This work was funded by the friends of Sophia Foundation (SSWO WAR-63).

All zebrafish husbandry and experiments were conducted according to the institutional guidelines of the Erasmus MC and Animal welfare legislation. The use of zebrafish larvae at 5 days post fertilization falls under the category of experiments that do not require formal ethical approval, as outlined by the Dutch regulations.
1. Obtaining 5 days post fertilization (dpf) wildtype and tg(phox2bb:GFP) larvae
<ol>
	<li>Set up breeding of wildtype zebrafish and collect 50 eggs in HEPES-buffered E3 medium (hereafter referred to as E3) in a 15 cm Petri dish. Use these fish as a negative control for fluorescence-activated cell sorting (FACs).</li>
	<li>Set up breeding of tg(phox2bb:GFP) zebrafish and collect approximately 300 eggs in E3 in a 15 cm Petri dish.</li>
	<li>Keep fertilized eggs in E3 (maximum 50 eggs/dish) on a 14 h/10 h light/dark cycle, in an incubator at 28.5 &#176;C.</li>
	<li>At 1 dpf, remove unfertilized eggs and let the fertilized ones develop to 5 dpf.</li>
	<li>Select tg(phox2bb:GFP) larvae at 1 dpf.</li>
</ol>
2. Wildtype whole larvae dissociation
<ol>
	<li>Anesthetize 5 dpf larvae with 0.016% Tricaine.</li>
	<li>Chop 30 zebrafish into small pieces using a razor blade in a Petri dish containing 1 mL of 10x trypsin-EDTA solution.</li>
	<li>Transfer the chopped zebrafish into a microcentrifuge tube with a total volume of 2 mL of 10x trypsin-EDTA solution and leave on ice for 3 h. Pipette up and down with a P1000 pipette every hour to stimulate dissociation.</li>
</ol>
3. Gut isolation
<ol>
	<li>Place 6-10 5 dpf larvae anesthetized with 0.016% Tricaine in a row, on a 1.8% agarose plate (0.45 g of agarose in 25 mL of E3), under a dissection microscope</li>
	<li>Put one insect pin in the head of the zebrafish.</li>
	<li>Remove all remaining E3 using a tissue.</li>
	<li>Isolate the intestine using another insect pin, without disturbing any other organs. Make sure that the yolk is removed (Supplementary Figure S1A).</li>
	<li>Once isolated, inspect the intestine and remove all non-intestinal material (e.g., skin, fat, liver) if needed.</li>
	<li>Collect the intestine with tweezers and place it in a microcentrifuge tube, containing phosphate-buffered saline (PBS) with 10% fetal calf serum (FCS), on ice. 
	&#8203;NOTE: A minimum of 244 intestines should be isolated, keeping the total dissection time at 3 h. This is feasible with two people working in parallel.</li>
</ol>
4. Gut dissociation
<ol>
	<li>Immediately after the dissection of all intestines, centrifuge the microcentrifuge tube at full speed (13,800 &#215; g) for 30 s.</li>
	<li>Remove the PBS/10% FCS but leave a small amount (~100 &#181;L) to prevent the intestines from drying out. Add 500 &#181;L of 2.17 mg/mL papain in HBSS containing CaCl2 and MgCl2, to dissociate cells.</li>
	<li>Activate papain with 2.5 &#181;L of cysteine (1 M).</li>
	<li>Incubate the guts in a water bath at 37 &#176;C for 10 min. Pipette up and down halfway (after 5 min) to stimulate enzymatic tissue digestion.</li>
	<li>Transfer cells into a FACS tube using a 35 &#181;m cell strainer, prewetted with 0.5 mL of PBS/10% FCS.</li>
	<li>Wash the strainer by adding a total of 2 mL of PBS/10% FCS in 0.5 mL steps.</li>
	<li>Centrifuge at 700 &#215; g for 5 min at 4 &#176;C.</li>
	<li>Remove the supernatant and resuspend the pellet in 300 &#181;L of PBS/10% FCS.</li>
	<li>Add 1 &#181;g/mL of 4&#39;,6-diamidino-2-phenylindole (DAPI) to label dead cells (1:1,000) and incubate for 5 min to allow their exclusion during FACS.</li>
</ol>
5. FACS enrichment
<ol>
	<li>Use the wildtype sample to set the gates of the sorted cell population by recording 3,000 cells on the flow cytometer (Supplementary Figure S1B-E).</li>
	<li>Use a 100 &#181;m nozzle, set sort precision on purity, and put the collection tube containing 200 &#181;L of PBS/5% FCS, in the FACS machine.</li>
	<li>Load the cell suspension of the guts and sort live (DAPI-negative), single cells into the collection tube (Figure 2C), by excluding doublets (Figure 2B) and dead cells (Figure 2C). 
	NOTE: For the tg(phox2bb) zebrafish, the proportion of GFP+ cells is only checked for reference, as all single live cells are sorted.</li>
	<li>Keep the collection tube on ice after cell sorting.</li>
	<li>Count the cell suspension with a hemocytometer, including a viability check with trypan blue. If the viability is at least 80%, continue with the next step.</li>
	<li>Cells are now ready to process for scRNAseq (i.e., 10x Genomics Chromium platform). Use approximately 20,000 cells per sample.</li>
</ol>

