Scarring, naturally induced by fibroblasts(Fb) during wound healing, is an essential process in response to repair damaged tissue. Excessive Fb proliferation which produces the excessive collagen deposition, including increased extracellular matrix synthesis or insufficient decomposition, typically contributes to hypertrophic scar(HS) formation. Although exact mechanisms of HS are not yet fully understood, it is generally believed that dysfunction of Fb and regulation of signal pathways play an important role in HS formation. Biologically, Fb function is affected by various factors such as cytokines, extracellular matrix and itself. In addition, modifications of miRNA, ceRNA, lncRNA, peptides and histones participate in HS formation by affecting the biological function of Fb. Despite the clinical importance, very few therapeutic modalities are available to prevent HS. To achieve this, a deeper characterization of Fb is required to identify mechanisms of HS. To the aspect of HS prevention and treatment, we review recent findings, concentrating on Fb function and collagen secretion. The objective of this article is to frame the current understanding, gain the deeper insights into Fb function, and provide the more comprehensive cognition and perspective for prevention and treatment of HS.
Humans ; Cicatrix, Hypertrophic/metabolism* ; Collagen/therapeutic use* ; Fibroblasts ; Signal Transduction ; Extracellular Matrix/metabolism*

Hypertrophic scar is a pathological repair result of excessive accumulation of extracellular matrix after skin damage, which affects the appearance and function of patients with varying degrees. The degree of scar formation is directly related to the strength of inflammatory reaction during wound healing, and excessive or prolonged inflammatory response increases the incidence of hypertrophic scars. Interleukin-6 (IL-6) is a pleiotropic cytokine that is involved in regulating the fibrotic network composed of fibroblasts, macrophages, keratinocytes, and vascular endothelial cells, and is closely related to the formation of hypertrophic scars. This article reviews the role of IL-6 and its signaling pathway in hypertrophic scar formation.
Cicatrix, Hypertrophic/pathology* ; Endothelial Cells/metabolism* ; Fibroblasts/metabolism* ; Humans ; Interleukin-6 ; Skin/pathology* ; Wound Healing/physiology*

Objective: To investigate the regulatory effects and signaling mechanism of sodium ferulate on the proliferation and apoptosis of human skin hypertrophic scar fibroblasts (HSFbs). Methods: The experimental research methods were used. The 4^th-6^th passage of HSFbs from human skin were used for the following experiments. HSFbs were co-cultured with sodium ferulate at final mass concentrations of 1, 1×10^-1, 1×10^-2, 1×10^-3, 1×10^-4, 1×10^-5, and 1×10^-6 mg/mL for 48 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and linear regression was used to analyze the half lethal concentration (LC50) of sodium ferulate (n=6). HSFbs were co-cultured with sodium ferulate at final mass concentrations of 0.1, 0.2, 0.3, and 0.4 mg/mL for 24, 48, 72, and 96 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and the cell proliferation inhibition rate was calculated (n=3). According to the random number table, the cells were divided into 0.300 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, 0.003 mg/mL sodium ferulate group treated with sodium ferulate at corresponding final mass concentrations, and negative control group without any treatment. After 72 hours of culture, the cell absorbance values were determined by methyl thiazolyl tetrazolium method (n=5), the microscopic morphology of cells was observed by transmission electron microscope (n=3), the cell apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay and the apoptosis index was calculated (n=4), the protein expressions of B lymphocystoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and cysteine aspartic acid specific protease-3 (caspase-3) were determined by immunohistochemistry (n=4), and the protein expressions of transformed growth factor β₁ (TGF-β₁), phosphorylated Smad2/3, phosphorylated Smad4, and phosphorylated Smad7 were detected by Western blotting (n=4). Data were statistically analyzed with one-way analysis of variance and Dunnett test. Results: The LC50 of sodium ferulate was 0.307 5 mg/mL. After being cultured for 24-96 hours, the cell proliferation inhibition rates of cells treated with sodium ferulate at four different mass concentrations tended to increase at first but decrease later, which reached the highest after 72 hours of culture, so 72 hours was chosen as the processing time for the subsequent experiments. After 72 hours of culture, the cell absorbance values in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were 0.57±0.06, 0.53±0.04, 0.45±0.05, respectively, which were significantly lower than 0.69±0.06 in negative control group (P<0.01). After 72 hours of culture, compared with those in negative control group, the cells in the three groups treated with sodium ferulate showed varying degrees of nuclear pyknosis, fracture, or lysis, and chromatin loss. In the cytoplasm, mitochondria were swollen, the rough endoplasmic reticulum was expanded, and local vacuolation gradually appeared. After 72 hours of culture, compared with that in negative control group, the apoptosis indexes of cells were increased significantly in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group (P<0.05 or P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expressions of Bcl-2 of cells in 0.300 mg/mL sodium ferulate group was significantly decreased (P<0.01), the protein expressions of Bax of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.05), and the protein expression of caspase-3 of cells in 0.300 mg/mL sodium ferulate group was significantly increased (P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expression levels of TGF-β₁, phosphorylated Smad2/3, and phosphorylated Smad4 of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly decreased (P<0.05 or P<0.01), and the protein expression levels of phosphorylated Smad7 of cells in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.01). Conclusions: Sodium ferulate can inhibit the proliferation of HSFbs of human skin and promote the apoptosis of HSFbs of human skin by blocking the expression of key proteins on the TGF-β/Smad signaling pathway and synergistically activating the mitochon- drial apoptosis pathway.
Apoptosis ; Caspase 3/metabolism* ; Cell Proliferation ; Cicatrix, Hypertrophic/metabolism* ; Coumaric Acids ; Fibroblasts/metabolism* ; Humans ; Signal Transduction ; bcl-2-Associated X Protein/pharmacology*

