Later Stages Of Wound Healing Research Articles

Skin organoid transplantation promotes tissue repair with scarless in frostbite.

Frostbite is the most common cold injury and is caused by both immediate cold-induced cell death and the gradual development of localized inflammation and tissue ischemia. Delayed healing of frostbite often leads to scar formation, which not only causes psychological distress but also tends to result in the development of secondary malignant tumors. Therefore, a rapid healing method for frostbite wounds is urgently needed. Herein, we used a mouse skin model of frostbite injury to evaluate the recovery process after frostbite. Moreover, single-cell transcriptomics was used to determine the patterns of changes in monocytes, macrophages, epidermal cells and fibroblasts during frostbite. Most importantly, human-induced pluripotent stem cell (hiPSC) -derived skin organoids combining with gelatin-hydrogel were constructed for the treatment of frostbite. The results showed that skin organoid treatment significantly accelerated wound healing by reducing early inflammation after frostbite and increasing the proportions of epidermal stem cells. Moreover, in the later stage of wound healing, skin organoids reduced the overall proportions of fibroblasts, significantly reduced fibroblast-to-myofibroblast transition by regulating the integrin α5β1-FAK pathway, and remodeled the extracellular matrix (ECM) through degradation and reassembly mechanisms, facilitating the restoration of physiological ECM and reducing the abundance of ECM associated with abnormal scar formation. These results highlight the potential application of organoids for promoting the reversal of frostbite-related injury and the recovery of skin functions. This study provides a new therapeutic alternative for patients suffering from disfigurement and skin dysfunction caused by frostbite.

Taurine and Polyphenol Complex Repaired Epidermal Keratinocyte Wounds by Regulating IL8 and TIMP2 Expression.

The healing process after acne lesion extraction provides a miniature model to study skin wound repair mechanisms. In this study, we aimed to identify solutions for acne scars that frequently occur on our faces. We performed acne scar cytokine profiling and found that Interleukin 8 (IL8) and Tissue inhibitor of metalloproteinases 2 (TIMP2) were significant factors at the wounded site. The effect of chlorogenic acid and taurine on human epidermal cells and irritated human skin was investigated. Chlorogenic acid and taurine regulated IL8 and TIMP2 expression and accelerated keratinocyte proliferation. Moreover, tight junction protein expression was upregulated by chlorogenic acid and taurine synergistically. Further, these compounds modulated the expression of several inflammatory cytokines (IL1α, IL1β, and IL6) and skin hydration related factor (hyaluronan synthase 3; HAS3). Thus, chlorogenic acid and taurine may exert their effects during the late stages of wound healing rather than the initial phase. In vivo experiments using SLS-induced wounds demonstrated the efficacy of chlorogenic acid and taurine treatment compared to natural healing, reduced erythema, and restored barrier function. Skin ultrasound analysis revealed their potential to promote denser skin recovery. Therefore, the wound-restoring effect of chlorogenic acid and taurine was exerted by suppression of inflammatory cytokines, and induction of cell proliferation, tight junction expression, and remodeling factors.

Integrating Bioactive Graded Hydrogel with Radially Aligned Nanofibers to Dynamically Manipulate Wound Healing Process.

Skin wound healing is a complex process that requires appropriate treatment and management. Using a single scaffold to dynamically manipulate angiogenesis, cell migration and proliferation, and tissue reconstruction during skin wound healing is a great challenge. We developed a hybrid scaffold platform that integrates the spatiotemporal delivery of bioactive cues with topographical cues to dynamically manipulate the wound-healing process. The scaffold comprised gelatin methacryloyl hydrogels and electrospun poly(ε-caprolactone)/gelatin nanofibers. The hydrogels had graded cross-linking densities and were loaded with two different functional bioactive peptides. The nanofibers comprised a radially aligned nanofiber array layer and a layer of random fibers. During the early stages of wound healing, the KLTWQELYQLKYKGI peptide, which mimics vascular endothelial growth factor, was released from the inner layer of the hydrogel to accelerate angiogenesis. During the later stages of wound healing, the IKVAVS peptide, which promotes cell migration, synergized with the radially aligned nanofiber membrane to promote cell migration, while the nanofiber membrane also supported further cell proliferation. In an in vivo rat skin wound-healing model, the hybrid scaffold significantly accelerated wound healing and collagen deposition, and the ratio of type I to type III collagen at the wound site resembled that of normal skin. The prepared scaffold dynamically regulated the skin tissue regeneration process in stages to achieve rapid wound repair with clinical application potential, providing a strategy for skin wound repair.