Processing Gut Cells from Zebrafish Larvae for Single-Cell RNA Sequencing

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	<li>Saldana-Morales, F. B., Kim, D. V., Tsai, M. T., Diehl, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Healthy+intestinal+function+relies+on+coordinated+enteric+nervous+system,+immune+system,+and+epithelium+eesponses.">Healthy intestinal function relies on coordinated enteric nervous system, immune system, and epithelium eesponses.</a> Gut Microbes. 13 (1), 1-14 (2021).</li><li>Sitrin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Gastrointestinal System. , (2014).</li><li>Furness, J. 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The authors have no conflicts of interest to disclose.

Here, we present a method for isolation and dissociation of the gut of 5 dpf zebrafish larvae using FACS. With this method, different intestinal cell types were successfully collected and analyzed by scRNA-seq, using the 10x Genomics Chromium platform. We selected the tg(phox2bb:GFP) zebrafish line, as we wanted an indication that viable ENS cells would be also isolated (Figure 2D). However, it is important to note that this method can be readily extended to other zebrafish lines of...

The gastrointestinal (GI) tract is a complex system that plays a vital role in overall health and well-being. It is responsible for the digestion and absorption of nutrients, as well as the elimination of waste products1,2. The GI tract is composed of multiple cell types, including epithelial cells, smooth muscle cells, immune cells, and the enteric nervous system (ENS), which communicate closely together to regulate and maintain proper intestinal function3,4,5. Defects in the development of the GI tract can have far-reaching effects on various aspects such as nutrient absorption, microbiota composition, the gut-brain axis, and the ENS, leading to several enteric neuromuscular disorders, such as Hirschsprung disease and Chronic intestinal pseudo-obstruction6,7. These disorders are characterized by severe gut dysmotility caused by alterations in various key cells, such as the interstitial cells of Cajal, smooth muscle cells, and the ENS6,8,9. However, the molecular mechanisms underlying GI development and dysfunction are still poorly understood.
The zebrafish is a valuable model organism for studying GI development and dysfunction due to its rapid embryonic development, transparency during embryonic and larval stages, and genetic tractability10,11,12,13,14. Numerous transgenic zebrafish lines expressing fluorescent proteins are available. An example of such a line is the tg(phox2bb:GFP) zebrafish, commonly used to study the ENS, as all phox2bb+ cells, including enteric neurons, are labeled15,16. Here, using the tg(phox2bb:GFP) zebrafish line, we present a method for intestinal isolation of 5 days post fertilization (dpf) larvae for single-cell RNA sequencing (scRNA-seq) analysis (Figure 1).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>10x Trypsin (0.5%)-EDTA (0.2%)</td>
			<td>Sigma</td>
			<td>59418C</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL round bottom tube with cell-strainer cap</td>
			<td>Falcon</td>
			<td>352235</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Sigma-Aldrich</td>
			<td>A9539</td>
			<td></td>
		</tr>
		<tr>
			<td>BD Falcon Round-Bottom Tube 5 mL (FACS tubes) snap cap</td>
			<td>BD Biosciences</td>
			<td>352054</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell Ranger v3.0.2</td>
			<td>10X Genomics</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Sigma-Aldrich</td>
			<td>Cat#D-9542</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissection microscope</td>
			<td>Olympus SZX16</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>FACSAria III sorter machine</td>
			<td>BD Biosciences</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS with CaCl2 and MgCl2</td>
			<td>Gibco</td>
			<td>14025050</td>
			<td></td>
		</tr>
		<tr>
			<td>Insect pins</td>
			<td>Fine Science Tools</td>
			<td>26000-25</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Cysteine</td>
			<td>Sigma</td>
			<td>C7352</td>
			<td></td>
		</tr>
		<tr>
			<td>MS-222, Tricaine</td>
			<td>Supelco</td>
			<td>A5040-250G</td>
			<td></td>
		</tr>
		<tr>
			<td>Papain</td>
			<td>Sigma</td>
			<td>P4762</td>
			<td></td>
		</tr>
		<tr>
			<td>Seurat v3</td>
			<td>Stuart et&#160;al. (2019)</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue&#160;</td>
			<td>Sigma&#160;</td>
			<td>Cat#T8154</td>
			<td></td>
		</tr>
	</tbody>
</table>