OBJECTIVES: Steroidal anti-inflammatory drugs have certain side effects in the treatment of hypertrophic scar, and the scar recurrence is easy after withdrawal of steroid anti-inflammatory drugs. Finding reliable alternative drugs is an effective means to improve this defect. Aspirin, a traditional non-steroidal anti-inflammatory drug, is safe for topical use and has anti-inflammatory effects similar to those of steroidal anti-inflammatory drugs, which may have similar effects on the treatment of hypertrophic scar. This study aims to investigate the inhibitory effect of aspirin on the proliferation of hypertrophic scar in rabbit ears and the underlying mechanism. METHODS: The rabbit ear hypertrophic scar models were prepared. The rabbits were randomly divided into a normal skin group (group A), a blank control group (group B), a 0.9% NaCl group (group C), a 0.2% aspirin group (group D), a 0.5% aspirin group (group E), a 2% aspirin group (group F), and a triamcinolone acetonide group (group G). Macroscopic observation of hyperplasia was performed 8 weeks after local injection of the scar, followed by collecting the scar tissue samples for HE staining, Masson staining, and immunohistochemistry, respectively to assess the proliferation of fibroblasts and collagen fibers, and calculate the hypertrophic index, microvessel density, and immunohistochemical score. RESULTS: All rabbit ear hypertrophic scar models were successfully constructed. In groups B and C, the hypertrophic scar edge was irregular, with reddish protruding epidermis, significant contracture and hard touch. In group D, E, and F, with the increase of aspirin administration concentration, the scar became thinner and gradually flat, the proliferation of fibrocytes and collagen fibers was weakened, and the hypertrophic index was gradually decreased (P<0.05). Immunohistochemistry showed that the expression of β-catenin was decreased in the group D, E and F in turn, and the immunohistochemical score was gradually decreased (P<0.05). There was no significant difference in hypertrophic index, microvessel density, and immunohistochemical score (all P>0.05). CONCLUSIONS Local injection of aspirin can reduce the generation of hypertrophic scar in a dose-dependent manner within a certain concentration range; aspirin inhibits the growth of hypertrophic scar in rabbit ears by inhibiting Wnt/β-catenin signal pathway; 2% aspirin and 40 mg/mL triamcinolone acetonide have similar curative efficacy on hypertrophic scar.
Animals ; Anti-Inflammatory Agents/therapeutic use* ; Aspirin/therapeutic use* ; Cicatrix, Hypertrophic/pathology* ; Collagen ; Rabbits ; Signal Transduction ; Triamcinolone Acetonide/therapeutic use* ; beta Catenin/metabolism*