A Rheological Study on the Effect of Tethering Pro- and Anti-Inflammatory Cytokines into Hydrogels on Human Mesenchymal Stem Cell Migration, Degradation, and Morphology.

Polymer-peptide hydrogels are being designed as implantable materials that deliver human mesenchymal stem cells (hMSCs) to treat wounds. Most wounds can progress through the healing process without intervention. During the normal healing process, cytokines are released from the wound to create a concentration gradient, which causes directed cell migration from the native niche to the wound site. Our work takes inspiration from this process and uniformly tethers cytokines into the scaffold to measure changes in cell-mediated degradation and motility. This is the first step in designing cytokine concentration gradients into the material to direct cell migration. We measure changes in rheological properties, encapsulated cell-mediated pericellular degradation and migration in a hydrogel scaffold with covalently tethered cytokines, either tumor necrosis factor-α (TNF-α) or transforming growth factor-β (TGF-β). TNF-α is expressed in early stages of wound healing causing an inflammatory response. TGF-β is released in later stages of wound healing causing an anti-inflammatory response in the surrounding tissue. Both cytokines cause directed cell migration. We measure no statistically significant difference in modulus or the critical relaxation exponent when tethering either cytokine in the polymeric network without encapsulated hMSCs. This indicates that the scaffold structure and rheology is unchanged by the addition of tethered cytokines. Increases in hMSC motility, morphology and cell-mediated degradation are measured using a combination of multiple particle tracking microrheology (MPT) and live-cell imaging in hydrogels with tethered cytokines. We measure that tethering TNF-α into the hydrogel increases cellular remodeling on earlier days postencapsulation and tethering TGF-β into the scaffold increases cellular remodeling on later days. We measure tethering either TGF-β or TNF-α enhances cell stretching and, subsequently, migration. This work provides rheological characterization that can be used to design new materials that present chemical cues in the pericellular region to direct cell migration.

Development of alginate and alginate sulfate/polycaprolactone nanoparticles for growth factor delivery in wound healing therapy

Connective tissue growth factor (CTGF) holds great promise for enhancing the wound healing process; however, its clinical application is hindered by its low stability and the challenge of maintaining its effective concentration at the wound site. Herein, we developed novel double-emulsion alginate (Alg) and heparin-mimetic alginate sulfate (AlgSulf)/polycaprolactone (PCL) nanoparticles (NPs) for controlled CTGF delivery to promote accelerated wound healing. The NPs’ physicochemical properties, cytocompatibility, and wound healing activity were assessed on immortalized human keratinocytes (HaCaT), primary human dermal fibroblasts (HDF), and a murine cutaneous wound model. The synthesized NPs had a minimum hydrodynamic size of 200.25 nm. Treatment of HaCaT and HDF cells with Alg and AlgSulf2.0/PCL NPs did not show any toxicity when used at concentrations <50 µg/mL for up to 72 h. Moreover, the NPs’ size was not affected by elevated temperatures, acidic pH, or the presence of a protein-rich medium. The NPs have slow lysozyme-mediated degradation implying that they have an extended tissue retention time. Furthermore, we found that treatment of HaCaT and HDF cells with CTGF-loaded Alg and AlgSulf2.0/PCL NPs, respectively, induced rapid cell migration (76.12% and 79.49%, P<0.05). Finally, in vivo studies showed that CTGF-loaded Alg and AlgSulf2.0/PCL NPs result in the fastest and highest wound closure at the early and late stages of wound healing, respectively (36.49%, P<0.001 on day 1; 90.45%, P<0.05 on day 10), outperforming free CTGF. Double-emulsion NPs based on Alg or AlgSulf represent a viable strategy for delivering heparin-binding GF and other therapeutics, potentially aiding various disease treatments.

