening in the insert with a 40x silicone oil immersion objective (Figure 3C) and apply silicone oil to the center of the objective.
	<ol>
		<li>If imaging over longer time periods (&#62;1 h), apply a generous dollop of oil that will persist at the coverslip/objective interface throughout imaging. Do not allow oil to spill over the edges of the lens.</li>
	</ol>
	</li>
	<li>Use a syringe to apply a small quantity of vacuum grease along the grooved circular opening and lay the coverslip disk atop to seal onto the insert (Figure 3D). 
	NOTE: The coverslip disk is created by removing the walls of a 35 mm x 10 mm glass-bottom cell culture dish (performed by a machine shop).</li>
	<li>Raise the 40x objective until the oil kisses the bottom of the glass coverslip.</li>
</ol>
2. Isoflurane configuration and mouse prep
<ol>
	<li>Position the low-flow electronic vaporizer components (anesthesia chamber, tubing, vaporizer, charcoal canister) to allow the nose cone and attached tubing to reach the insert (Figure 3A). 
	CAUTION: Isoflurane is an inhalation anesthetic and should be handled with care to avoid spills and minimize human exposure.</li>
	<li>Measure the weight of the isoflurane bottle prior to use and log. Attach the cap from the electronic vaporizer to the isoflurane bottle.</li>
	<li>Connect the power cord to the electronic vaporizer. Close the blue nose cone clips and open the white induction chamber clips to allow airflow through the chamber into the charcoal canister. Remove the red ambient air cap from the left side of the machine to allow air flow.</li>
	<li>Allow the system to warm up for 5 min at 200 mL/min (low flow) and 2% isoflurane. 
	NOTE: Although the nose cone setting is selected, the blue nose cone line should remain closed, and the white induction chamber line should remain open.</li>
	<li>Once the system is properly equilibrated, purge the lines to remove remaining isoflurane from the chamber.</li>
	<li>Place the mouse in the induction chamber and select High Flow. Complete all mouse preparation (i.e., hair removal, topical drug delivery, eye ointment application, etc.) prior to laying the animal&#39;s body atop the insert. Confirm the mouse is fully anesthetized using the toe pinch reflex method.
	<ol>
		<li>With the leg extended, use a fingernail to firmly pinch the toe without causing physical damage. If the mouse exhibits a positive reaction to the stimulus (i.e., leg retraction, foot twitch, etc.), continue administering anesthetic within the chamber until no reaction is observed. Once appropriately anesthetized, the mouse breathing rate&#160;should slow to ~55-65 breaths per minute18.</li>
	</ol>
	</li>
	<li>When the mouse is fully anesthetized, select High Flow again to stop isoflurane delivery. Purge the chamber before opening and adjust the clips (blue: open; white: closed) to deliver isoflurane through the nose cone. Select Low Flow while the nose cone is attached to the mouse to continue isoflurane delivery.</li>
	<li>Thread isoflurane tubing with the attached nose cone through the corner tubing bracket on the insert (Figure 3A and Figure 5).</li>
</ol>
3. Mouse placement on the insert for intravital imaging
<ol>
	<li>Plug the heat plate into the controller (containing an attached anal probe), power on, and allow the plate to reach 36 &#176;C (Figure 4A).</li>
	<li>Remove the anesthetized mouse from the induction chamber and lay across the heat plate (Figure 4B and Figure 5A). Perform the transfer from chamber to insert rapidly to minimize the time the mouse is active without inhalant anesthesia.</li>
