This work was supported by grants from the National Natural Science Foundation of China (grant numbers 81903189 and 82073418) and the Science and Technology Foundation of Guangzhou (grant number 202102020025).

This study was approved by the institutional review board of the Dermatology Hospital, Southern Medical University (2020081). Informed patient consent was obtained before tissues were collectedfrom the individuals.
1. Preparation
NOTE: The following procedures should be performed in a sterile environment under a biological safety cabinet.
<ol>
	<li>Prepare complete culture medium by adding 10% fetal bovine serum (FBS) and 1% penicillin-streptomyci...

<ol>
	<li>Zhu, Y. Q., 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=Genome-wide+analysis+of+Chinese+keloid+patients+identifies+novel+causative+genes.">Genome-wide analysis of Chinese keloid patients identifies novel causative genes.</a> Annals Of Translational Medicine. 10 (16), 883 (2022).</li><li>Feng, F., 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=Biomechanical+regulatory+factors+and+therapeutic+targets+in+keloid+fibrosis.">Biomechanical regulatory factors and therapeutic targets in keloid fibrosis.</a> Frontiers in Pharmacology. 13, 906212 (2022).</li><li>Cohen, A. J., Nikbakht, N., Uitto, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Keloid+disorder:+Genetic+basis,+gene+expression+profiles,+and+immunological+modulation+of+the+fibrotic+processes+in+the+skin.">Keloid disorder: Genetic basis, gene expression profiles, and immunological modulation of the fibrotic processes in the skin.</a> Cold Spring Harbor Perspectives in Biology. , (2022).</li><li>Wang, W., 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=Current+advances+in+the+selection+of+adjuvant+radiotherapy+regimens+for+keloid.">Current advances in the selection of adjuvant radiotherapy regimens for keloid.</a> Frontiers in Medicine. 9, 1043840 (2022).</li><li>Ghadiri, S. J., Kloczko, E., Flohr, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topical+treatments+in+the+management+of+keloids+and+hypertrophic+scars:+A+critically+appraised+topic.">Topical treatments in the management of keloids and hypertrophic scars: A critically appraised topic.</a> British Journal of Dermatology. 187 (6), 855-856 (2022).</li><li>Neves, L. M. G., Wilgus, T. A., Bayat, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro,+ex+vivo,+and+in+vivo+approaches+for+investigation+of+skin+scarring:+Human+and+animal+models.">In vitro, ex vivo, and in vivo approaches for investigation of skin scarring: Human and animal models.</a> Advances in Wound Care. 12 (2), 97-116 (2023).</li><li>Supp, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+for+studies+of+keloid+scarring.">Animal models for studies of keloid scarring.</a> Advances in Wound Care. 8 (2), 77-89 (2019).</li><li>K&#252;nzel, S. R., 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=Ultrasonic-augmented+primary+adult+fibroblast+isolation.">Ultrasonic-augmented primary adult fibroblast isolation.</a> Journal of Visualized Experiments. (149), e59858 (2019).</li><li>He, Y., 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=An+improved+explants+culture+method:+Sustainable+isolation+of+keloid+fibroblasts+with+primary+characteristics.">An improved explants culture method: Sustainable isolation of keloid fibroblasts with primary characteristics.</a> Journal of Cosmetic Dermatology. 21 (12), 7131-7139 (2022).</li><li>Philippeos, C., 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=Spatial+and+single-cell+transcriptional+profiling+identifies+functionally+distinct+human+dermal+fibroblast+subpopulations.">Spatial and single-cell transcriptional profiling identifies functionally distinct human dermal fibroblast subpopulations.</a> Journal of Investigative Dermatology. 138 (4), 811-825 (2018).</li><li>Li, L., 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=Hydrogen+sulfide+suppresses+skin+fibroblast+proliferation+via+oxidative+stress+alleviation+and+necroptosis+inhibition.">Hydrogen sulfide suppresses skin fibroblast proliferation via oxidative stress alleviation and necroptosis inhibition.