Full-thickness Skin Defect Wound Research Articles

Effect of Bovine Lactoferrin Treatment on Iron Homeostasis and Gene Expression Changes in Multiple Organ Dysfunctions During Wound Healing Process in Rats.

Injury systemically disrupts the homeostatic balance and can cause organ failure. LF mediates both iron-dependent and iron-independent mechanisms, and the role of LF in regulating iron homeostasis is vital in terms of metabolism. In this study, we evaluated the organ-level effect and gene expression change of bLf in the cutaneous repair process. An excisional full-thickness skin defect (FTSD) wound model was created in male Sprague Dawley rats (180-250 g) (n = 48) fed a high-fat diet (HFD) and the PHGPx, SLC7A11 and SLC40A1 genes and iron metabolism were evaluated. The animals were randomly divided into 6 groups: 1- Control, 2- bLf (200 mg/kg/day, oral), 3- FTSD (12 mm in diameter, dorsal), 4- HFD + bLf, 5- HFD + FTSD, 6- HFD + FTSD + bLf. Histologically, iron accumulation was demonstrated by Prussian blue staining in the liver, kidney, and intestinal tissues. Gene expression analysis was performed with qPCR. Histologically, iron accumulation was demonstrated by Prussian blue staining in the liver, kidney, and intestinal tissues. Prussian blue reactions were detected in the kidney. PHPGx and SLC7A11 genes in kidney and liver tissue were statistically significant (P < 0.05) except for the SLC40A1 gene (P > 0.05). Expression changes of the three genes were not statistically significant in analyses of rat intestinal tissue (P = 0.057). In the organ-level ferroptotic damage mechanism triggered by wound formation. BLf controls the expression of three genes and manages iron deposition in these three tissues. In addition, it suppressed the increase in iron that would drive the cell to ferroptosis and anemia caused by inflammation, thereby eliminating iron deposition in the tissues.

Tannic acid-modified acellular dermal matrix dressings for promoting full-thickness wound healing

Wound healing is a significant clinical and public health concern, and wound dressings are currently the primary method for addressing it. This study aimed to develop a multifunctional, all-natural wound dressing with antibacterial and anti-inflammatory properties using porcine acellular dermal matrix (PADM), a bioderived material that closely resembles the structure of human skin. The cells were decellularized using hypertonic salt and strong alkaline to remove immunogenicity while retaining the extracellular matrix. Subsequently, the wound dressing was prepared through tannic acid modification. In vitro cytotoxicity, scratch, anti-inflammatory, and antibacterial tests were used to assess the multifunctionality of the biomaterials. A full-thickness skin defect wound was created in rats, and the wound healing was analyzed using gross and histological staining. The results indicated that tannic acid-modified acellular dermal matrix exhibits favorable mechanical properties and biocompatibility. In vitro experiments demonstrated its effective inhibition of the growth of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. It can downregulate nitric oxide (NO) production and the expression levels of pro-inflammatory factors in macrophages stimulated by lipopolysaccharide. In vitro experiments demonstrated that the dressing can enhance wound healing. Therefore, tannic acid-modified acellular dermal matrix accelerates wound healing through anti-inflammatory and antibacterial effects. Its excellent properties make it a potential biological material for promoting wound healing.

Visible-Light Cross-Linkable Multifunctional Hydrogels Loaded with Exosomes Facilitate Full-Thickness Skin Defect Wound Healing through Participating in the Entire Healing Process.

The management of severe full-thickness skin defect wounds remains a challenge due to their irregular shape, uncontrollable bleeding, high risk of infection, and prolonged healing period. Herein, an all-in-one OD/GM/QCS@Exo hydrogel was prepared with catechol-modified oxidized hyaluronic acid (OD), methylacrylylated gelatin (GM), and quaternized chitosan (QCS) and loaded with adipose mesenchymal stem cell-derived exosomes (Exos). Cross-linking of the hydrogel was achieved using visible light instead of ultraviolet light irradiation, providing injectability and good biocompatibility. Notably, the incorporation of catechol groups and multicross-linked networks in the hydrogels conferred strong adhesion properties and mechanical strength against external forces such as tensile and compressive stress. Furthermore, our hydrogel exhibited antibacterial, anti-inflammatory, and antioxidant properties along with wound-healing promotion effects. Our results demonstrated that the hydrogel-mediated release of Exos significantly promotes cellular proliferation, migration, and angiogenesis, thereby accelerating skin structure reconstruction and functional recovery during the wound-healing process. Overall, the all-in-one OD/GM/QCS@Exo hydrogel provided a promising therapeutic strategy for the treatment of full-thickness skin defect wounds through actively participating in the entire process of wound healing.