	<li>Secure the nose cone onto the mouse (Figure 4B,C, and Figure 5). If necessary, use tape to further secure the angle and positioning of the nose cone.</li>
	<li>Insert the anal probe and adjust the controller temperature until the mouse body temperature is stable at ~36 &#176;C (Figure 4A,B). After the mouse is properly positioned, use plastic cling wrap to trap heat, if needed, to further support the appropriate body temperature (Figure 4C).</li>
	<li>Position the mouse so the head aligns with the coverslip disk and immobilize the ear onto the center of the glass coverslip using a metal ear clip (Figure 5A,B) or tape (Figure 5C). 
	NOTE: The pressure of the metal ear clip on the ear can be adjusted by loosening the screw that secures the clip to the insert. A metal spring can be added for increased clip tightening flexibility.
	<ol>
		<li>To change the ear clip location, unscrew the bolt with a 2.5 mm Allen wrench and transfer to the secondary site (Figure 2B,C). When reassembling the ear clip, place the clip against the insert, followed by the washer on top. Use a bolt to securely fasten the clip with slight force to pivot the clip.</li>
	</ol>
	</li>
	<li>Adjust the objective z-positioning until the cells are within the focal place (Figure 6A,D). Set the z-stack and time-lapse parameters according to the experimental goals and commence image acquisition. 
	NOTE: If the correct setup is achieved, the mouse ear can be imaged for at least 3 consecutive h (Figure 6A&#39;,D&#39;).
	<ol>
		<li>Once the z-stack boundaries are set, adjust the laser power and gain to ensure no z-plane is oversaturated to minimize photobleaching. Determine the time-lapse parameters using the total thickness of the z-stack, step numbers (Nyquist sampling recommended), and time intervals.</li>
		<li>Determine the imaging parameters (time intervals, total imaging time, etc.) using multiple factors, including animal viability under anesthesia, laser-induced photobleaching/phototoxicity, and the goal of live imaging (i.e., cell division dynamics, cell-cell interactions, etc.).</li>
	</ol>
	</li>
</ol>
4. Termination of imaging
<ol>
	<li>Turn on the water-circulating heat pad and set to Continuous Cycle and 35 &#176;C for at least 30 min prior to the termination of image acquisition.</li>
	<li>Upon imaging completion, select Low Flow on the electronic vaporizer to stop isoflurane delivery and move the mouse to a heat pad until ambulatory.</li>
	<li>Once awake, move the mouse back to the transfer container while continuing to maintain on a heat pad until fully ambulatory. Consistently monitor the mouse while on the heat pad until it is responsive.</li>
	<li>On the electronic vaporizer, click Select Menu &#62; Anesthetic Control &#62; Empty. Remove the isoflurane bottle from the system and place the manufacturer&#39;s cap back onto the bottle.</li>
	<li>Measure the weight of the isoflurane bottle and charcoal canister and enter weights into log. Once the charcoal canister weighs 50 g over baseline measurement, dispose of the canister and replace it with a new unit. Return the isoflurane to the lockbox.</li>
	<li>Remove the coverslip disk and wipe clean with lens paper and lens solution. Store properly to avoid scratches for reuse.</li>
	<li>Remove the anesthesia&#160;tubing from the insert bracket and unscrew the insert from the microscope stage.</li>
</ol>