Low-temperature plasma jet suppresses bacterial colonisation and affects wound healing through reactive species.

An argon-based low-temperature plasma jet (LTPJ) was used to treat chronically infected wounds in Staphylococcus aureus-laden mice. Based on physicochemical property analysis and in vitro antibacterial experiments, the effects of plasma parameters on the reactive nitrogen and oxygen species (RNOS) content and antibacterial capacity were determined, and the optimal treatment parameters were determined to be 4 standard litre per minute and 35 W. Additionally, the plasma-treated activation solution had a bactericidal effect. Although RNOS are related to the antimicrobial effect of plasma, excess RNOS may be detrimental to wound remodelling. In vivo studies demonstrated that medium-dose LTPJ promoted MMP-9 expression and inhibited bacterial growth during the early stages of healing. Moreover, LTPJ increased collagen deposition, reduced inflammation, and restored blood vessel density and TGF-β levels to normal in the later stages of wound healing. Therefore, when treating chronically infected wounds with LTPJ, selecting the medium dose of plasma is more advantageous for wound recovery. Overall, our study demonstrated that low-temperature plasma jets may be a potential tool for the treatment of chronically infected wounds.

A Preliminary Study on Quantitative Analysis of Collagen and Apoptosis Related Protein on 1064 nm Laser-Induced Skin Injury.

To investigate the associated factors concerning collagen and the expression of apoptosis-related proteins in porcine skin injuries induced by laser exposure, live pig skin was irradiated at multiple spots one time, using a grid-array method with a 1064 nm laser at different power outputs. The healing process of the laser-treated areas, alterations in collagen structure, and changes in apoptosis were continuously observed and analyzed from 6 h to 28 days post-irradiation. On the 28th day following exposure, wound contraction and recovery were notably sluggish in the medium-high dose group, displaying more premature and delicate type III collagen within the newly regenerated tissues. The collagen density in these groups was roughly 37-58% of that in the normal group. Between days 14 and 28 after irradiation, there was a substantial rise in apoptotic cell count in the forming epidermis and granulation tissue of the medium-high dose group, in contrast to the normal group. Notably, the expression of proapoptotic proteins Bax, caspase-3, and caspase-9 surged significantly 14 days after irradiation in the medium-high dose group and persisted at elevated levels on the 28th day. During the later stage of wound healing, augmented apoptotic cell population and insufficient collagen generation in the newly generated skin tissue of the medium-high dose group were closely associated with delayed wound recovery.

H2S donor S-propargyl-cysteine for skin wound healing improvement via smart transdermal delivery.

Hydrogen sulfide for wound healing has drawn a lot of attention recently. In this research, the S-propargyl-cysteine (SPRC), an endogenous H2S donor, was loaded on carbomerhydrogel, and a copper sheet rat burn model was developed. Pathological changes in rat skin tissue were examined using hematoxylin-eosin (HE) and Masson staining. The immunohistochemistry (IHC) staining was performed to detect the expression of Collagen I (Col I) and Collagen III (Col III). The mRNA levels of interleukin (IL)-6, Col Iα2, Col IIIα1, tissue inhibitors of metalloproteinase (TIMP)-1, matrix metalloproteinase (MMP)-9, vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)-β1 were examined by quantitative real-time chain polymerase reaction. The findings demonstrated that the collagen layer was thicker in the SPRC group during the proliferative phase, SPRC hydrogel promoted VEGF expression. In the late stage of wound healing, the expression of IL-6, TIMP-1, MMP-9, and TGF-β1 was inhibited, and the Col I content was closer to that of normal tissue. These results surface that SPRC hydrogel can promote wound healing and play a positive role in reducing scar formation. Our results imply that SPRC can facilitate wound healing and play a positive role in reducing scar formation.