Objective: To explore the effect of microRNA(miR)-222 on cell proliferation and apoptosis of fibroblasts in hypertrophic scar (HS) and the underlying mechanisms. Methods: The expression of miR-222 in the HS and the normal skin tissues was detected by real-time RT-PCR. The HS fibroblasts were transfected with miR-222 mimic and miR-222 inhibitor respectively. The cell viability was tested with MTT assay, cell cycle distribution and apoptosis were detected with flow cytometry and the expression levels of proliferation, apoptosis and cell cycle related proteins were determined with Western blot. Direct target of miR-222 was evaluated by dual-luciferase reporter assay. Results: miR-222 was significantly up-regulated in HS tissues compared with normal skin tissues(P<0.05). Overexpression of miR-222 enhanced the cell viability of HS fibroblasts; increased mRNA and protein expressions of proliferating cell nuclear antigen (PCNA), collagen alpha-1 (Ⅰ) chain (Col1A1) and collagen alpha-1 (Ⅲ) chain (Col3A1); increased cell population in S phase and protein expressions of cyclin D1, cyclin E1 and cyclin-dependent kinases 1 (CDK1); inhibited cell apoptosis and reduced protein expressions of caspase-3/9. Overexpression of MMP1 attenuated the effects of miR-222 on the cell viability and apoptosis in fibroblasts, reduced expression levels of PCNA, cyclin D1 and the expression of caspase-3 was increased. Conclusion: miR-222 enhances cell proliferation and inhibits cell apoptosis of HS fibroblasts through negative regulation of MMP1, which suggests that miR-222 and MMP1 might be used as novel biomarkers and targets in diagnostic and therapeutic approaches for HS.
Apoptosis ; genetics ; Cell Proliferation ; genetics ; Cicatrix, Hypertrophic ; Fibroblasts ; Humans ; Matrix Metalloproteinase 1 ; metabolism ; MicroRNAs ; metabolism

This research was aimed to study the effect of Emodin gel on the hypertrophic scars of rabbit ears. A total of 18 rabbits were randomly divided into Emodin group (9 rabbits) and control group (9 rabbits) after the successful animal model for hypertrophic scars had been made. The rabbits in the Emodin group were treated with Emodin Gel, while no special treatment was given to those in the control group. The other living conditions were all kept the same in the two groups. The diameter,hardness, and expression of transforming growth factor-beta (TGF-beta) and interleukin-1 (IL-1) of hypertrophic scars were measured after 4 weeks. Transmission electron microscopy was applied to observe the ultra-structure of the fibroblasts of hypertrophic scars. But there was no difference between the two groups in the diameter of hypertrophic scars (P>0.05). The hardness, expression of TGF-beta and IL-1 in hypertrophic scars in the Emodin group decreased, compared to the control group (P<0.05, P<0.01, P<0.05). Transmission electron microscopy showed that the fibroblast and organelle lessened in the cytoplasm and the collagen fibers dissolved obviously. The study showed that Emodin gel decreased the hardness of hypertrophic scars in the rabbit ears, and inhibited the proliferation of fibroblasts in local area. Therefore, Emodin gel treatment would be one of the methods to prevent and treat hypertrophic scars.
Animals ; Cicatrix, Hypertrophic ; drug therapy ; Cytoplasm ; Disease Models, Animal ; Emodin ; pharmacology ; Fibroblasts ; drug effects ; Gels ; Hardness ; Interleukin-1 ; metabolism ; Microscopy, Electron, Transmission ; Rabbits ; Transforming Growth Factor beta ; metabolism

BACKGROUNDHypertrophic scar is one of the most common complications and often causes the disfigurement or deformity in burn or trauma patients. Therapeutic methods on hypertrophic scar treatment have limitations due to the poor understanding of mechanisms of hypertrophic scar formation. To throw light on the molecular mechanism of hypertrophic scar formation will definitely improve the outcome of the treatment. This study aimed to illustrate the negative role of eukaryotic initiation factor 6 (eIF6) in the process of human hypertrophic scar formation, and provide a possible indicator of hypertrophic scar treatment and a potential target molecule for hypertrophic scar.