Effects of applying human umbilical cord mesenchymal stem cell exosomes through different pathways to treat full-thickness skin defect wounds in mice

Objective: To investigate the effects of human umbilical cord mesenchymal stem cell (hUCMSC) exosomes in the treatment of full-thickness skin defect wounds in mice through local wound application, subcutaneous injection at the wound margin, and tail vein injection, and to explore the optimal administration route of hUCMSC exosomes for wound treatment. Methods: This study was an experimental study. hUCMSC exosomes were extracted from the discarded umbilical cord tissue of three normal delivery women aged 25-35 years in the Department of Obstetrics and Gynecology of Baogang Hospital of Inner Mongolia and successfully identified. Totally 120 male BALB/c mice aged 6-8 weeks were selected, and full-thickness skin defect wounds were prepared on the back of them. According to the random number table, the injured mice were divided into control group (without drug administration), local wound application group, wound margin subcutaneous injection group, and tail vein injection group (with 30 mice in each group). Mice in the latter three groups were given 0.2 mL phosphate buffer solution containing 200 μg hUCMSC exosomes by local wound application, subcutaneous injection at the wound margin, and tail vein injection, respectively. On post injury day (PID) 7, 14, and 21, the general condition of the wound was observed, and the wound healing rate was calculated; the wound tissue was collected, the pathological changes and collagen fibers were observed respectively by hematoxylin-eosin staining and Masson staining, the number of new microvessels was observed by CD31 immunohistochemical staining, and the content of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) was detected by enzyme-linked immunosorbent assay. The sample number was 10 in each group at each time point. Results: On PID 7, 14, and 21, the wounds of mice in the 4 groups all healed gradually, and the wound healing of the mice in wound margin subcutaneous injection group was the best; the wound healing rates of mice in the three administration groups were significantly higher than those in control group (P<0.05), the wound healing rates of mice in wound margin subcutaneous injection group and tail vein injection group were significantly higher than those in local wound application group (P<0.05), and the wound healing rates of mice in wound margin subcutaneous injection group were significantly higher than those in tail vein injection group (P<0.05). On PID 7, 14, and 21, the growth and epithelialization speed of the wound tissue of mice in the three administration groups were significantly accelerated, and the collagen fibers in the wounds of mice in the three administration groups were larger in number and more neatly arranged in comparison with the control group. On PID 7, 14, and 21, under every 200-fold visual field, the number of new microvessels in the wound tissue of mice in local wound application group was 24.1±2.5, 50.7±4.1, and 44.2±2.3, respectively, the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group was 32.2±2.9, 67.5±4.9, and 53.6±3.7, respectively, and the number of new microvessels in the wound tissue of mice in tail vein injection group was 27.8±2.4, 59.1±3.7, and 49.6±2.6, respectively, which was significantly more than 20.6±1.7, 46.7±3.4, and 40.9±2.8 in control group (P<0.05); the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group and tail vein injection group was significantly more than that in local wound application group (P<0.05); the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group was significantly more than that in tail vein injection group (P<0.05). On PID 7, 14, and 21, the content of TNF-α and IL-6 in the wound tissue of mice in the three administration groups was significantly less than that in control group (P<0.05), the content of TNF-α and IL-6 in the wound tissue of mice in wound margin subcutaneous injection group and tail vein injection group was significantly less than that in local wound application group (P<0.05), and the content of TNF-α and IL-6 in the wound tissue of mice in wound margin subcutaneous injection group was significantly less than that in tail vein injection group (P<0.05). Conclusions: Local wound application, subcutaneous injection at the wound margin, and tail vein injection of hUCMSC exosomes can all promote the wound healing of full-thickness skin defects in mice through alleviating excessive inflammatory response and promoting angiogenesis. Among them, subcutaneous injection at the wound margin has a better therapeutic effect, indicating subcutaneous injection at the wound margin is the optimal administration route for hUCMSC exosomes in wound treatment.

Effects of gelatin methacrylate anhydride hydrogel loaded with small extracellular vesicles derived from human umbilical cord mesenchymal stem cells in the treatment of full-thickness skin defect wounds in mice