Polymyxin B-targeted liposomal photosensitizer cures MDR A. baumannii burn infections and accelerates wound healing via M1/M2 macrophage polarization

Multidrug-resistant (MDR) Acinetobacter baumannii infections pose a significant challenge in burn wound management, necessitating the development of innovative therapeutic strategies. In this work, we introduced a novel polymyxin B (PMB)-targeted liposomal photosensitizer, HMME@Lipo-PMB, for precise and potent antimicrobial photodynamic therapy (aPDT) against burn infections induced by MDR A. baumanni. HMME@Lipo-PMB-mediated aPDT exhibited enhanced antibacterial efficacy by specifically targeting and disrupting bacterial cell membranes, and generating increased intracellular ROS. Remarkably, even at low concentrations, this targeted approach significantly reduced bacterial viability in vitro and completely eradicated burn infections induced by MDR A. baumannii in vivo. Additionally, HMME@Lipo-PMB-mediated aPDT facilitated burn infection wound healing by modulating M1/M2 macrophage polarization. It also effectively promoted acute inflammation in the early stage, while attenuated chronic inflammation in the later stage of wound healing. This dynamic modulation promoted the formation of granulation tissue, angiogenesis, and collagen regeneration. These findings demonstrate the tremendous potential of HMME@Lipo-PMB-mediated aPDT as a promising alternative for the treatment of burn infections caused by MDR A. baumannii.

Double-Layer Hydrogel with Glucose-Activated Two-Stage ROS Regulating Properties for Programmed Diabetic Wound Healing.

Slow healing of wounds induces great pain in diabetic patients. However, developing new approaches to promote diabetic wound healing is still one of the toughest challenges in the medical field. Here, we constructed a new double-layer hydrogel to effectively regulate reactive oxygen species (ROS) on the wound and promote diabetic wound healing. The inner layer contains glucose oxidase (Gox), ferrocene-modified quaternary ammonium chitosan (Fc-QCs), and poly(β-cyclodextrin) (Pβ-CD), which is used to generate hydroxyl radicals (•OH) for antibacterial in the early stage of wound healing and collapses gradually. The outer layer is composed of gelatin and dopamine. In the later stage of wound healing, the outer layer contacts the skin, which is beneficial for ROS clearance on the wound. Antibacterial, ROS scavenging, and wound healing experiments have shown that the double-layer hydrogel possesses two-stage ROS regulating properties for programmed diabetic wound healing. In conclusion, it will be one of the most potential dressings for treating diabetic wounds in the future.

A mechanistic insight into cytokines and growth factors in saudi pomegranate peel extract (Punica granatum L.) mediated diabetic wound healing in alloxan induced diabetic rats

IntroductionPresent study was designed to understand the role of inflammatory markers and growth factors in later stage of wound healing after treatment with SPPE on wound in alloxan induced diabetic rats. MethodologyThe study was performed by inducing diabetes in wistar rats using alloxan at 150 mg/kg, subcutaneously. The animals were allocated in three groups: Group 1- diabetic excision wound (DEW) without any treatment, Group 2- DEW treated with gel vehicle only, Group 3- DEW treated with 5 %SPPE containing gel. During the treatment period of twenty-one days animals were monitored based on clinical signs, morbidity, and mortality. Percent wound contraction, Growth factors (VEGF, and EGF), proinflammatory markers TNF- α, IL-1β, MCP-1, IL-4, and IL-17a, anti-inflammatory marker IL-10 in wound lysates, and histology of skin were all considered as indicators of effectiveness. ResultsThe vehicle control when compared with the SPPE in gel (5.0 g extract per 100 g of gel) presented significant [p < 0.001] wound healing activity at day 14 and 21 of treatment. Throughout the treatment period the animals were normal and showed no comparable difference in terms of body weight both in group 1 and treatment groups. Both growth factors VEGF & EGF levels were significantly increased in SPPE gel treated wounds on day 14 and 21 compared to Group 2. Other inflammatory markers like TNF- α, IL-1 β and IL-17a were also significantly decreased in SPPE treated wounds as compared to other groups. ConclusionsThis study concludes that topical application of SPPE gel to alloxan-induced diabetic wounds decreases pro-inflammation markers and increases growth factors, hence promoting wound healing.