METHODSIn the present study, we investigated the protein expression of eIF6 in the human hypertrophic scar of different periods by immunohistochemistry and Western blot analysis.

RESULTSIn the hypertrophic scar tissue, eIF6 expression was significantly decreased and absent in the basal layer of epidermis in the early period, and increased slowly and began to appear in the basal layer of epidermis by the scar formation time.

CONCLUSIONSThis study confirmed that eIF6 expression was significantly related to the development of hypertrophic scar, and the eIF6 may be a target molecule for hypertrophic scar control or could be an indicator of the outcomes for other treatment modalities.

Adult ; Blotting, Western ; Cicatrix, Hypertrophic ; metabolism ; Female ; Gene Expression Regulation ; genetics ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Peptide Initiation Factors ; metabolism ; Pregnancy ; Retrospective Studies ; Young Adult

OBJECTIVETo study the role of integrin-linked kinase (ILK) on the proliferation and differentiation of human fibroblast in hypertrophic scar and its effect on the scar formation.

METHODSThe human scar fibroblasts were isolated and cultured in vitro. The cells were divided into 4 groups. (1) control group: only contains DMEM; (2) jetPRIME group: DMEM with 200 microl jetPRIME buffer and 4 microl jetPRIME; (3) ILK siRNA group: DMEM and ILK siRNA; (4) ILK cDNA group: DMEM and ILK cDNA. The cell proliferation was detected by XTT assay and the mRNA and protein expressions of ILK and alpha-SMA were detected by Real-time qPCR and Western blot.

RESULTS(1) XTT results showed that the cellular proliferation level after 48 h in four groups were 0.820 +/- 0.065, 0.873 +/- 0.041, 0.554 +/- 0.013 and 1.296 +/- 0.094, respectively. The cellular proliferation curve showed that the cellular proliferation level was very flat in ILK siRNA group while the cellular proliferation level gradually increased from 12 h. 48 h after transfection, the cellular proliferation level in ILK siRNA group was significant lower than those in other groups (P value were 0.021, 0.034, 0), while the cellular proliferation level in ILK cDNA group was the highest among all 4 groups (P value were 0.017, 0.009, 0). (2) The Real-time qPCR showed that the expressions of ILK mRNA and alpha-SMA mRNA were 0.693 +/- 0.412 and 0.422 +/- 0.037 in control group, were 0.621 +/- 0.183 and 0.388 +/- 0.005 in jetPRIME group, were 0.052 +/- 0.019 and 0.073 +/- 0.023 in ILK siRNA group, were 240.193 +/- 35.170 and 138.056 +/- 24.060 in ILK cDNA group. The expressions of ILK mRNA and alpha-SMA mRNA in ILK siRNA group were significantly lower than those in other three groups (P < 0.05). And the expressions of ILK mRNA and alpha-SMA mRNA in ILK cDNA group were significantly higher than those in other three groups (P < 0.05). (3) The Western blot also showed that the expression of ILK and alpha-SMA proteins were decreased in ILK siRNA group and increased in ILK cDNA group.

CONCLUSIONILK may promote the proliferation and differentiation of human scar fibroblast. It may play an important role in scar formation and contracture.

Actins ; metabolism ; Adolescent ; Adult ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cicatrix, Hypertrophic ; metabolism ; Female ; Fibroblasts ; cytology ; drug effects ; metabolism ; Humans ; Male ; Middle Aged ; Protein-Serine-Threonine Kinases ; pharmacology ; RNA, Messenger ; genetics ; Transfection ; Young Adult

OBJECTIVETo explore the CD phenotypic, protein expression and pluripotent differentiation of human hypertrophic scar fibroblasts cultured in vitro, so as to study the mechanisms of scar formation.