Intravital Imaging Using an Inverted Microscope to Track Skin Cell Dynamics

<ol>
	<li>Babes, L., Yipp, B. G., Senger, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+microscopy+of+the+metastatic+pulmonary+environment.">Intravital microscopy of the metastatic pulmonary environment.</a> Methods in Molecular Biology. , 383-396 (2023).</li><li>Nal Chen, ., 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=Neutrophils+promote+glioblastoma+tumor+cell+migration+after+biopsy.">Neutrophils promote glioblastoma tumor cell migration after biopsy.</a> Cells. 11 (14), 2196 (2022).</li><li>Courson, J. A., Langlois, K. W., Lam, F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+microscopy+to+study+platelet-leukocyte-endothelial+interactions+in+the+mouse+liver.">Intravital microscopy to study platelet-leukocyte-endothelial interactions in the mouse liver.</a> Journal of Visualized Experiments. 188 (188), (2022).</li><li>Rios, A. C., van Rheenen, J., Scheele, C. L. G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multidimensional+imaging+of+breast+cancer.">Multidimensional imaging of breast cancer.</a> Cold Spring Harbor Perspectives in Medicine. 13 (5), (2022).</li><li>Fischer, M., Edelblum, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+microscopy+to+visualize+murine+small+intestinal+intraepithelial+lymphocyte+migration.">Intravital microscopy to visualize murine small intestinal intraepithelial lymphocyte migration.</a> Current Protocols. 2 (8), (2022).</li><li>Pineda, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+imaging+of+hair+follicle+regeneration+in+the+mouse.">Intravital imaging of hair follicle regeneration in the mouse.</a> Nature Protocols. 10 (7), 1116-1130 (2015).</li><li>Entenberg, D., Oktay, M. H., Condeelis, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+imaging+to+study+cancer+progression+and+metastasis.">Intravital imaging to study cancer progression and metastasis.</a> Nature Reviews. Cancer. 23 (1), 25-42 (2023).</li><li>Turk, M., Biernaskie, J., Mahoney, D. J., Jenne, C. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+microscopy+techniques+to+image+wound+healing+in+mouse+skin.">Intravital microscopy techniques to image wound healing in mouse skin.</a> Methods in Molecular Biology. , 165-180 (2022).</li><li>Pal Arndt, ., 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+quantitative+3D+intravital+look+at+the+juxtaglomerular+renin-cell-niche+reveals+an+individual+intra/extraglomerular+feedback+system.">A quantitative 3D intravital look at the juxtaglomerular renin-cell-niche reveals an individual intra/extraglomerular feedback system.</a> Frontiers in Physiology. 13, 980787 (2022).</li><li>Oal Yam, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neutrophil+conversion+to+a+tumor-killing+phenotype+underpins+effective+microbial+therapy.">Neutrophil conversion to a tumor-killing phenotype underpins effective microbial therapy.</a> Cancer Research. 83 (8), 1315-1328 (2023).</li><li>Huang, S., Rompolas, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-photon+microscopy+for+intracutaneous+imaging+of+stem+cell+activity+in+mice.">Two-photon microscopy for intracutaneous imaging of stem cell activity in mice.</a> Experimental Dermatology. 26 (5), 379-383 (2017).</li><li>Durr, N. J., Weisspfennig, C. T., Holfeld, B. A., Ben-Yakar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maximum+imaging+depth+of+two-photon+autofluorescence+microscopy+in+epithelial+tissues.">Maximum imaging depth of two-photon autofluorescence microscopy in epithelial tissues.</a> Journal of Biomedical Optics. 16 (2), 026008 (2011).</li><li>Tauer, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advantages+and+risks+of+multiphoton+microscopy+in+physiology.">Advantages and risks of multiphoton microscopy in physiology.</a> Experimental Physiology. 87 (6), 709-714 (2002).</li><li>Yoshitake, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+comparison+between+confocal+and+multiphoton+microscopy+for+rapid+histopathological+evaluation+of+unfixed+human+breast+tissue.">Direct comparison between confocal and multiphoton microscopy for rapid histopathological evaluation of unfixed human breast tissue.</a> Journal of Biomedical Optics. 21 (12), 126021 (2016).</li><li>Mesa, K., Rompolas, P., Zito, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Niche-induced+cell+death+and+epithelial+phagocytosis+regulate+hair+follicle+stem+cell+pool.">Niche-induced cell death and epithelial phagocytosis regulate hair follicle stem cell pool.</a> Nature. 522, 94-97 (2015).</li><li>Ral Li, ., 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=Pdgfra+marks+a+cellular+lineage+with+distinct+contributions+to+myofibroblasts+in+lung+maturation+and+injury+response.">Pdgfra marks a cellular lineage with distinct contributions to myofibroblasts in lung maturation and injury response.</a> eLife. 7, (2018).</li><li>Tal Tumbar, ., 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=Defining+the+epithelial+stem+cell+niche+in+skin.">Defining the epithelial stem cell niche in skin.</a> Science. 303 (5656), 359-363 (2004).</li><li>Ewald, A. J., Werb, Z., Egeblad, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+of+vital+signs+for+long-term+survival+of+mice+under+anesthesia.">Monitoring of vital signs for long-term survival of mice under anesthesia.</a> Cold Spring Harbor Protocols. 2 (2), 5563 (2011).</li><li>Sanderson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-photon+microscopy.">Multi-photon microscopy.</a> Current Protocols. 3 (1), 634 (2023).</li></ol>

The authors have no conflicts of interest to disclose.