Incorporating copper-based nanosheets into an injectable self-healing hydrogel enables superb repair of infected diabetic wound

Continuous bleeding, bacterial infection, oxidative stress, and vascular damage within a diabetic wound microenvironment necessitate the development of multifunctional dressings that match the complex physiological process of skin healing. Herein, copper–tannic acid (CuTA) nanosheets were first synthesized by chelating copper ions with tannic acid (TA). These nanosheets were subsequently integrated into an injectable self-healing hydrogel comprising methacrylic anhydride-modified gelatin (GelMA), cationic guar gum (CG), and borax. Through free-radical polymerization as well as hydrogen and borate ester bonds formation, we fabricated an acidic and highly reactive oxygen species (ROS)-responsive composite hydrogel named GGB-CT, which exhibited remarkable hemostasis and adhesion. With responsive decomposition of GGB-CT, the released CuTA efficiently scavenged excess ROS as well as effectively killed bacteria by inhibiting arginine synthesis, blocking the tricarboxylic acid cycle and inducing cuproptosis-like death in the tested microbes. In the later stages of wound healing, the composite hydrogel substantially promoted macrophage polarization and angiogenesis, thus accelerating the re-epithelialization of the wound area. Overall, this study proposes an innovative hydrogel for treating infected diabetic wounds and may inspire new thinking of high-performance hydrogels for biomedical applications.

A novel multifunctional chitosan-gelatin/carboxymethyl cellulose-alginate bilayer hydrogel containing human placenta extract for accelerating full-thickness wound healing

The replication of skin's dermal and epidermal morphology within a full-thickness wound using a bi-layer hydrogel to cater to their distinct needs is a compelling pursuit. Moreover, human placenta extract (HPE), containing a diverse array of bioactive agents, has proven to be effective in promoting the wound healing process and enhancing epidermal keratinocytes. This study presents a multifunctional bi-layer hydrogel incorporating HPE for accelerating full-thickness wound healing through sustained HPE release, inhibition of bacteria invasion, and promotion of cell proliferation. The upper layer of the scaffold, known as the dressing layer, is composed of carboxymethyl cellulose and sodium alginate, serving as a supportive layer for cell proliferation. The under layer, referred to as the regenerative layer, is composed of chitosan and gelatin, providing an extracellular matrix-like, porous, moist, and antibacterial environment for cell growth. The scaffold was optimized to replicate the morphology of the dermal and epidermal layers, with suitable fibroblast infiltration and a pore size of approximately 283μm. Furthermore, the degradation rate of the samples matched the wound healing rate and persisted throughout this period. The sustained HPE release rate, facilitated by the degradation rate, was optimized to reach ~98% after 28 days, covering the entire healing period. The samples demonstrated robust antibacterial capabilities, with bacterial inhibition zone diameters of2.56±0.10cm and 2.63±0.12cm for S. aureus and E. coli, respectively. The biocompatibility of the samples remained at approximately 68.33±4.5% after 21 days of fibroblast cell culture. The in vivo experiment indicated that the HPE@Bilayer hydrogel promotes the formation of new blood vessels and fibroblasts during the early stages of healing, leading to the appropriate formation of granulation tissue and a wound contraction rate of (79.31±3.1)%. Additionally, it resulted in the formation of a thick epidermal layer (keratinization) that effectively covered all the impaired areas, achieving a wound contraction rate of 95.83±6.3% at the late stage of wound healing. Furthermore, immunohistochemistry staining for CD31 and TGF-β revealed that the HPE@Bilayer group had 22 blood vessels/field and 34%−66% immunoactive cells, respectively, after 14 days of healing. However, by day 21, angiogenesis and TGF-β expression had declined, demonstrating that the wounds had been successfully treated with minimal scarring.