</a> Medicine and Cellular Longevity. 2022, 7434733 (2022).</li><li>Zhou, B. Y., 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=Nintedanib+inhibits+keloid+fibroblast+functions+by+blocking+the+phosphorylation+of+multiple+kinases+and+enhancing+receptor+internalization.">Nintedanib inhibits keloid fibroblast functions by blocking the phosphorylation of multiple kinases and enhancing receptor internalization.</a> Acta Pharmacologica Sinica. 41 (9), 1234-1245 (2020).</li><li>Wang, X. M., Liu, X. M., Wang, Y., Chen, Z. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activating+transcription+factor+3+(ATF3)+regulates+cell+growth,+apoptosis,+invasion+and+collagen+synthesis+in+keloid+fibroblast+through+transforming+growth+factor+beta+(TGF-beta)/SMAD+signaling+pathway.">Activating transcription factor 3 (ATF3) regulates cell growth, apoptosis, invasion and collagen synthesis in keloid fibroblast through transforming growth factor beta (TGF-beta)/SMAD signaling pathway.</a> Bioengineered. 12 (1), 117-126 (2021).</li><li>Sato, C., 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=Conditioned+medium+obtained+from+amnion-derived+mesenchymal+stem+cell+culture+prevents+activation+of+keloid+fibroblasts.">Conditioned medium obtained from amnion-derived mesenchymal stem cell culture prevents activation of keloid fibroblasts.</a> Plastic and Reconstructive Surgery. 141 (2), 390-398 (2018).</li><li>Li, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+explant+culture:+An+improved+method+for+consistently+harvesting+homogeneous+populations+of+keloid+fibroblasts.">Long-term explant culture: An improved method for consistently harvesting homogeneous populations of keloid fibroblasts.</a> Bioengineered. 13 (1), 1565-1574 (2022).</li><li>Wang, Q., 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=Altered+glucose+metabolism+and+cell+function+in+keloid+fibroblasts+under+hypoxia.">Altered glucose metabolism and cell function in keloid fibroblasts under hypoxia.</a> Redox Biology. 38, 101815 (2021).</li><li>Fan, C., 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=Single-cell+transcriptome+integration+analysis+reveals+the+correlation+between+mesenchymal+stromal+cells+and+fibroblasts.">Single-cell transcriptome integration analysis reveals the correlation between mesenchymal stromal cells and fibroblasts.</a> Frontiers in Genetics. 13, 798331 (2022).</li><li>Yao, L., 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=Temporal+control+of+PDGFR&#945;+regulates+the+fibroblast-to-myofibroblast+transition+in+wound+healing.">Temporal control of PDGFR&#945; regulates the fibroblast-to-myofibroblast transition in wound healing.</a> Cell Reports. 40 (7), 111192 (2022).</li><li>Domdey, 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=Consecutive+dosing+of+UVB+irradiation+induces+loss+of+ABCB5+expression+and+activation+of+EMT+and+fibrosis+proteins+in+limbal+epithelial+cells+similar+to+pterygium+epithelium.">Consecutive dosing of UVB irradiation induces loss of ABCB5 expression and activation of EMT and fibrosis proteins in limbal epithelial cells similar to pterygium epithelium.</a> Stem Cell Research. 40, 102936 (2022).</li><li>Lin, Z., 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=Renal+tubular+epithelial+cell+necroptosis+promotes+tubulointerstitial+fibrosis+in+patients+with+chronic+kidney+disease.">Renal tubular epithelial cell necroptosis promotes tubulointerstitial fibrosis in patients with chronic kidney disease.</a> FASEB Journal. 36 (12), e22625 (2022).</li><li>Korosec, 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=Lineage+identity+and+location+within+the+dermis+determine+the+function+of+papillary+and+reticular+fibroblasts+in+human+skin.">Lineage identity and location within the dermis determine the function of papillary and reticular fibroblasts in human skin.</a> Journal of Investigative Dermatology. 139 (2), 342-351 (2019).</li></ol>

There are no conflicts of interest to declare.