Objective: To investigate the effects of gelatin methacrylate anhydride (GelMA) hydrogel loaded with small extracellular vesicles derived from human umbilical cord mesenchymal stem cells (hUCMSCs-sEVs) in the treatment of full-thickness skin defect wounds in mice. Methods: This study was an experimental study. hUCMSCs-sEVs were extracted by ultracentrifugation, their morphology was observed through transmission electron microscope, and the expression of CD9, CD63, tumor susceptibility gene 101 (TSG101), and calnexin was detected by Western blotting. The human umbilical vein endothelial cells (HUVECs), the 3rd and 4th passages of human epidermal keratinocytes (HEKs) and human dermal fibroblasts (HDFs) were all divided into blank control group (routinely cultured) and hUCMSC-sEV group (cultured with the cell supernatant containing hUCMSCs-sEVs). The cell scratch test was performed and the cell migration rates at 6, 12, and 24 h after scratching were calculated, the cell Transwell assay was performed and the number of migration cells at 12 h after culture was calculated, and the proportion of proliferating cells was detected by 5-acetylidene-2'-deoxyuridine and Hoechst staining at 24 h after culture, with sample numbers being all 3. The simple GelMA hydrogel and the GelMA hydrogel loaded with hUCMSCs-sEVs (hereinafter referred to as hUCMSC-sEV/GelMA hydrogel) were prepared. Then the micromorphology of 2 kinds of hydrogels was observed under scanning electron microscope, the distribution of hUCMSCs-sEVs was observed by laser scanning confocal microscope, and the cumulative release rates of hUCMSCs-sEVs at 0 (immediately), 2, 4, 6, 8, 10, and 12 d after soaking hUCMSC-sEV/GelMA hydrogel in phosphate buffer solution (PBS) were measured and calculated by protein colorimetric quantification (n=3). Twenty-four 6-week-old male C57BL/6J mice were divided into PBS group, hUCMSC-sEV alone group, GelMA hydrogel alone group, and hUCMSC-sEV/GelMA hydrogel group according to the random number table, with 6 mice in each group, and after the full-thickness skin defect wounds on the back of mice in each group were produced, the wounds were performed with PBS injection, hUCMSC-sEV suspenson injection, simple GelMA coverage, and hUCMSC-sEV/GelMA hydrogel coverage, respectively. Wound healing was observed on post injury day (PID) 0 (immediately), 4, 8, and 12, and the wound healing rates on PID 4, 8, and 12 were calculated, and the wound tissue was collected on PID 12 for hematoxylin-eosin staining to observe the structure of new tissue, with sample numbers being both 6. Results: The extracted hUCMSCs-sEVs showed a cup-shaped structure and expressed CD9, CD63, and TSG101, but barely expressed calnexin. At 6, 12, and 24 h after scratching, the migration rates of HEKs (with t values of 25.94, 20.98, and 20.04, respectively), HDFs (with t values of 3.18, 5.68, and 4.28, respectively), and HUVECs (with t values of 4.32, 19.33, and 4.00, respectively) in hUCMSC-sEV group were significantly higher than those in blank control group (P<0.05). At 12 h after culture, the numbers of migrated HEKs, HDFs, and HUVECs in hUCMSC-sEV group were 550±23, 235±9, and 856±35, respectively, which were significantly higher than 188±14, 97±6, and 370±32 in blank control group (with t values of 22.95, 23.13, and 17.84, respectively, P<0.05). At 24 h after culture, the proportions of proliferating cells of HEKs, HDFs, and HUVECs in hUCMSC-sEV group were significantly higher than those in blank control group (with t values of 22.00, 13.82, and 32.32, respectively, P<0.05). The inside of simple GelMA hydrogel showed a loose and porous sponge-like structure, and hUCMSCs-sEVs was not observed in it. The hUCMSC-sEV/GelMA hydrogel had the same sponge-like structure, and hUCMSCs-sEVs were uniformly distributed in clumps. The cumulative release rate curve of hUCMSCs-sEVs from hUCMSC-sEV/GelMA hydrogel tended to plateau at 2 d after soaking, and the cumulative release rate of hUCMSCs-sEVs was (59.2±1.8)% at 12 d after soaking. From PID 0 to 12, the wound areas of mice in the 4 groups gradually decreased. On PID 4, 8, and 12, the wound healing rates of mice in hUCMSC-sEV/GelMA hydrogel group were significantly higher than those in the other 3 groups (P<0.05); the wound healing rates of mice in GelMA hydrogel alone group and hUCMSC-sEV alone group were significantly higher than those in PBS group (P<0.05). On PID 8 and 12, the wound healing rates of mice in hUCMSC-sEV alone group were significantly higher than those in GelMA hydrogel alone group (P<0.05). On PID 12, the wounds of mice in hUCMSC-sEV/GelMA hydrogel group showed the best wound epithelization, loose and orderly arrangement of dermal collagen, and the least number of inflammatory cells, while the dense arrangement of dermal collagen and varying degrees of inflammatory cell infiltration were observed in the wounds of mice in the other 3 groups. Conclusions: hUCMSCs-sEVs can promote the migration and proliferation of HEKs, HDFs, and HUVECs which are related to skin wound healing, and slowly release in GelMA hydrogel. The hUCMSC-sEV/GelMA hydrogel as a wound dressing can significantly improve the healing speed of full-thickness skin defect wounds in mice.