Incubation with porcine urinary bladder matrix yields a late-stage wound transcriptome in endothelial cells and keratinocytes isolated from both diabetic and non-diabetic subjects.

Proper wound closure requires the functional coordination of endothelial cells (ECs) and keratinocytes. In the late stages of wound healing, keratinocytes become activated and ECs promote the maturation of nascent blood vessels. In diabetes mellitus, decreased keratinocyte activation and impaired angiogenic action of ECs delay wound healing. Porcine urinary bladder matrix (UBM) improves the rate of wound healing, but the effect of exposure to UBM under diabetic conditions remains unclear. We hypothesized that keratinocytes and ECs isolated from both diabetic and non-diabetic donors would exhibit a similar transcriptome representative of the later stages of wound healing following incubation with UBM. Human keratinocytes and dermal ECs isolated from non-diabetic and diabetic donors were incubated with and without UBM particulate. RNA-Seq analysis was performed to identify changes in the transcriptome of these cells associated with exposure to UBM. While diabetic and non-diabetic cells exhibited different transcriptomes, these differences were minimized following incubation with UBM. ECs exposed to UBM exhibited changes in the expression of transcripts suggesting an increase in the endothelial-mesenchymal transition (EndoMT) associated with vessel maturation. Keratinocytes incubated with UBM demonstrated an increase in markers of activation. Comparison of the whole transcriptomes with public datasets suggested increased EndoMT and keratinocyte activation following UBM exposure. Both cell types exhibited loss of pro-inflammatory cytokines and adhesion molecules. These data suggest that application of UBM may accelerate healing by promoting a transition to the later stages of wound healing. This healing phenotype is achieved in cells isolated from both diabetic and non-diabetic donors.

Hypothesis: Platelet-rich plasma accelerate diabetic wound healing via dynamic modulation of multiple signaling pathways

Diabetic wounds are a prevalent complication in patients with diabetes. Incremental platelet-rich plasma (PRP) administration has recently been used as an adjunct therapy for the treatment of diabetic ulcers. However, the exact signaling pathways involved in PRP-induced healing remain unclear. We speculated that PRP could mediate diabetic wound healing by dynamic modulation of signaling pathways including TGF-β/Smad, Wnt/β-catenin, Notch, NF-κB, MAPK, and PI3K/Akt, at different levels. PRP may have different effects (activation or inhibition) on different or even the same signal pathways depending on the stage of the healing process and concentration of growth factors within the PRP preparation. In the early stages of wound healing, some signaling pathways are initiated to reduce wound inflammation and oxidative stress, and promote angiogenesis and collagen regeneration. In the late stages of wound healing and scar formation, PRP may inhibit some signal pathways to prevent excessive fibroblast proliferation and deposition of extracellular matrix proteins such as collagen, thereby controlling excessive tissue proliferation at the wound site and minimizing scars. The various signaling pathways exhibit complex and context-dependent interactions; crosstalk between these pathways can lead to synergistic or antagonistic effects and regulate various cellular responses. This knowledge could be used to develop targeted therapies to optimize healing and reduce the risk of subsequent complications.

