Residual Wound Area Research Articles

Fermented Polyherbal Formulation Ameliorates the Severity of Acute Multiple Antibiotics-Resistant Pseudomonas aeruginosa-Infected Burn Wound in a Rat Burn Model.

Pseudomonas aeruginosa, a Gram-negative opportunistic bacterium, has emerged as a cause of life-threatening infections in burn wounds. Current therapeutic approaches through wound dressings and systemic medicines are far from satisfactory; resistance to more than two antibiotics shown by pathogens contributes to failures of therapy causing mortality. This animal study was conducted to check the efficacy of one Ayurveda-based fermented polyherbal preparation (AP 01) against multiple antibiotics-resistant (MAR) P. aeruginosa HW01-infected rat burn wounds. AP-01 was applied on artificially infected burn wound on a rat model infected with MAR P. aeruginosa to register the healing effects in terms of reduction in residual wound area percentage, the presence of C-reactive protein in blood, and the presence of viable bacteria colony. Topical application with conventional antibiotics served as a positive control. The polyherbal preparation had reduced the infected residual burn wound area at 40.63% ± 0.69 from the initial burn wound area within two weeks after a single intervention, whereas residual burn wound area remained much higher in the case of animals left untreated and in the case of the animals treated with control drug. Restoration to the normalcy of serum C-reactive protein level was also achieved earlier in the case of polyherbal AP-01-treated groups than in other groups. Fermented formulations using components of AP-01 singly or in different combinations had never been tested earlier for topical application in infected burn wound. The formulation of AP-01 was found superior in terms of the rate of healing and control of infection by MAR P. aeruginosa strains in burn wounds in rat models.

Simvastatin nanocrystals-based dissolving microneedles for wound healing

Currently, one of the main problems encountered in wound healing therapy is related to inefficient drug delivery. However, dissolving microneedles (DMNs) can be administered percutaneously to effectively deliver a drug to a deep wound area. Simvastatin (SIM) can promote wound healing, albeit its insolubility in water limits its application. Here, we designed a DMNs (SIM-NC@DMNs) drug delivery system loaded with SIM nanocrystals (SIM-NC) and evaluated its efficacy in wound healing. Based on our observations, the dissolution performance of insoluble SIM is significantly improved after the preparation of SIM-NC. For example, the saturation solubility of SIM-NC in deionized water and PBS increased by 150.57 times and 320.14 times, respectively. After the SIM-NC@DMNs are deeply inserted into the wound, the needle portion, which is composed of hyaluronic acid (HA), dissolves rapidly, and the SIM-NC loaded on the needle portion is efficiently released into the deep wound area for optimal therapeutic efficacy. The combination of NC and DMNs makes this system further effective for wound healing. Our cumulative work suggests that the newly developed SIM-NC@DMNs possess great potential in accelerating wound healing. By day 12 after treatment, the residual wound area in the Control group was 21.34 %, while the residual wound area in the SIM-NC@DMNs group was only 2.36 %. This result as well as provides certain evidence of its efficacy for wound healing therapy. The SIM-NC@DMNs drug delivery system may become an efficient treatment modality that promotes wound healing, with a promising potential in the field of wound healing research.

FastSkin® Concept: A Novel Treatment for Complex Acute and Chronic Wound Management.

Successful treatments for acute and chronic skin wounds remain challenging. The goal of this proof-of-concept study was to assess the technical feasibility and safety of a novel wound treatment solution, FastSkin®, in a pig model. FastSkin® was prepared from skin micrografts patterned in blood using acoustic waves. Upon coagulation, the graft was transferred on a silicone sheet and placed on wounds. Six full-thickness wounds were created at the back of two pigs and treated with either FastSkin®, split-thickness skin graft (positive control), a gauze coverage (negative control, NC1), or blood patterned without micrografts (negative control, NC2). Silicone sheets were removed after 7, 14, and 21 days. Wound healing was monitored for six weeks and evaluated macroscopically for re-epithelialization and morphometrically for residual wound area and wound contraction. Tissue regeneration was assessed with histology after six weeks. Re-epithelialization was faster in wounds covered with FastSkin® treatments compared to NC2 and in NC2 compared to NC1. Importantly, an enhanced collagen organization was observed in FastSkin® in contrast to NC treatments. In summary, two clinically approved skin wound treatments, namely micrografting and blood clot graft, were successfully merged with sound-induced patterning of micrografts to produce an autologous, simple, and biologically active wound treatment concept.

Novel cell culture system for monitoring cells during continuous and variable negative-pressure wound therapy.