Effect of salvia miltiorrhiza combined with roxadustat on wound healing of full-thickness skin defects in diabetic rats and its mechanism

Effect of salvia miltiorrhiza combined with roxadustat on wound healing of full-thickness skin defects in diabetic rats and its mechanism

Analysis of the types and functions of CD34+ cells in full-thickness skin defect wounds of normal mice and diabetic mice by single-cell RNA sequencing

Objective: To analyze the types and functions of CD34+ cells in full-thickness skin defect wounds of normal mice and diabetic mice by single-cell RNA sequencing. Methods: This study was an experimental study. The CD34+ cell lineage tracing mouse was produced, and the visualization of CD34+ cells under the fluorescent condition was realized. Six male CD34+ cell lineage tracing mice aged 7-8 weeks (designated as diabetic group) were intraperitoneally injected with streptozotocin to establish a diabetic model, and full-thickness skin defect wounds were prepared on their backs when they reached 13 weeks old. Another 6 male CD34+ cell lineage tracing mice aged 13 weeks (designated as control group) were also subjected to full-thickness skin defect wounds on their backs. On post-injury day (PID) 4, wound tissue was collected from 3 mice in control group and 2 mice in diabetic group, and digested to prepare single-cell suspensions. CD34+ cells were screened using fluorescence-activated cell sorting, followed by single-cell RNA sequencing. The Seurat 4.0.2 program in the R programming language was utilized for dimensionality reduction, visualization, and cell clustering analysis of CD34+ cell types, and to screen and annotate the marker genes for each CD34+ cell subpopulation. Kyoto encyclopedia of genes and genomes (KEGG) and gene ontology (GO) enrichment analysis was performed to analyze the differentially expressed genes (DEGs) of CD34+ fibroblasts (Fbs), smooth muscle cells (SMCs), keratinocytes (KCs), and chondrocyte-like cells (CLCs) in the wound tissue of two groups of mice for exploring cellular functions. Results: On PID 4, CD34+ cells in the wound tissue of both groups of mice were consisted of 7 cell types, specifically endothelial cells, Fbs, KCs, macrophages, T cells, SMCs, and CLCs. Among these, Fbs were further classified into 5 subpopulations. Compared with those in control group, the proportions of CD34+ endothelial cells, Fbs subpopulation 1, Fbs subpopulation 4, KCs, and CLCs in the wound tissue of mice were increased in diabetic group, while the proportions of CD34+ Fbs subpopulation 2, Fbs subpopulation 3, and SMCs were decreased. The marker genes for annotating CD34+ CLCs, endothelial cells, Fbs subpopulation 1, Fbs subpopulation 2, Fbs subpopulation 3, Fbs subpopulation 4, Fbs subpopulation 5, KCs, macrophages, SMCs, and T cells were respectively metastasis-associated lung adenocarcinoma transcript 1, fatty acid binding protein 4, Gremlin 1, complement component 4B, H19 imprinted maternally expressed transcript, Dickkopf Wnt signaling pathway inhibitor 2, fibromodulin, keratin 5, CD74 molecule, regulator of G protein signaling 5, and inducible T-cell co-stimulator molecule. KEGG and GO enrichment analysis revealed that, compared with those in control group, DEGs with significant differential expression (SDE) in CD34+ Fbs from the wound tissue of mice in diabetic group on PID 4 were significantly enriched in terms related to inflammatory response, extracellular matrix (ECM) organization, regulation of cell proliferation, and aging (with Pvalues all <0.05), DEGs with SDE in CD34+ SMCs were significantly enriched in terms related to cell migration, apoptotic process, positive regulation of transcription, and phagosome (with P values all <0.05), DEGs with SDE in CD34+ KCs were significantly enriched in terms related to mitochondrial function, transcription, and neurodegenerative diseases (with P values all <0.05), and DEGs with SDE in CD34+ CLCs were significantly enriched in terms related to rhythm regulation, ECM, and viral infection (with P values all <0.05). Conclusions: CD34+ cells display high heterogeneity in the healing process of full-thickness skin defect wounds in both normal mice and diabetic mice. The significantly enriched functions of DEGs with SDE in CD34+ cell subpopulations in the wound tissue of the two mouse groups are closely related to the wound healing process.

Effects of cerium oxide nanoenzyme-gelatin methacrylate anhydride hydrogel in the repair of infected full-thickness skin defect wounds in mice