Tannic acid-loaded chitosan-RGD-alginate scaffolds for wound healing and skin regeneration

Hydrogels have drawn much attention in the field of tissue regeneration and wound healing owing to the application of biocompatible peptides to tailor structural features necessitating optimal tissue remodeling performance. In the current study, polymers and peptide were explored to develop scaffolds for wound healing and skin tissue regeneration. Alginate (Alg), chitosan (CS), and arginine-glycine-aspartate (RGD) were used to fabricate composite scaffolds crosslinked with tannic acid (TA), which also served as a bioactive. The use of RGD transformed the physicochemical and morphological features of the 3D scaffolds and TA crosslinking of the scaffolds improved their mechanical properties, specifically tensile strength, compressive Young’s modulus, yield strength, and ultimate compressive strength. The incorporation of TA as both a crosslinker and a bioactive allowed for 86% encapsulation efficiency and burst release of 57% of TA in 24 h, accompanied by an 8.5% steady release per day of up to 90% over 5 d. The scaffolds increased mouse embryonic fibroblast cell viability over 3 d, progressing from slightly cytotoxic to non-cytotoxic (cell viability >90%). Wound closure and tissue regeneration evaluations in a SpragueDawley rat wound model at predetermined wound healing time points highlighted the superiority of the Alg-RGD-CS and Alg-RGD-CS-TA scaffolds over the commercial comparator product and control. The scaffolds’ superior performance included accelerated tissue remodeling performance from the early to the late stages of wound healing, indicated by the lack of defects and scarring in scaffold-treated tissues. This promising performance supports the design of wound dressings that can act as delivery systems for the treatment of acute and chronic wounds.

Effects of Bioactive Compound, Ginsenoside Rb1 on Burn Wounds Healing in Diabetic Rats: Influencing M1 to M2 Phenotypic Trans

Panax notoginseng (P.notoginseng) has been used traditionally to treat traumatic injuries. Ginsenoside Rb1, a key active ingredient derived from P.notoginseng, has received a lot of interest due to its anti-inflammatory, bacteriostatic, and growth-promoting effects on cells. The therapeutic benefits of ginsenoside Rb1 on burn wounds in STZ-induced diabetic rats, as well as the probable underlying processes, were investigated in this work. The skin wound healing effect of ginsenoside Rb1 (0.25 and 0.5% w/w) in a rat model of burn wounds in diabetic rats was observed at various time points after treatment. On days 5 and 19 following treatment, immunohistochemistry and Western blot analysis for Interleukin 1 beta (IL-1β), Tumour necrosis factor-α (TNF-α), Cluster of Differentiation 68 (CD68) and Cluster of Differentiation 163 (CD163) of biological tissues were done. The macroscopic observation was used to track the healing of skin wounds at various periods. The protein expression of CD68 and CD163, which serve as M1 and M2 macrophage markers, was examined in detail. More notably, the ability of ginsenoside Rb1 to alter inflammatory markers (IL-6) and anti-inflammatory markers (IL-10), influence on hydroxyproline and hexosamine was observed. As indicated by increased CD163 (M2) and reduced CD68 (M1) on day 5, ginsenoside Rb1 effectively flips the M1 to M2 phenotypic transition at the right time to improve burn wound healing in diabetic rats. Ginsenoside Rb1 (0.5 % w/w) treatment showed higher tensile strength, anti-inflammatory properties, antioxidant properties, increased tissue hexosamine and hydroxyproline levels. Skin tissue morphology was significantly improved following 19 days of ginsenoside Rb1 (0.5% w/w) therapy, according to hematoxylin-eosin and Masson’s trichrome staining. Furthermore, Ginsenoside Rb1 (0.5% w/w) favoured the inflammatory phase of burn wound healing (IL-6), assisted the proliferation process (IL-10) and had considerably lower expression of IL-1β and TNF-α on the later stage of wound healing. Overall, the data showed that ginsenoside Rb1 (0.5 % w/w) accelerates burn wound healing in diabetic rats through a mechanism that may be linked to the M1 to M2 phenotypic shift.

Multifunctional antibiotics-free hydrogel dressings with self-regulated nitric oxide-releasing kinetics for improving open wound healing.