In this study, we present a new tool that facilitates stable, long-term&#160;intravital imaging of intact mouse skin epithelia on inverted confocal microscopes. This invention is made of PLA, which is the most common and inexpensive 3D-printable material; all in-house 3D-printing costs for this insert amount to &#60;$5. The two separate insert pieces (Figure 1, Supplementary File 1, and Supplementary File 2) can be easily assembled using set screws (see <str...

Intravital microscopy is a powerful tool that allows the monitoring of cell behaviors in their unperturbed in vivo environments. This unique method has provided key insights into the inner workings of complex mammalian organ systems, including the lung1, brain2, liver3, mammary gland4, intestine5, and skin6. Furthermore, this approach has revealed cell behavioral alterations during tumor development7, wound healing8,9, inflammation10, and other diverse pathologies in situ. In this study, we focus on enhancing the accessibility of intravital microscopy to image live epithelial and stromal dynamics in intact mouse skin. Understanding cell behaviors in mammalian skin is of high clinical importance due to the remarkable regenerative and tumorigenic capacity of this tissue.
Intravital imaging in mice has&#160;been primarily performed using upright multiphoton microscopes due to their ability to provide high-resolution imaging at tissue depths &#62;100 &#181;m11,12. Nevertheless, these instruments&#160;lack the workhorse versatility and more general accessibility of inverted confocal microscopes, which are more user-friendly and cost-effective, provide the ability to image cultured cells, do not require complete darkness during image acquisition, and are generally safer, among other notable advantages13,14. In this study, we present a new tool that significantly enhances intravital imaging accessibility by adapting this approach for inverted confocal microscopes.
Here, we present a 3D-printed custom stage insert design that incorporates several key features to facilitate stable, long-term intravital imaging of mouse ear skin on an inverted confocal microscope (Figure 1, Figure 2, Figure 3, Figure 4, and Figure 5). These specialized features include an offset objective hole that allows the full body of an adult mouse to lay entirely flat during imaging. This minimizes the vibrational interference of mouse body movements on imaging and eliminates the need to administer ketamine and xylazine to dampen breathing, a practice often coupled with intravital imaging6. In addition, corner brackets on the insert correctly position an isoflurane nose cone to align with the face of the mouse, a metal ear clip immobilizes the mouse ear to a custom-built coverslip disk, and an optional detachable closed-loop biofeedback heat plate lies flush within the insert to support the mouse body temperature during long imaging sessions. The custom coverslip disk, which provides a flat surface essential for the mouse head and ear to lay flat, was generated in a machine shop by removing the walls of a generic coverslip-containing cell culture dish. The use of a 40x silicone oil immersion lens (1.25 numerical aperture [N.A.], 0.3 mm working distance) in conjunction with the coverslip disk and custom stage insert provides high resolution images &#62;50 &#181;m deep into the ear dermis.
To test the functionality of this new inverted microscope stage insert, we captured z-stacks spanning all epidermal epithelial layers over a 3 h time course in the ear of a live transgenic K14-H2B-mCherry15 adult mouse (epithelial nuclei in this mouse line contain a red fluorescent label) (Figure 6A-A&#39;). We also captured z-stacks spanning several fibroblast layers within the skin dermis over a 3 h time course in the ear of a live transgenic Pdgfra-rtTA16; pTRE-H2B-GFP17 adult mouse (fibroblast nuclei in this mouse line contain a green fluorescent label following doxycycline induction) (Figure 6B-D&#39;). Our high-resolution data demonstrate consistent stability by lack of drift in the x-, y-, and z-planes, thus proving the effectiveness of this new intravital imaging tool for use on inverted microscopes. Importantly, the dimensions of this 3D-printed stage insert can be adjusted, as described in Supplementary File 1, Supplementary File 2, and Supplementary File&#160;3, to fit any inverted microscope, and the positioning of the objective opening can be moved to alternative locations within the insert to better suit imaging a particular tissue and/or animal model of interest. This invention can thus empower individual laboratories, or investigators with core facility confocal access, to adapt this tool for their unique intravital imaging needs, thereby streamlining evaluation of diverse in vivo cell biology.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3D Printer</td>