Objective: To investigate the effects of cerium oxide nanoenzyme-gelatin methacrylate anhydride (GelMA) hydrogel (hereinafter referred to as composite hydrogel) in the repair of infected full-thickness skin defect wounds in mice. Methods: This study was an experimental study. Cerium oxide nanoenzyme with a particle size of (116±9) nm was prepared by hydrothermal method, and GelMA hydrogel with porous network structure and good gelling performance was also prepared. The 25 μg/mL cerium oxide nanoenzyme which could significantly promote the proliferation of human skin fibroblasts and had high superoxide dismutase activity was screened out. It was added to GelMA hydrogel to prepare composite hydrogel. The percentage of cerium oxide nanoenzyme released from the composite hydrogel was calculated after immersing it in phosphate buffer solution (PBS) for 3 and 7 d. The red blood cell suspension of mice was divided into PBS group, Triton X-100 group, cerium oxide nanoenzyme group, GelMA hydrogel group, and composite hydrogel group, which were treated with corresponding solution. The hemolysis of red blood cells was detected by microplate reader after 1 h of treatment. The bacterial concentrations of methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli were determined after being cultured with PBS, cerium oxide nanoenzyme, GelMA hydrogel, and composite hydrogel for 2 h. The sample size in all above experiments was 3. Twenty-four 8-week-old male BALB/c mice were taken, and a full-thickness skin defect wound was prepared in the symmetrical position on the back and infected with MRSA. The mice were divided into control group without any drug intervention, and cerium oxide nanoenzyme group, GelMA hydrogel group, and composite hydrogel group applied with corresponding solution, with 6 mice in each group. The wound healing was observed on 3, 7, and 14 d after injury, and the remaining wound areas on 3 and 7 d after injury were measured (the sample size was 5). The concentration of MRSA in the wound exudation of mice on 3 d after injury was measured (the sample size was 3), and the blood flow perfusion in the wound of mice on 5 d after injury was observed using a laser speckle flow imaging system (the sample size was 6). On 14 d after injury, the wound tissue of mice was collected for hematoxylin-eosin staining to observe the newly formed epithelium and for Masson staining to observe the collagen situation (the sample size was both 3). Results: After immersion for 3 and 7 d, the release percentages of cerium oxide nanoenzyme in the composite hydrogel were about 39% and 75%, respectively. After 1 h of treatment, compared with that in Triton X-100 group, the hemolysis of red blood cells in PBS group, GelMA hydrogel group, cerium oxide nanoenzyme group, and composite hydrogel group was significantly decreased (P<0.05). Compared with that cultured with PBS, the concentrations of MRSA and Escherichia coli cultured with cerium oxide nanoenzyme, GelMA hydrogel, and composite hydrogel for 2 h were significantly decreased (P<0.05). The wounds of mice in the four groups were gradually healed from 3 to 14 d after injury, and the wounds of mice in composite hydrogel group were all healed on 14 d after injury. On 3 and 7 d after injury, the remaining wound areas of mice in composite hydrogel group were (29±3) and (13±5) mm2, respectively, which were significantly smaller than (56±12) and (46±10) mm2 in control group and (51±7) and (38±8) mm2 in cerium oxide nanoenzyme group (with P values all <0.05), but was similar to (41±5) and (24±9) mm2 in GelMA hydrogel group (with P values both >0.05). On 3 d after injury, the concentration of MRSA on the wound of mice in composite hydrogel group was significantly lower than that in control group, cerium oxide nanoenzyme group, and GelMA hydrogel group, respectively (with P values all <0.05). On 5 d after injury, the volume of blood perfusion in the wound of mice in composite hydrogel group was significantly higher than that in control group, cerium oxide nanoenzyme group, and GelMA hydrogel group, respectively (P<0.05). On 14 d after injury, the wound of mice in composite hydrogel group basically completed epithelization, and the epithelization was significantly better than that in the other three groups. Compared with that in the other three groups, the content of collagen in the wound of mice in composite hydrogel group was significantly increased, and the arrangement was also more orderly. Conclusions: The composite hydrogel has good biocompatibility and antibacterial effect in vivo and in vitro. It can continuously sustained release cerium oxide nanoenzyme, improve wound blood perfusion in the early stage, and promote wound re-epithelialization and collagen synthesis, therefore promoting the healing of infected full-thickness skin defect wounds in mice.

Slow-sculpting graphene oxide/alginate gel loaded with platelet-rich plasma to promote wound healing in rats.

Wounds, especially chronic wounds, have become an important problem that endangers human health. At present, there are many repair methods, and among them combines materials science and biology is one of the important repair methods. This study explored the preparation method, physicochemical properties, biological activity and safety of Platelet-Rich plasma (PRP)-loaded slow-sculpting graphene oxide (GO)/alginate gel, and applied it to acute full-thickness skin defect wounds in rats to observe its role in wound healing. The results show that the slow-sculpting GO/alginate gel has excellent plasticity and is suitable for a variety of irregularly shaped wounds. At the same time, its porous structure and water content can maintain the activity of platelets and their released growth factors in PRP, thereby promoting wound collagen synthesis and angiogenesis to accelerate wound healing. This indicates that the slow-sculpting GO/alginate gel is an excellent loading material for PRP, and the combination of the two may become one of the methods to promote wound repair.