Healing of large open wounds remains a major challenge in clinics due to the high risk of bacterial infection and slow healing rates, while excessive use of antibiotics would cause enhanced antibiotic resistance and reduced biocompatibility. Herein, we developed a multifunctional hydrogel dressing (GCNO) through embedding nitrosothiol-conjugated chitosan into a crosslinked gelatin methacrylate (GelMA) network via hydrogen bonding, which presented self-regulated nitric oxide (NO) release kinetics for temporally controlled bacterial elimination and wound repair. At early stages after implantation, the positively charged chitosan molecules of the GCNO hydrogel precursors and release of a high level of NO from the GCNO hydrogel demonstrated effective coordinated antimicrobial capability, thus preventing wound infection in the early stages of healing. While at later stages of wound healing, the hydrogel could sustainably release low levels of NO to stimulate the proliferation and migration of fibroblasts and endothelial cells, leading to accelerated angiogenesis and cell deposition at the wound area. GCNO hydrogels exhibited anti-bacterial and wound repair performance with excellent biocompatibility and biosafety. Overall, this antibiotic-free GCNO hydrogel could demonstrate self-adaptive NO release profiles to prevent bacterial infection in early stages of wound healing while accelerating skin regeneration at later stages, which may offer new insights for the clinical management of large open wounds in clinics.

Development and evaluation of a novel topically applied sildenafil citrate hydrogel and its influence on wound healing in dogs.

To develop a topical sildenafil hydrogel and evaluate its effect on wound healing in dogs. 6 purpose-bred, sexually intact, adult Beagles. Hydrogels containing sildenafil citrate, N-methyl-2-pyrrolidone, propylene glycol, and poloxamer 407 were developed. Four excision wounds were created along the dorsum of the dogs. Each wound was treated for 21 days with a nonadherent bandage (C) or with a hydrogel containing 0% (G), 5% (5S), or 10% (10S) sildenafil. Daily bandage changes with wound imaging were performed. Biopsy specimens were collected 5 times. Hydrogels were homogenous at room temperature and released > 90% of the sildenafil within 8 hours in vitro. Time to first granulation tissue was significantly shorter for the sildenafil groups (mean ± SD, 2.8 ± 0.8 days [5S and 10S]), compared with the control groups (5.2 ± 0.4 days [C] and 6.3 ± 1.4 days [G]). The G wounds had a 10% to 14% lower contraction rate, compared with the C, 5S, and 10S wounds. 5S wounds had a total wound area 0.7 ± 0.3 cm2 larger than 10S wounds. No significant differences were present when C wounds were compared with 5S and 10S wounds for total wound area, contraction, or epithelialization. Histologic acute inflammatory scores were higher for 5S and 10S wounds in the early and late stages of wound healing, with higher reparative scores on day 7. Neovascularization was higher for 10S wounds on day 7 and 14. The topical sildenafil hydrogel promoted early granulation tissue, which may be beneficial for secondary wound closure in clinical settings.

Dracorhodin Perchlorate Regulates the Expression of Inflammatory Cytokines through the TLR4 Pathway and Improves Skin Wound Healing in Diabetic Rats.

Background Dragon's blood is a natural medicine with hemostatic and blood-activating effects and is used to promote wound healing. Dracorhodin perchlorate (DP) is a stable form of dracarhod and is used as a substitute for cochinchinenin. DP promotes the proliferation of rat fibroblasts and promotes wound healing in rats. Methods DP ointment (0.2 mg/mL) was applied to the skin wounds of nondiabetic and diabetic rats, and the skin of the wound was collected. Wound healing rate, H&E staining, Masson staining, TLR4 pathway, related inflammatory factors, nitric oxide synthase, and so forth were detected. Results DP treatment alleviated the prolonged inflammatory cell infiltration time and the increase in the TLR4 pathway and inflammatory factors caused by diabetes. DP also promoted wound healing by increasing eNOS protein expression and NO content in the later stage of wound healing. Conclusion DP promotes wound healing in diabetic rats by regulating the TLR4 pathway and related inflammatory factors. Therefore, adjuvant treatment of DP can be developed for diabetic wound healing.