Although the clinical efficacy of negative-pressure wound therapy (NPWT) is well known, many of its molecular biological mechanisms remain unresolved, mainly due to the difficulty and paucity of relevant in vitro studies. We attempted to develop an in vitro cell culture system capable of real-time monitoring of cells during NPWT treatment. A novel negative-pressure cell culture system was developed by combining an inverted microscope, a stage-top incubator, a sealed metal chamber for cell culture, and an NPWT treatment device. Human keratinocytes, PSVK-1, were divided into ambient pressure (AP), continuous negative-pressure (NPc), and intermittent negative-pressure (NPi) groups and cultured for 24h with scratch assay using our real-time monitoring system and device. Pressure inside the device, medium evaporation rate, and the residual wound area were compared across the groups. Pressure in the device was maintained at almost the same value as set in all groups. Medium evaporation rate was significantly higher in the NPi group than in the other two groups; however, it had negligible effect on cell culture. Residual wound area after 9h evaluated by the scratch assay was significantly smaller in the NPc and NPi groups than in the AP group. We developed a negative-pressure cell culture device that enables negative-pressure cell culture under conditions similar to those used in clinical practice and is able to monitor cells under NPWT. Further experiments using this device would provide high-quality molecular biological evidence for NPWT.

RJX Improves Wound Healing in Diabetic Rats.

BackgroundWe recently reported the clinical safety profile of RJX, a well-defined intravenous GMP-grade pharmaceutical formulation of anti-oxidant and anti-inflammatory vitamins as active ingredients, in a Phase 1 study in healthy volunteers (ClinicalTrials.gov Identifier: NCT03680105) (Uckun et al., Front. Pharmacol. 11, 594321. 10.3389/fphar.2020.594321). The primary objective of the present study was to examine the effects of GMP-grade RJX on wound and burn injury healing in diabetic rats.MethodsIn the present study, a rat model of T2DM was used that employs HFD in combination with a single injection of STZ intraperitoneally (i.p) at a moderate dose level (45 mg/kg). Anesthetized diabetic rats underwent full-thickness skin excision on the back or were subjected to burn injury via a heated brass probe and then started on treatments with normal saline (NS = vehicle) or RJX administered via intraperitoneal injections for three weeks.FindingsNotably, diabetic rats treated with the 1.25 mL/kg or 2.5 mL/kg RJX (DM+RJX groups) rapidly healed their wounds as fast as non-diabetic control rats. Inflammatory cell infiltration in the dermis along with fibrin and cell debris on the epithelial layer persisted for up to 14 days in the DM+NS group but not in RJX-treated groups. The histopathological score of wound healing on days 7 and 14 was better in diabetic rats treated with RJX than diabetic rats treated with NS and comparable to the scores for non-diabetic healthy rats consistent with an accelerated healing process. The residual wound area of RJX-treated rats was significantly smaller than that of NS-treated diabetic rats at each evaluation time point (P<0.001). The accelerating effect of RJX on diabetic wound healing was dose-dependent. We obtained similar results in the burn injury model. Our results demonstrate that RJX – at a dose level >10-fold lower than its clinical maximum tolerated dose (MTD) – accelerates the healing of excision wounds as well burn injury in diabetic rats.

Evaluation of 20(S)-ginsenoside Rg3 loaded hydrogel for the treatment of perianal ulcer in a rat model

BackgroundAs a kind of common complication of the surgery of perianal diseases, perianal ulcer is known as a nuisance. This study aims to develop a kind of 20(S)-ginsenoside Rg3 (Rg3)-loaded hydrogel to treat perianal ulcers in a rat model. MethodsThe copolymers PLGA1600-PEG1000-PLGA1600 were synthesized by ring-opening polymerization process and Rg3-loaded hydrogel was then developed. The perianal ulcer rat model was established to analyze the treatment efficacy of Rg3-loaded hydrogel for ulceration healing for 15 days. The animals were divided into control group, hydrogel group, free Rg3 group, Rg3-loaded hydrogel group, and Lidocaine Gel® group. The residual wound area rate was calculated and the blood concentrations of interleukin-1 (IL-1), interleukin-6 (IL-6), and vascular endothelial growth factor (VEGF) were recorded. Hematoxylin and eosin (H&E) staining, Masson's Trichrome (MT) staining, and tumor necrosis factor α (TNF-α), Ki-67, CD31, ERK1/2, and NF-κB immunohistochemical staining were performed. ResultsThe biodegradable and biocompatible hydrogel carries a homogenous interactive porous structure with 10 μm pore size and five weeks in vivo degradation time. The loaded Rg3 can be released sustainably. The in vitro cytotoxicity study showed that the hydrogel had no effect on survival rate of murine skin fibroblasts L929. The Rg3-loaded hydrogel can facilitate perianal ulcer healing by inhibiting local and systematic inflammatory responses, swelling the proliferation of nuclear cells, collagen deposition, and vascularization, and activating ERK signal pathway. ConclusionThe Rg3-loaded hydrogel shows the best treatment efficacy of perianal ulcer and may be a candidate for perianal ulcer treatment.

Effectiveness of Blue light photobiomodulation therapy in the treatment of chronic wounds. Results of the Blue Light for Ulcer Reduction (B.L.U.R.) Study.