Properties of gelatin-polyethylene glycol hydrogel loaded with silver nanoparticle Chlorella and its effects on healing of infected full-thickness skin defect wounds in mice

Properties of gelatin-polyethylene glycol hydrogel loaded with silver nanoparticle Chlorella and its effects on healing of infected full-thickness skin defect wounds in mice

Preparation of chitin/hyaluronic acid/collagen hydrogel loaded with mouse adipose-derived stem cells and its effects on wound healing of full-thickness skin defects in rats

Objective: To prepare the chitin/hyaluronic acid/collagen hydrogel loaded with mouse adipose-derived stem cells and to explore its effects on wound healing of full-thickness skin defects in rats. Methods: The research was an experimental research. Chitin nanofibers were prepared by acid hydrolysis and alkaline extraction method, and then mixed with hyaluronic acid and collagen to prepare chitin/hyaluronic acid/collagen hydrogels (hereinafter referred to as hydrogels). Besides, the hydrogels loaded with mouse adipose-derived stem cells were prepared. Thirty male 12-week-old guinea pigs were divided into negative control group, positive control group, and hydrogel group according to the random number table, with 10 guinea pigs in each group. Ethanol, 4-aminobenzoic acid ethyl ester, or the aforementioned prepared hydrogels without cells were topically applied on both sides of back of guinea pigs respectively for induced contact and stimulated contact, and skin edema and erythema formation were observed at 24 and 48 h after stimulated contact. Adipose-derived stem cells from mice were divided into normal control group cultured routinely and hydrogel group cultured with the aforementioned prepared hydrogels without cells. After 3 d of culture, protein expressions of platelet-derived growth factor-D (PDGF-D), insulin-like growth factor-Ⅰ (IGF-Ⅰ), and transforming growth factor β1 (TGF-β1) were detected by Western blotting (n=3). Eight male 8-week-old Sprague-Dawley rats were taken and a circular full-thickness skin defect wound was created on each side of the back. The wounds were divided into blank control group without any treatment and hydrogel group with the aforementioned prepared hydrogels loaded with adipose-derived stem cells applied. Wound healing was observed at 0 (immediately), 2, 4, 8, and 10 d after injury, and the wound healing rate was calculated at 2, 4, 8, and 10 d after injury. Wound tissue samples at 10 d after injury were collected, the new tissue formation was observed by hematoxylin-eosin staining; the concentrations of interleukin-1α (IL-1α), IL-6, IL-4, and IL-10 were detected by enzyme-linked immunosorbent assay method; the expressions of CD16 and CD206 positive cells were observed by immunohistochemical staining and the percentages of positive cells were calculated. The sample numbers in animal experiment were all 8. Results: At 24 h after stimulated contact, no skin edema was observed in the three groups of guinea pigs, and only mild skin erythema was observed in 7 guinea pigs in positive control group. At 48 h after stimulated contact, skin erythema was observed in 8 guinea pigs and skin edema was observed in 4 guinea pigs in positive control group, while no obvious skin erythema or edema was observed in guinea pigs in the other two groups. After 3 d of culture, the protein expression levels of PDGF-D, IGF-I, and TGF-β1 in adipose-derived stem cells in hydrogel group were significantly higher than those in normal control group (with t values of 12.91, 11.83, and 7.92, respectively, P<0.05). From 0 to 10 d after injury, the wound areas in both groups gradually decreased, and the wounds in hydrogel group were almost completely healed at 10 d after injury. At 4, 8, and 10 d after injury, the wound healing rates in hydrogel group were (38±4)%, (54±5)%, and (69±6)%, respectively, which were significantly higher than (21±6)%, (29±7)%, and (31±7)% in blank control group (with t values of 3.82, 3.97, and 4.05, respectively, Pvalues all <0.05). At 10 d after injury, compared with those in blank control group, the epidermis in wound in hydrogel group was more intact, and there were increases in hair follicles, blood vessels, and other skin appendages. At 10 d after injury, the concentrations of IL-1α and IL-6 in wound tissue in hydrogel group were significantly lower than those in blank control group (with tvalues of 8.21 and 7.99, respectively, P<0.05), while the concentrations of IL-4 and IL-10 were significantly higher than those in blank control group (with tvalues of 6.57 and 9.03, respectively, P<0.05). The percentage of CD16 positive cells in wound tissue in hydrogel group was significantly lower than that in blank control group (t=8.02, P<0.05), while the percentage of CD206 positive cells was significantly higher than that in blank control group (t=7.21, P<0.05). Conclusions: The hydrogel loaded with mouse adipose-derived stem cells is non-allergenic, can promote the secretion of growth factors in adipose-derived stem cells, promote the polarization of macrophages to M2 phenotype in wound tissue in rats with full-thickness skin defects, and alleviate inflammatory reaction, thereby promoting wound healing.

A TA/Cu2+ Nanoparticle Enhanced Carboxymethyl Chitosan-Based Hydrogel Dressing with Antioxidant Properties and Promoting Wound Healing.