gut isolation from zebrafish larvae for single-cell rna sequencing

The gastrointestinal (GI) tract performs a range of functions essential for life. Congenital defects affecting its development can lead to enteric neuromuscular disorders, highlighting the importance to understand the molecular mechanisms underlying GI development and dysfunction. In this study, we present a method for gut isolation from zebrafish larvae at 5 days post fertilization to obtain live,&#160;viable cells which can be used for single-cell RNA sequencing (scRNA-seq) analysis. This protocol is based on the manual dissection of the zebrafish intestine, followed by enzymatic dissociation with papain. Subsequently, cells are submitted to fluorescence-activated cell sorting, and viable cells are collected for scRNA-seq. With this method, we were able to successfully identify different intestinal cell types, including epithelial, stromal, blood, muscle, and immune cells, as well as enteric neurons and glia. Therefore, we consider it to be a valuable resource for studying the composition of the GI tract in health and disease, using the zebrafish.

With this protocol, we achieved successful isolation and dissociation of entire intestines from 5 dpf&#160;larvae. Using papain as the dissociation enzyme, we significantly enhanced cell viability, enabling the capture of 46,139 events involving single, viable cells (6.4% of all cells) out of 244 isolated guts (Figure 2A). Wildtype whole larvae were used as a control to ensure that the sorting process was optimized, enabling effective cell identification and sorting. Whole larvae could be us...

Watch this Scientific Journal Video about Isolating and Analyzing Intestinal Cells of Zebrafish Larvae for Investigating Transcriptomic Aspects of Gastrointestinal Development at JoVE.com

Author Spotlight: Isolating and Analyzing Intestinal Cells of Zebrafish Larvae for Investigating Transcriptomic Aspects of Gastrointestinal Development 

Here, we describe a method for gut isolation from zebrafish larvae at 5 days post fertilization, for single-cell RNA sequencing analysis.

Gut Isolation from Zebrafish Larvae for Single-cell RNA Sequencing

The gastrointestinal (GI) tract performs a range of functions essential for life. Congenital defects affecting its development can lead to enteric ...

gut-isolation-from-zebrafish-larvae-for-single-cell-rna-sequencing

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JoVE Journal

Developmental Biology

1.5K Views.  Erasmus University Medical Center - Sophia Children's Hospital. Here, we describe a method for gut isolation from zebrafish larvae at 5 days post fertilization, for single-cell RNA sequencing analysis.

Video: Author Spotlight: Isolating and Analyzing Intestinal Cells of Zebrafish Larvae for Investigating Transcriptomic Aspects of Gastrointestinal Development 

Capturing Tissue Repair in Zebrafish Larvae with Time-lapse Brightfield Stereomicroscopy

The zebrafish larval tail fin is ideal for studying tissue regeneration due to the simple architecture of the larval fin-fold, which comprises of two layers of skin that enclose undifferentiated mesenchyme, and because the larval tail fin regenerates rapidly within 2-3 days. Using this system, we demonstrate a method for capturing the repair dynamics of the amputated tail fin with time-lapse video brightfield stereomicroscopy. We demonstrate that fin amputation triggers a contraction of the amputation wound and extrusion of cells around the wound margin, leading to their subsequent clearance. Fin regeneration proceeds from proximal to distal direction after a short delay. In addition, developmental growth of the larva can be observed during all stages. The presented method provides an opportunity for observing and analyzing whole tissue-scale behaviors such as fin development and growth in a simple microscope setting, which is easily adaptable to any stereomicroscope with time-lapse capabilities.