Obtaining primary fibroblasts from keloid tissues is a critical basis for further research. Up until now, there have been two methods for acquiring primary fibroblasts: enzyme digestion and explant culture11,12,13,14. However, both traditional methods have limitations, such as susceptibility to contamination, mixing with other types of cells, a long culture period, and a low rate of success<sup...

Keloid, a fibroproliferative disease, manifests as the continuous growth of plaques that often invade the surrounding normal skin without self-limitation and cause various degrees of itching, pain, and cosmetic and psychological burdens for patients1. Fibroblasts, the primary cells involved in keloids, play an essential role in the formation and development of this disease through excessive proliferation, redundant extracellular matrix production, and disorganized collagens2,3. However, the underlying pathogenesis remains unclear, and an effective therapeutic method for keloid is still lacking; therefore, there is an urgent need for further research4,5.
As there is no ideal animal model for keloid research in vivo6,7,building an in vitro model by acquiring primary fibroblasts from keloid tissues can offer feasibility and reliability for keloid research2,6. Primary cells are those derived directly from living tissue, and it is generally recognized that these cells can more closely resemble the physiological state and genetic background of multiple individuals compared with cell lines8,9. Culturing primary cells provides a powerful means to study the growth and metabolism of cells, as well as other cell phenotypes.
At present, there are two methods for acquiring primary fibroblasts: enzyme digestion and explant culture. However, several obstacles have been identified to obtaining primary fibroblasts, such as the risk of contamination by various bacteria or fungi, mixing with other types of cells that are not easily removed, the long period of the culture cycle, the subsequent changes to the cell characteristics compared to the original cells, and so on9. Therefore, developing a feasible and effective process for obtaining primary fibroblasts is the foundation for further studies and applications.This study describes an optimized protocol for extracting primary fibroblasts from keloid tissues that can effectively and steadily provide pure and viable fibroblasts.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1.5 mL sterile centrifuge tube</td>
			<td>JETBIOFIL</td>
			<td>CFT002015</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL sterile centrifuge tube</td>
			<td>JETBIOFIL</td>
			<td>8076</td>
			<td></td>
		</tr>
		<tr>
			<td>4% polyformaldehyde</td>
			<td>Beyotime Biotechnology</td>
			<td>P0099</td>
			<td>Cell fixation</td>
		</tr>
		<tr>
			<td>50 mL sterile centrifuge tube</td>
			<td>JETBIOFIL</td>
			<td>8081</td>
			<td>Put keloid tissue</td>
		</tr>
		<tr>
			<td>Alexa Fluor-555 goat anti-rabbit IgG&#160;</td>
			<td>Abcam</td>
			<td>Alexa&#160;Fluor&#160;555&#160;</td>
			<td>second antibody for immunofluorescence staining assay</td>
		</tr>
		<tr>
			<td>Anti human CD90</td>
			<td>BioLegend</td>
			<td>B301002</td>
			<td>Identify the purity of fibroblasts</td>
		</tr>
		<tr>
			<td>Antibody diluent</td>
			<td>Beyotime Biotechnology</td>
			<td>P0262</td>
			<td></td>
		</tr>
		<tr>
			<td>Biological safety cabinet&#160;</td>
			<td>Thermo Scientific</td>
			<td>1300 series A2</td>
			<td>Isolation and culture cells</td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>aladdin</td>
			<td>B265993</td>
			<td>Blocking for immunofluorescence staining assay</td>
		</tr>
		<tr>
			<td>Carbon dioxide incubator</td>
			<td>ESCO</td>
			<td>CCL-170B-8</td>
			<td>Using for culturing cells</td>
		</tr>
		<tr>
			<td>Cell cryotubes</td>
			<td>Corning</td>
			<td>43513</td>
			<td>Store the cells in low temperature</td>
		</tr>
		<tr>
			<td>centrifugal machine</td>
			<td>Thermo Fisher</td>
			<td>ST 16R</td>
			<td>Discard supernatant&#160;</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Beyotime Biotechnology</td>
			<td>C1006</td>
			<td>Stain the cellular nucleus</td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>MP Biomedicals</td>
			<td>196055</td>
			<td>Using for preserving cells</td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s modified eagle medium</td>
			<td>Gibco</td>
			<td>C11995500BT</td>
			<td>Culture medium solution</td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>BI</td>
			<td>04-001-1A</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cytometer</td>
			<td>BD</td>
			<td>BD FACSCelesta</td>
			<td>Observing the identity of cells</td>
		</tr>
		<tr>
			<td>frozen box</td>
			<td>Thermo Scientific</td>
			<td>&#160;5100-0050</td>
			<td></td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Nikon</td>
			<td>ECLIPSE Ts2</td>
			<td></td>
		</tr>
		<tr>
			<td>Laser confocal microscope</td>
			<td>Nikon</td>
			<td>AIR-HD25</td>
			<td>Observing the immunofluorescence staining assay</td>
		</tr>
		<tr>
			<td>PDGFR-&#945; antibody</td>
			<td>CST</td>
			<td>3174T</td>
			<td>First antibody for immunofluorescence staining assay</td>
		</tr>
		<tr>
			<td>Penicillin-streptomycin-Am solution</td>
			<td>Solarbio</td>
			<td>P1410</td>
			<td>Add in culture medium solution to avoid contamination</td>
		</tr>
		<tr>
			<td>petri dish</td>
			<td>JETBIOFIL</td>
			<td>7556</td>
			<td>Culture fibroblasts</td>
		</tr>
		<tr>
			<td>Phosphate buffered saline solution</td>
			<td>Gibco</td>
			<td>C10010500BT</td>
			<td>Culture medium solution</td>
		</tr>
		<tr>
			<td>Rabbit (DAIE) mAB IgG XR (R) Isotuge Control (PE)</td>
			<td>Cell Signaling Technology</td>
			<td>5742S</td>
			<td>As a control for flow cytometry</td>
		</tr>
		<tr>
			<td>Round coverslip</td>
			<td>Biosharp</td>
			<td>801007</td>
			<td>Cell culture</td>
		</tr>
		<tr>
			<td>Triton X 100</td>
			<td>Solarbio</td>
			<td>T8200</td>
			<td>Punch holes in the cell membrane</td>
		</tr>
		<tr>
			<td>Trypsin-EDTA</td>
			<td>Gibco</td>
			<td>25200072</td>
			<td>Used for passaging cells</td>
		</tr>
		<tr>
			<td>Vimentin antibody</td>
			<td>Abcam</td>
			<td>ab8978</td>
			<td>First antibody for immunofluorescence staining assay</td>
		</tr>
	</tbody>
</table>