As the first line of immune defense and the largest organ of body, skin is vulnerable to damage caused by surgery, burns, collisions and other factors. Wound healing in the skin is a long and complex physiological process that is influenced by a number of different factors. Proper wound care can greatly improve the speed of wound healing and reduce the generation of scars. However, traditional wound dressings (bandages, gauze, etc.) often used in clinical practice have a single function, lack of active ingredients and are limited in use. Hydrogels with three-dimensional network structure are a potential biomedical material because of their physical and chemical environment similar to extracellular matrix. In particular, hydrogel dressings with low price, good biocompatibility, degradability, antibacterial and angiogenic activity are favored by the public. Here, a carboxymethyl chitosan-based hydrogel dressing (CMCS-TA/Cu2+) reinforced by copper ion crosslinked tannic acid (TA/Cu2+) nanoparticles was developed. This study investigated the physical and chemical characteristics, cytotoxicity, and angiogenesis of TA/Cu2+ nanoparticles and CMCS-TA/Cu2+ hydrogels. Furthermore, a full-thickness skin defect wound model was employed to assess the in vivo wound healing capacity of hydrogel dressings. The introduction of TA/Cu2+ nanoparticles not only could increase the mechanical properties of the hydrogel but also continuously releases copper ions to promote cell migration (the cell migration could reach 92% at 48 h) and tubule formation, remove free radicals and promote wound healing (repair rate could reach 90% at 9 days). Experiments have proved that CMCS-TA/Cu2+ hydrogel has good cytocompatibility, antioxidant and wound healing ability, providing an advantageous solution for skin repair.

A tilapia skin-derived gelatin hydrogel combined with the adipose-derived stromal vascular fraction for full-thickness wound healing.

Biomaterials are widely used in regenerative medicine to repair full-thickness skin defect wounds. The adipose-derived stromal vascular fraction (SVF) shows pro-regenerative properties, however, the ex vivo biological activity of SVF is suppressed due to the lack of an external scaffold. Tilapia skin, as a sustained and recyclable biomaterial with low immunogenicity, was applied in the preparation of a hydrogel. The mixture of tilapia skin-derived gelatin and methacrylic anhydride as a scaffold facilitated the paracrine function of SVF and exerted a synergistic effect with SVF to promote wound healing. In this study, 30% (w/v) SVF was added to methacrylate-functionalized tilapia skin gelatin and subsequently exposed to UV irradiation to form a three-dimensional nano-scaffolding composite hydrogel (FG-SVF-3). The effects of paracrine growth factors, neovascularization, and collagen production on wound healing were extensively discussed. FG-SVF-3 displayed a pronounced wound healing ability via in vivo wound models. The FG-SVF-3 hydrogel enhanced the biocompatibility and the expression of EGF, bFGF, and VEGF. FG-SVF-3, as a promising wound dressing, exhibited superior ability to accelerate wound healing, skin regeneration, and wound closure.

A photothermally antibacterial Au@Halloysite nanotubes/lignin composite hydrogel for promoting wound healing

The construction of an effective antibacterial micro-environment to prevent infection and biofilm formation is critically important for the design of wound dressings. Herein, a novel hydrogel wound dressing was fabricated by embedding Au nanoparticles-decorated halloysite nanotubes (Au@HNTs) into the lignin-based hydrogel matrix containing polyvinyl alcohol and chitosan. The resulting composite hydrogel, noted as LPC-Au@HNTs, exhibited an excellent photothermal antibacterial activity owing to the embedded Au@HNTs in which Au nanoparticles were generously filled into the lumen of Halloysite nanotubes. The typical sample containing 4 wt% of Au@HNTs in the composite hydrogel (LPC-Au@HNTs4) had good mechanical and photothermal properties. The surface temperature of as-prepared hydrogel increased to 57.59 °C after 5 min upon NIR light irradiation (808 nm) at 1.0 W/cm2. The photothermal effect endowed the hydrogel dressing with excellent antibacterial activity, with significantly enhanced inhibition rates of Escherichia coli (99.00 %) and Staphylococcus aureus (98.88 %). Experiments in a mouse full-thickness skin defect wound model also showed that the hydrogel dressing had a facilitative effect on the repair of traumatic surfaces. This study provides a broadly appliable wound dressing for treating bacteria-infected wounds, greatly contributing to the design of photothermal antibacterial biomedical materials for wound healing.

Injectable Antiswelling and High-Strength Bioactive Hydrogels with a Wet Adhesion and Rapid Gelling Process to Promote Sutureless Wound Closure and Scar-free Repair of Infectious Wounds.