			<td>Qudi Tech</td>
			<td>i-Fast</td>
			<td>3D prints using PLA material</td>
		</tr>
		<tr>
			<td>40x 1.25NA silicone objective lens</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>AxR Laser Scanning Confocal Microscope</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton Tipped Swab</td>
			<td>VWR</td>
			<td>76337-046</td>
			<td>Cream/ointment application</td>
		</tr>
		<tr>
			<td>Doxycycline hyclate</td>
			<td>Sigma-Aldrich</td>
			<td>D9891</td>
			<td>Induces GFP labeling of fibroblast nuclei in Pdgfra-rtTA; pTRE-H2B-GFP mice</td>
		</tr>
		<tr>
			<td>Flathead Screwdriver (2.5 mm)</td>
			<td></td>
			<td></td>
			<td>Affiix insert to microscope stage</td>
		</tr>
		<tr>
			<td>Flathead Screws x 4 (#6-32)</td>
			<td>Nikon</td>
			<td></td>
			<td>Screw insert into microscope stage</td>
		</tr>
		<tr>
			<td>Glass Bottom Culture Dish</td>
			<td>chemglass Life Sciences</td>
			<td>CLS-1811-002</td>
			<td>Modified by removing walls of dish for use as coverslip disk compatible with live insert; 35 mm wide disk contains 20 mm wide glass coverslip; dish walls were removed by machine shop</td>
		</tr>
		<tr>
			<td>Heat Plate controller</td>
			<td>Physitemp</td>
			<td>TCAT-2LV</td>
			<td>Animal Temperature Controller - Low Voltage; anal prob attachment for mouse body temperature monitoring</td>
		</tr>
		<tr>
			<td>Hex Wrench (1.5 mm)</td>
			<td></td>
			<td></td>
			<td>For M3 setscrew adjustments</td>
		</tr>
		<tr>
			<td>Hex Wrench (2.5 mm)</td>
			<td></td>
			<td></td>
			<td>Adjust tension on metal ear clip</td>
		</tr>
		<tr>
			<td>Intravital Imaging Insert</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Med-Vet International</td>
			<td>HPA030782-100uL</td>
			<td>Mouse anesthesia</td>
		</tr>
		<tr>
			<td>Labeling Tape (or Scotch Tape)</td>
			<td>VWR</td>
			<td>10127-458</td>
			<td>Alternative to metal ear clip to immobilize ear to coverslip</td>
		</tr>
		<tr>
			<td>Metal fastener</td>
			<td></td>
			<td></td>
			<td>used as ear clip</td>
		</tr>
		<tr>
			<td>Mouse: C57BL/6-Pdgfraem1(rtTA)Xsun/J</td>
			<td>The Jackson Laboratory</td>
			<td>RRID: IMSR_JAX:034459</td>
			<td>Fibrroblast-specific promoter driving doxycycline-inducible rtTA expression</td>
		</tr>
		<tr>
			<td>Mouse: K14-H2BPAmCherry</td>
			<td>Courtesy of Dr. Valentina Greco at Yale University</td>
			<td></td>
			<td>Labels epidermal epithelial cell nuclei with mCherry; referred to in text as &#34;K14-H2B-mCherry&#34;</td>
		</tr>
		<tr>
			<td>Mouse: pTRE-H2B-GFP: STOCK 
			Tg(tetO-HIST1H2BJ/GFP)47Efu/J</td>
			<td>The Jackson Laboratory</td>
			<td>RRID: IMSR_JAX:005104</td>
			<td>&#160;Labels fibroblast nuclei with GFP when combined with Pdgfra-rtTA and induced with doxycycline</td>
		</tr>
		<tr>
			<td>Multipurpose Sealing Wrap</td>
			<td>Glad</td>
			<td></td>
			<td>Enhance mouse warmth</td>
		</tr>
		<tr>
			<td>Optixcare</td>
			<td>VWR</td>
			<td>MSPP-078932779</td>
			<td>Eye lubricant</td>
		</tr>
		<tr>
			<td>Set screws x 3 (M3; 6 mm)</td>
			<td>Thorlabs</td>
			<td>SS3M6</td>
			<td>Attachment for heatplate module</td>
		</tr>
		<tr>
			<td>Silicone Immersion Oil</td>
			<td></td>
			<td></td>
			<td>Applied to 40x silicone objective</td>
		</tr>
		<tr>
			<td>Small Animal Heating Plate</td>
			<td>Physitemp</td>
			<td>HP-4M</td>
			<td>Provides heat to animal</td>
		</tr>
		<tr>
			<td>Somnoflow Low-Flow Electronic Vaporizer</td>
			<td>Kent Scientific</td>
			<td>SF-01</td>
			<td>Mouse anesthesia</td>
		</tr>
		<tr>
			<td>Vacuum Grease</td>
			<td>Flinn Scientific</td>
			<td>AP1095</td>
			<td>Seals coverslip disk to insert</td>
		</tr>
		<tr>
			<td>Veet</td>
			<td></td>
			<td></td>
			<td>hair removal&#160;</td>
		</tr>
		<tr>
			<td>Water circulating heat pad</td>
			<td>Stryker Medical</td>
			<td>TP700</td>
			<td>for mouse revival post-imaging</td>
		</tr>
	</tbody>
</table>