We present a protocol for capturing the dynamics of zebrafish larval tail fin regeneration on a whole-tissue scale using brightfield-based stereomicroscopy. This technique enables capturing the regeneration dynamics with single cell resolution. This methodology can be adapted to any stereomicroscope equipped with a CCD camera and time-lapse software.

The zebrafish larval tail fin is ideal for studying tissue regeneration due to the simple architecture of the larval fin-fold, which comprises of two ...

Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye

The zebrafish model is an emerging system for the study of neuromuscular disorders. In the study of neuromuscular diseases, the integrity of the muscle membrane is a critical disease determinant. To date, numerous neuromuscular conditions display degenerating muscle fibers with abnormal membrane integrity; this is most commonly observed in muscular dystrophies. Evans Blue Dye (EBD) is a vital, cell permeable dye that is rapidly taken into degenerating, damaged, or apoptotic cells; in contrast, it is not taken up by cells with an intact membrane. EBD injection is commonly employed to ascertain muscle integrity in mouse models of neuromuscular diseases. However, such EBD experiments require muscle dissection and/or sectioning prior to analysis. In contrast, EBD uptake in zebrafish is visualized in live, intact preparations. Here, we demonstrate a simple and straightforward methodology for performing EBD injections and analysis in live zebrafish. In addition, we demonstrate a co-injection strategy to increase efficacy of EBD analysis. Overall, this video article provides an outline to perform EBD injection and characterization in zebrafish models of neuromuscular disease.

In this study, we describe a straightforward method to perform Evans Blue Dye (EBD) analysis on zebrafish larvae. This technique is a powerful tool for the characterization of skeletal muscle integrity and delineation of zebrafish models of muscular dystrophy, and is a valuable method for the development of novel therapeutics.

The zebrafish model is an emerging system for the study of neuromuscular disorders.  In the study of neuromuscular diseases, the integrity of the muscle ...

Isolation and Characterization of Single Cells from Zebrafish Embryos

The zebrafish (Danio rerio) is a powerful model organism to study vertebrate development. Though many aspects of zebrafish embryonic development have been described at the morphological level, little is known about the molecular basis of cellular changes that occur as the organism develops. With recent advancements in microfluidics and multiplexing technologies, it is now possible to characterize gene expression in single cells. This allows for investigation of heterogeneity between individual cells of specific cell populations to identify and classify cell subtypes, characterize intermediate states that occur during cell differentiation, and explore differential cellular responses to stimuli. This study describes a protocol to isolate viable, single cells from zebrafish embryos for high throughput multiplexing assays. This method may be rapidly applied to any zebrafish embryonic cell type with fluorescent markers. An extension of this method may also be used in combination with high throughput sequencing technologies to fully characterize the transcriptome of single cells. As proof of principle, the relative abundance of cardiac differentiation markers was assessed in isolated, single cells derived from nkx2.5 positive cardiac progenitors. By evaluation of gene expression at the single cell level and at a single time point, the data support a model in which cardiac progenitors coexist with differentiating progeny. The method and work flow described here is broadly applicable to the zebrafish research community, requiring only a labeled transgenic fish line and access to microfluidics technologies.

This protocol describes a method for isolating single cells from zebrafish embryos, enriching for cells of interest, capturing zebrafish cells in microfluidic based single cell multiplex systems, and assessing gene expression from single cells.

The zebrafish (Danio rerio) is a powerful model organism to study vertebrate development. Though many aspects of zebrafish embryonic development have been ...

Microstructured Devices for Optimized Microinjection and Imaging of Zebrafish Larvae

Zebrafish have emerged as a powerful model of various human diseases and a useful tool for an increasing range of experimental studies, spanning fundamental developmental biology through to large-scale genetic and chemical screens. However, many experiments, especially those related to infection and xenograft models, rely on microinjection and imaging of embryos and larvae, which are laborious techniques that require skill and expertise. To improve the precision and throughput of current microinjection techniques, we developed a series of microstructured devices to orient and stabilize zebrafish embryos at 2 days post fertilization (dpf) in ventral, dorsal, or lateral orientation prior to the procedure. To aid in the imaging of embryos, we also designed a simple device with channels that orient 4 zebrafish laterally in parallel against a glass cover slip. Together, the tools that we present here demonstrate the effectiveness of photolithographic approaches to generate useful devices for the optimization of zebrafish techniques.