isolation, culture, and characterization of primary dermal fibroblasts from human keloid tissue

Fibroblasts, the major cell type in keloid tissue, play an essential role in the formation and development&#160;of keloids. The isolation and culture of primary fibroblasts derived from keloid tissue are the basis for further studies of the biological function and molecular mechanisms of keloids, as well as new therapeutic strategies for treating them. The traditional method of obtaining primary fibroblasts has limitations, such as poor cellular state, mixing with other types of cells, and susceptibility to contamination. This paper describes an optimized and easily reproducible protocol that could reduce the occurrence of possible issues when obtaining fibroblasts. In this protocol, fibroblasts can be observed 5 days after isolation and reach nearly 80% confluency after 10 days of culture. Then, the fibroblasts are passaged and verified using PDGFR&#945; and vimentin antibodies for immunofluorescence assays and CD90 antibodies for flow cytometry. In conclusion, fibroblasts from keloid tissue can be easily acquired through this protocol, which can provide an abundant and stable source of cells in the laboratory for keloid research.

The timeline of the protocol is summarized in Figure 1A. Some representative images of the isolation process are shown in Figure 2; the epidermis and adipose layers were carefully removed, and the dermis layer was separated into small fragments of 3-4 mm2, which were inoculated into the Petri dishes.
As shown in Figure 3A, several fibroblast outgrowths of the tissue pieces were observed und...