streamlined intravital imaging approach for long-term monitoring of epithelial tissue dynamics on an inverted confocal microscope

Understanding normal and aberrant in vivo cell behaviors is necessary to develop clinical interventions to thwart disease initiation and progression. It is therefore critical to optimize imaging approaches that facilitate the observation of cell dynamics in situ, where tissue structure and composition remain unperturbed. The epidermis is the body&#39;s outermost barrier, as well as the source of the most prevalent human cancers, namely cutaneous skin carcinomas. The accessibility of skin tissue presents a unique opportunity to monitor epithelial and dermal cell behaviors in intact animals using noninvasive intravital microscopy. Nevertheless, this sophisticated imaging approach has primarily been achieved using upright multiphoton microscopes, which represent a significant barrier for entry for most investigators. This study presents a custom-designed, 3D-printed microscope stage insert suitable for use with inverted confocal microscopes, streamlining the long-term intravital imaging of ear skin in live transgenic mice. We believe this versatile invention, which may be customized to fit the inverted microscope brand and model of choice and adapted to image additional organ systems, will prove invaluable to the greater scientific research community by significantly enhancing the accessibility of intravital microscopy. This technological advancement is critical for bolstering our understanding of live cell dynamics in normal and disease contexts.

Author Spotlight: Developing a Tool for Using Inverted Confocal Microscopes for In Vivo Intravital Imaging 

Streamlined Intravital Imaging Approach for Long-Term Monitoring of Epithelial Tissue Dynamics on an Inverted Confocal Microscope

We developed a tool to perform intravital imaging on live mice using an inverted confocal microscope. This enables us to track skin cell dynamics throughout homeostasis and compare cell behaviors during disease onset and progression. Multiphoton microscopy is the primary approach applied to achieve intravital cell tracking.However, the disadvantages of these microscopes include limited day-to-day imaging versatility, high cost, and technical complexity. Our new tool enables the use of versatile inverted confocal microscopes for in vivo intravital imaging. By modifying the design file, the stage insert dimensions can be customized to fit any make of inverted microscope.The objective hole can be resized and repositioned to fit any animal model and tissue of choice.