Microinjection of zebrafish embryos and larvae is a crucial but challenging technique used in many zebrafish models. Here, we present a range of microscale tools to aid in the stabilization and orientation of zebrafish for both microinjection and imaging.

Zebrafish have emerged as a powerful model of various human diseases and a useful tool for an increasing range of experimental studies, spanning ...

Single-cell Photoconversion in Living Intact Zebrafish

Animal and plant tissue is composed of distinct populations of cells. These cells interact over time to build and maintain the tissue and can cause disease when disrupted. Scientists have developed clever techniques to investigate characteristics and natural dynamics of these cells within intact tissue by expressing fluorescent proteins in subsets of cells. However, at times, experiments require more selected visualization of cells within the tissue, sometimes at the single-cell or population-of-cells manner. To achieve this and visualize single cells within a population of cells, scientists have utilized single-cell photoconversion of fluorescent proteins. To demonstrate this technique, we show here how to direct UV light to an Eos-expressing cell of interest in an intact, living zebrafish. We then image those photoconverted Eos+ cells 24 h later to determine how they changed in the tissue. We describe two techniques: single cell photoconversion and photoconversions of populations of cell. These techniques can be used to visualize cell-cell interactions, cell-fate and differentiation, and cell migrations, making it a technique that is applicable in numerous biological questions.

Here, we present a protocol to show how cell photoconversion is achieved through UV exposure to specific areas expressing the fluorescent protein, Eos, in living animals.

Animal and plant tissue is composed of distinct populations of cells. These cells interact over time to build and maintain the tissue and can cause ...

Whole Mount Immunohistochemistry in Zebrafish Embryos and Larvae

Immunohistochemistry is a widely used technique to explore protein expression and localization during both normal developmental and disease states. Although many immunohistochemistry protocols have been optimized for mammalian tissue and tissue sections, these protocols often require modification and optimization for non-mammalian model organisms. Zebrafish are increasingly used as a model system in basic, biomedical, and translational research to investigate the molecular, genetic, and cell biological mechanisms of developmental processes. Zebrafish offer many advantages as a model system but also require modified techniques for optimal protein detection. Here, we provide our protocol for whole-mount fluorescence immunohistochemistry in zebrafish embryos and larvae. This protocol additionally describes several different mounting strategies that can be employed and an overview of the advantages and disadvantages each strategy provides. We also describe modifications to this protocol to allow detection of chromogenic substrates in whole mount tissue and fluorescence detection in sectioned larval tissue. This protocol is broadly applicable to the study of many developmental stages and embryonic structures.

Here, we present a protocol for fluorescent antibody-mediated detection of proteins in whole preparations of zebrafish embryos and larvae.

Immunohistochemistry is a widely used technique to explore protein expression and localization during both normal developmental and disease states. ...

Multiplexed Single Cell mRNA Sequencing Analysis of Mouse Embryonic Cells

Single cell mRNA sequencing has made significant progress in the last several years and has become an important tool in the field of developmental biology. It has been successfully used to identify rare cell populations, discover novel marker genes, and decode spatial and temporal developmental information. The single cell method has also evolved from the microfluidic based Fluidigm C1 technology to the droplet-based solutions in the last two to three years. Here we used the heart as an example to demonstrate how to profile the mouse embryonic tissue cells using the droplet based scRNA-Seq method. In addition, we have integrated two strategies into the workflow to profile multiple samples in a single experiment. Using one of the integrated methods, we have simultaneously profiled more than 9,000 cells from eight heart samples. These methods will be valuable to the developmental biology field by providing a cost-effective way to simultaneously profile single cells from different genetic backgrounds, developmental stages, or anatomical locations.

Here we presented a multiplexed single cell mRNA sequencing method to profile gene expression in mouse embryonic tissues. The droplet-based single cell mRNA sequencing (scRNA-Seq) method in combination with multiplexing strategies can profile single cells from multiple samples simultaneously, which significantly reduces reagent costs and minimizes experimental batch effects.

Single cell mRNA sequencing has made significant progress in the last several years and has become an important tool in the field of developmental ...