Watch this Scientific Journal Video about Isolation, Culture, and Characterization of Primary Dermal Fibroblasts from Human Keloid Tissue at JoVE.com

Isolation, Culture, and Characterization of Primary Dermal Fibroblasts from Human Keloid Tissue

This study describes an optimized protocol for establishing primary fibroblasts from keloid tissues that can effectively and steadily provide pure and viable fibroblasts.

Fibroblasts, the major cell type in keloid tissue, play an essential role in the formation and development&#160;of keloids. The isolation and culture of ...

The isolation and culture of primary fibroblasts derived from keloid tissue are the basis for further studies of keloids. Fibroblasts from keloid tissue can be easily acquired through this protocol, which can provide an abundant and stable source of cells in the laboratory for keloid research. Begin by using sterile tweezers to place the keloid tissue in a 50 milliliter sterile centrifuge tube containing 10 to 25 milliliters of PBS supplemented with 1%PSA.Meanwhile, add four milliliters of PBS PSA solution to each well of a six-well plate. Now take the tissue out of the tube, and wash twice with PBS PSA solution. Using a pair of sterile forceps, transfer the tissue sequentially from one well to the next.Then remove the adipose and epidermis layers with surgical scissors, leaving the dermis untouched. Use a pair of scissors to dissect the trimmed dermis into three to five square millimeter pieces and transfer the pieces to the next well with a pair of sterile forceps. Wash the pieces in PBS PSA solution.Using sterilized forceps, place 10 to 30 dermis tissue pieces spaced less than five millimeters apart in Petri dishes. Place the dishes upside down in an incubator until the pieces dry and stick to the dish. Next, add seven milliliters of DMEM supplemented with 10%FBS and 1%PSA, and incubate the dishes as before.After three days, replace half the supernatant with complete culture medium. Observe the fibroblasts daily under 40X microscopic magnification. Remove the tissue pieces in the culture medium when the fibroblasts reach 90%confluency.Wash the fibroblasts in PBS and add two milliliters of sterile trypsin EDTA solution. After incubating the cells in a humidified incubator, gently tap the culture dish and observe it under the microscope. Add two milliliters of complete medium to end to the digestion once most of the cells have detached.Now transfer the cell suspension to a 15 milliliter sterile centrifuge tube and centrifuge the tube at 300G for three minutes at room temperature. Discard the supernatant carefully and resuspend the cell pellet in complete medium. Seed the fibroblasts into a nine centimeter cell culture dish and incubate in a humidified incubator.To perform immunofluorescent analysis after culturing the fibroblasts on round coverslips and incubating them in primary and secondary antibodies, add 50 microliters of DAPI solution to the glass slide to stain the cellular nuclei. Place the washed coverslips on glass slides using forceps. Finally, transfer the samples to a wet dark box for fluorescent microscopy.Fibroblast outgrowths of the tissue were observed at five days after processing. The fibroblasts displayed high proliferation rates and reached confluency after 10 days. The fibroblasts had elongated and spindle-like cell bodies, which were aligned in bundles at high confluency.Immunofluorescent staining returned positive red immunofluorescence of the fibroblasts and blue immunofluorescence of the cellular nucleus. Flow cytometric assays showed CD90 positivity in almost all fibroblasts. This study has described an optimized method and provided clear instructions to solve existing challenges and increase the chance of success for the isolation and culture of keloid fibroblasts.

isolation-culture-characterization-primary-dermal-fibroblasts-from

Research

JoVE Journal

Medicine

1.7K Views.  Southern Medical University. The isolation and culture of primary fibroblasts derived from keloid tissue are the basis for further studies of keloids. Fibroblasts from keloid tissue can be easily acquired through this protocol, which can provide an abundant and stable source of cells in the laboratory for keloid research. Begin by using sterile tweezers to place the keloid tissue in a 50 milliliter sterile centrifuge tube containing 10 to 25 milliliters of PBS supplemented with 1%PSA.Meanwhile, add four milliliter...