Developing injectable antiswelling and high-strength bioactive hydrogels with wet tissue adhesiveness and a rapid gelling process to meet the requirements for rapid hemostasis, sutureless wound closure, and scar-free repair of infected skin wounds continues to have ongoing challenges. Herein, injectable, antibacterial, and antioxidant hydrogel adhesives based on poly(citric acid-co-polyethylene glycol)-g-dopamine and amino-terminated Pluronic F127 (APF) micelles loaded with astragaloside IV (AS) are prepared. The H2O2/horseradish peroxidase (HRP) system is used to cause cross-linking of the hydrogel network through oxidative coupling between catechol groups and chemical cross-linking between the catechol group and the amino group. The hydrogels exhibit a rapid gelling process, high mechanical strength, an antiswelling effect, good antioxidant property, H2O2 release behavior, and degradability. In addition, the hydrogels present good wet tissue adhesiveness, high bursting pressure, excellent antibacterial activity, long-term sustained release of AS, and good biocompatibility. The hydrogels perform good hemostasis on mouse liver, rat liver, and rabbit femoral vein bleeding models and achieve much better closure and healing of skin incisions than biomedical glue and surgical sutures. Furthermore, the hydrogel dressing significantly improved the scar-free repair of MRSA-infected full thickness skin defect wounds by modulating inflammation, regulating the ratio of collagen I/III, and improving the vascularization and granulation tissue formation. Thus, AS-loaded hydrogels show huge potential as multifunctional dressings for in vivo hemostasis, sutureless wound closure, and scar-free repair of infected skin wounds.

CeAF Ameliorates Diabetic Wound Healing by Alleviating Inflammation and Oxidative Stress via TLR4/NF-κB and Nrf2 Pathways.

With the rise in diabetes incidence, diabetic foot ulcers have become the most common clinically chronic refractory wounds. Persistent chronic inflammation is a typical feature of diabetic cutaneous wounds, and diabetic wound healing can be improved by alleviating inflammation and oxidative stress. Chick early amniotic fluids (ceAF) consist of native conglutinant substances with balanced amounts of growth factors, cytokines, and chemokines. However, whether ceAF modulates inflammation and oxidative stress and thus promotes diabetic wound healing remains unknown. RAW264.7 cells were categorized into four groups: negative control, LPS, LPS + ceAF, and ceAF. 10% of ceAF was selected to treat different groups of mice with a full-thickness skin defect wound. Then, RT-qPCR, western blot, immunofluorescence, and other assays were carried out to explore the effect of ceAF on wound healing and its molecular mechanism. Topical administration of ceAF improved M2 macrophage polarization and inflammatory response in the wound tissues, thereby ameliorating delayed wound healing. Histological improvement could be observed in the grade of inflammation, collagen deposition, and neovascularization in wound edge tissues. ceAF also increased M2 macrophage-specific markers expression and exogenous ceAF suppressed LPS-induced cellular inflammatory response in vitro high glucose environment. Additionally, ceAF could activate TLR4/NF-κB and Nrf2 signal transductions to promote M2 macrophage polarization in vitro. In summary, ceAF downregulates inflammatory response, regulates M2 macrophage transition via TLR4/NF-κB and Nrf2 signaling pathways, and thus improves diabetic wound healing.

Influence of autologous adipose stem cell matrix gel on wound healing and scar hyperplasia of full-thickness skin defects in rabbit ears

Influence of autologous adipose stem cell matrix gel on wound healing and scar hyperplasia of full-thickness skin defects in rabbit ears

Effects of tumor necrosis factor-alpha/extracellular signal-regulated kinase pathway on migration ability of HaCaT cells and full-thickness skin defects in mice

Effects of tumor necrosis factor-alpha/extracellular signal-regulated kinase pathway on migration ability of HaCaT cells and full-thickness skin defects in mice

Heparin-based sericin hydrogel–encapsulated basic fibroblast growth factor for in vitro and in vivo skin repair

The treatment of full-thickness cutaneous wounds remains a significant challenge in clinical therapeutics. Exogenous growth factor (GF) has been applied in clinics to promote wound healing. However, the retention of GF on the wound bed after its direct application to the wound surface is difficult. Moreover, growth factors (GFs) are always inactivated in the complex wound healing microenvironment due to various factors, which significantly decrease the therapeutic effect. Sericin hydrogel (S) can be used as an effective carrier for GFs owing to its low immunogenicity, good biocompatibility, and good healing-promoting ability. Here, we designed a heparin-based sericin hydrogel (HS) -encapsulated basic fibroblast growth factor (bFGF-HS) to facilitate wound healing and skin regeneration. The hydrogel exhibited a three-dimensional (3D) microporous structure, excellent biodegradability, good adhesiveness, and low cytotoxicity. In vitro release of bFGF from bFGF-HS coacervates revealed that bFGF-HS might control the release of bFGF within 25 days through heparin regulation. bFGF-HS significantly promoted vascularization and re-epithelialization and improved collagen deposition, ultimately accelerating wound healing in vivo in mice. bFGF-HS treated wounds were also found to have more hair follicles and milder inflammatory reactions. Overall, this study provides a new therapeutic approach for full-thickness skin defect wounds using bFGF-HS.

Effects of interleukin-4-modified gold nanozymes on the full-thickness skin defects in diabetic mice

Effects of interleukin-4-modified gold nanozymes on the full-thickness skin defects in diabetic mice