Preparation of Small RNA Libraries for Sequencing from Early Mouse Embryos

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs during early development are technically challenging due to the limiting cell number. Moreover, many approaches require a miRNA of interest to be defined in assays such as northern blotting, microarray, and qPCR. Therefore, the expression of many miRNAs and their isoforms have not been studied during early development. Here, we demonstrate a protocol for small RNA sequencing of sorted cells from early mouse embryos to enable relatively unbiased profiling of miRNAs in early populations of neural crest cells. We overcome the challenges of low cell input and size selection during library preparation using amplification and gel-based purification. We identify embryonic age as a variable accounting for variation between replicates and stage-matched mouse embryos must be used to accurately profile miRNAs in biological replicates. Our results suggest that this method can be broadly applied to profile the expression of miRNAs from other lineages of cells. In summary, this protocol can be used to study how miRNAs regulate developmental programs in different cell lineages of the early mouse embryo.

We describe a technique for profiling microRNAs in early mouse embryos. This protocol overcomes the challenge of low cell input and small RNA enrichment. This assay can be used to analyze changes in miRNA expression over time in different cell lineages of the early mouse embryo.

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs ...

Isolation of Murine Retinal Endothelial Cells for Next-Generation Sequencing

Recent improvements in next-generation sequencing have advanced researchers&#39; knowledge of molecular and cellular biology, with several studies revealing novel paradigms in vascular biology. Applying these methods to models of vascular development requires the optimization of cell isolation techniques from embryonic and postnatal tissues. Cell yield, viability, and purity all need to be maximal to obtain accurate and reproducible results from next-generation sequencing approaches. The neonatal mouse retinal vascularization model is used by researchers to study mechanisms of vascular development. Researchers have used this model to investigate mechanisms of angiogenesis and arterial-venous fate specification during blood vessel formation and maturation. Applying next-generation sequencing techniques to study the retinal vascular development model requires optimization of a method for the isolation of retinal endothelial cells that maximizes cell yield, viability, and purity. This protocol describes a method for murine retinal tissue isolation, digestion, and purification using fluorescence-activated cell sorting (FACS). The results indicate that the FACS-purified CD31+/CD45- endothelial cell population is highly enriched for endothelial cell gene expression and exhibits no change in viability for 60 min post-FACS. Included are representative results of next-generation sequencing approaches on endothelial cells isolated using this method, including bulk RNA sequencing and single-cell RNA sequencing, demonstrating that this method for retinal endothelial cell isolation is compatible with next-generation sequencing applications. This method of retinal endothelial cell isolation will allow for advanced sequencing techniques to reveal novel mechanisms of vascular development.

This protocol describes a method for the isolation of murine postnatal retinal endothelial cells optimized for cell yield, purity, and viability. These cells are suitable for next-generation sequencing approaches.

Recent improvements in next-generation sequencing have advanced researchers&#39; knowledge of molecular and cellular biology, with several studies ...

Using Alizarin Red Staining to Detect Chemically Induced Bone Loss in Zebrafish Larvae

Chemically induced bone loss due to lead (Pb) exposure could trigger an array of adverse impacts on both human and animal skeletal systems. However, the specific effects and mechanisms in zebrafish remain unclear. Alizarin red has a high affinity for calcium ions and can help visualize the bone and illustrate skeletal mineral mass. In this study, we aimed to detect lead acetate (PbAc)-induced bone loss in zebrafish larvae by using alizarin red staining. Zebrafish embryos were treated with a series of PbAc concentrations (0, 5, 10, 20 mg/L) between 2 and 120 h post fertilization. Whole-mount skeletal staining was conducted on larvae at 9 days post fertilization, and the total stained area was quantified using ImageJ software. The results indicated that the mineralized tissues were stained in red, and the stained area decreased significantly in the PbAc-exposure group, with a dose-dependent change in bone mineralization. This paper presents a staining protocol for investigating skeletal changes in PbAc-induced bone defects. The method can also be used in zebrafish larvae for the detection of bone loss induced by other chemicals.

Here, we have used alizarin red staining to show that lead acetate exposure causes a bone mass change in zebrafish larvae. This staining method can be adapted to the investigation of bone loss in zebrafish larvae loss induced by other hazardous toxicants.

Chemically induced bone loss due to lead (Pb) exposure could trigger an array of adverse impacts on both human and animal skeletal systems. However, the ...