METHODSFibroblasts were isolated and cultured from human hypertrophic scar of 3 cases. The cells morphology was observed by inverted microscope, and the growing state of the third passage was detected by the cell counting meter of Vi-CELL. The cell surface markers CD105, CD14, CD73, CD34, CD44, CD45 and CD90 were identified by flow cytometry. The expression of CK19, Oct-4, Nanog and vimentin was detected by immunocytochemistry, and the expression of alpha-smooth muscle actin(alpha-SMA) was tested by immunofluorescence. The differentiated potential of fibroblasts of the third passage into adipogenic, osteogenic and chondrogenic lineages was assayed.

RESULTSThe primary passage fibroblasts showed the shape of spindle shaped or irregular polygon with a radiated or circinate of growing arrangement. The growth curve showed the cells growth was slow on the first and second day, and quick during the third to fifth day, which reached platform stage on the sixth or seventh day. The fibroblasts highly expressed mesenchymal stem cell surface markers-CD73, CD105, CD44, CD90, but not expressed hematopoietic stem cell surface markers-CD14, CD34, CD45 by flow cytometry. And positive expression of vimentin, Oct-4 and negative expression of CK19 were detected by Immunocytochemistry. Positive expression of alpha-SMA was also detected by immunofluorescence. Multidirectional differentiation induction indicated that the third passage cells could differentiate into adipogenic, osteogenic and chondrogenic lineages.

CONCLUSIONSHuman hypertrophic scar-derived fibroblasts show the biologic characteristics of mesenchymal stem cells, which may play an important role in wound healing and hypertrophic scar formation.

Adolescent ; Antigens, CD ; metabolism ; Cell Differentiation ; physiology ; Cells, Cultured ; Cicatrix, Hypertrophic ; pathology ; Female ; Fibroblasts ; cytology ; metabolism ; Humans ; Male ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Phenotype ; Young Adult

OBJECTIVETo study the effects of peroxisome proliferator-activated receptor gamma agonists on angiotensin II-induced cellular response in cultured fibroblasts derived from patients with hypertrophic scars, so as to investigate its effects on preventing the formation of hypertrophic scars.

METHODSFibroblasts were freshly isolated from hypertrophic scars and cultured with angiotensin II, rosiglitazone and GW9662 at a certain concentration. Fibroblasts proliferation were assessed via Cell Counting Kit-8; the mRNA and protein expressions of Collagen I and Fibronectin (FN) were determined by quantitative real-time RT-PCR and Western blotting.

RESULTSThe absorbance of CCK-8 and relative expression of Collagen I, FN mRNA and protein were 1.082 5 +/- 0.007, 6.45 +/- 0.97, 4.92 +/- 0.86, 2.92 +/- 0.41, 2.78 +/- 1.04 in Ang II group; 0.722 4 +/- 0.012, 1.82 +/- 0.34, 1.78 +/- 0.27, 1.57 +/- 0.46, 1.68 +/- 0.39 in Ros + Ang II group; 0.554 7 +/- 0.012, 0.97 +/- 0.12, 1.07 +/- 1.08, 1.05 +/- 0.43, 1.14 +/- 0.36 in Ros group; 1.056 0 +/- 0.005, 5.83 +/- 0.24, 4.47 +/- 0.32, 2.69 +/- 0.35, 2.62 +/- 0.27 in GW9662 + ros + Ang II group. The results showed a significant difference between the Ang II group and the control group (P < 0.05). The effect of Ang II could be markedly inhibited by Ros (P < 0.05). In addition, Ros did not influence cell proliferation and production of extracellular matrix (P > 0.05). There was a significant difference between the GW9662 + Ros + Ang II group and the Ros + Ang II (P < 0.05).

CONCLUSIONSPPAR-gamma agonists inhibit Ang II-induced proliferation and extracellular matrix synthesis effectively in the hypertrophic scar fibroblasts. Thus PPAR-gamma agonists may have potential therapeutic effect for hypertrophic scar.

Angiotensin II ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cicatrix, Hypertrophic ; metabolism ; Collagen Type I ; biosynthesis ; Extracellular Matrix ; drug effects ; Fibroblasts ; drug effects ; metabolism ; pathology ; Fibronectins ; biosynthesis ; Humans ; PPAR gamma ; agonists