Proper assembly of the live imaging insert on an inverted confocal microscope and appropriate orientation of a transgenic mouse atop the insert is validated by acquiring z-stacks of fluorescently-labeled, live ear tissue over a time course &#8805;1 h with minimal evidence of drift in the x-, y-, and z-axes. Images should be captured at consistent intervals (interval time will depend on the biological question, strength of fluorescence&#160;signal, etc.) so that cell dynamics and image drift can be tracked over time. Thro...

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The protocol presents a new tool to simplify intravital imaging using inverted confocal microscopy.

Understanding normal and aberrant in vivo cell behaviors is necessary to develop clinical interventions to thwart disease initiation and progression. It ...

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Research

JoVE Journal

Biology

1.1K Views.  Emory University School of Medicine. We developed a tool to perform intravital imaging on live mice using an inverted confocal microscope. This enables us to track skin cell dynamics throughout homeostasis and compare cell behaviors during disease onset and progression. Multiphoton microscopy is the primary approach applied to achieve intravital cell tracking.However, the disadvantages of these microscopes include limited day-to-day imaging versatility, high cost, and technical complexity. Our new tool enables the use of ...

Video: Author Spotlight: Developing a Tool for Using Inverted Confocal Microscopes for In Vivo Intravital Imaging 

Installing the Live Imaging Insert on an Inverted Microscope Stage

To begin installing the 3D printed live imaging insert on the inverted microscope stage, carefully place the insert into the large microscope stage groove. Using screws, secure each corner of the insert. Slide the heat plate into the side opening of the insert in a plug side down orientation, so the plate lays atop the lower insert grooves with the plug port underneath the stage.Align the grooved circular opening in the insert with a 40 x silicone oil immersion objective and apply silicone oil to the center of the objective. Then using a syringe, apply a small amount of vacuum grease along the grooved circular opening. Lay the cover slip disk on top of the opening to seal it onto the insert.Finally, raise the 40 x objective until it barely touches the bottom of the glass cover slip.

Mounting the Mouse on the Live Imaging Insert for Intravital Imaging

Before placing the anesthetized mouse on the live imaging insert installed on the inverted microscope stage, thread the isoflurane tubing with the attached nose cone through the corner tubing bracket on the insert. After plugging the heat plate into the controller containing an attached anal thermometer probe and switching it on, transfer the anesthetized mouse from the induction chamber onto the heat plate. Then secure the nose cone onto the mouse.Insert the anal probe into the animal and adjust the controller to maintain a stable body temperature of about 36 degrees Celsius. Cover the properly-positioned mouse with a plastic cling wrap to trap body heat and elevate the body temperature. Position the mouse such that its head aligns with the cover slip disc and immobilize its ear onto the center of the glass cover slip using a metal ear clip or tape.After completing imaging, select the Low Flow option on the electronic vaporizer to cease isoflurane delivery. Transfer the mouse to a heating pad until it becomes ambulatory. After removing the cover slip disc, wipe it clean with lens paper and lens solution.Store it properly to avoid scratches for reuse. Next, detach the anesthetic tubing from the insert bracket and unscrew the insert from the microscope stage. The acquired Z-stacks of fluorescently-labeled live mouse ear tissue showed minimal drift in the x, y and z axes over time, validating the custom 3D printed live imaging inserts.The time points from a three hour time lapse movie of the mCherry positive mouse ear epidermal cells of an adult male mouse revealed a single z plane remaining in focus over the extended time. Similar observations were made from another three-hour time lapse movie of GFP positive ear dermal fibroblasts of an adult female mouse.