Lower limb ulcers not responding to standard treatments after 8 weeks are defined as chronic wounds, and they are a significant medical problem. Blue light (410-430 nm) proved to be effective in treating wounds, but there is a lack of data on chronic wounds in clinical practice. The aim of the study was to determine if blue light photobiomodulation with EmoLED (Emoled Srl, Sesto Fiorentino, Florence, Italy) medical device in addition to standard of care is more effective compared to standard of care alone in promoting re-epithelialization of chronic wounds of lower limbs in 10 weeks. Ninety patients affected by multiple or large area ulcers were enrolled. To minimize all variabilities, each patient has been used as control of himself. Primary endpoint was the comparison of the re-epithelialization rate expressed as a percentage of the difference between the initial and final area. Secondary endpoints were: treatment safety, pain reduction, wound area reduction trend over time, healing rate. At week 10, the wounds treated with EmoLED in addition to standard care showed a smaller residual wound area compared to the wounds treated with standard of care alone: 42.1% vs. 63.4% (P=0.029). The difference is particularly evident in venous leg ulcers, 33.3% vs. 60.1% (P=0.007). 17 treated wounds and 12 controls showed complete healing at week 10. Patients showed a significant reduction in pain (P=2×10-7). Blue light treatment in addition to standard of care accelerates consistently the re-epithelialization rate of chronic wounds, especially venous leg ulcers and increases the chances of total wound healing in 10 weeks.

Optimizing microenvironment by integrating negative pressure and exogenous electric fields via a flexible porous conductive dressing to accelerate wound healing.

Wound healing is a complex and sequential biological process that involves multiple stages. Current treatments for nonhealing or chronic wounds are unsatisfactory as they exert a single effect on one specific activity. Herein, we constructed a silver nanowire (AgNW)-based, three-dimensional (3D), porous foam dressing that is flexible and conductive. This conductive foam dressing was composed of AgNWs modified with a stable hydrophobic coating and porous polyurethane (PU), providing a skeleton to support the 3D conductive networks. The AgNWs-PU foam dressing exhibited favorable biocompatibility, outstanding electrical properties, excellent bending-compression durability, and long-term stability under wet conditions, making it suitable for wound treatment. Via the conductive foam dressing, negative pressure and exogenous wound directional electric fields (EFs) could be integrated for simultaneous implementation, and the artificial jointly constructed microenvironment promoted wound healing in a system. This novel "all-in-one" device presented intrinsic multifunctionality, including the drainage of pus and necrotic tissue, mitigation of inflammation, promotion of cell proliferation, direction of keratinocyte migration, and induction of angiogenesis. An immunohistochemical assay and western blot analysis illustrated that the angiogenesis and cell proliferation pathways in the tissue were significantly activated when this novel therapy was adopted. More importantly, the practical performance of this "all-in-one" device was demonstrated by assessment of full-thickness defect wounds in model pigs. Comparing the percentage of residual wound area after administration of traditional treatment (25.82 ± 3.52%) and the novel treatment (3.07 ± 1.23%) demonstrated the promising applications of this novel treatment in clinical wound healing.

Mechanism study of dendritic epidermal T lymphocytes in promoting healing of full-thickness skin defects wound on mice by regulating the proliferation and differentiation of epidermal stem cells in mice

Mechanism study of dendritic epidermal T lymphocytes in promoting healing of full-thickness skin defects wound on mice by regulating the proliferation and differentiation of epidermal stem cells in mice

Antimicrobial and anti-inflammatory potential of Angelica dahurica and Rheum officinale extract accelerates wound healing in Staphylococcus aureus-infected wounds

Wound infection is a serious clinical problem, and the most common infection-causing bacteria are Staphylococcus aureus and Pseudomonas aeruginosa. Angelica dahurica and Rheum officinale extract (ARE) was reported to accelerate excisional wound healing in rats. In this study, we investigated the therapeutic effects of ARE on bacterial-infected wounds. Thirty Sprague-Dawley rats were divided into three groups: normal saline (NS), ARE, and biomycin ointment (BO). Full-thickness dorsal excisions in all the rats were infected with 108 colony-forming units of S. aureus; the treatments were applied once daily for 7 days. Results showed that the residual wound area in ARE group was smaller than those in NS and BO groups. TBCs on wound sites gradually decreased in ARE and BO groups. The body temperature and plasma inflammatory cytokines (TNF-α, IL-6) levels increased after bacterial infection at 24 h in all groups. After treatment, BT and inflammatory cytokines levels decreased in ARE group. Histological observations showed ARE group exhibited earlier scab formation, denser dermal granulation tissue, thicker epidermis, and more angiogenesis markers than the other groups. In conclusion, ARE accelerated wound healing in S. aureus-infected wounds. We proposed ARE exhibited potential antimicrobial and anti-inflammatory effects and stimulated angiogenesis, thus improving healing in infected wounds.

Effects of dendritic epidermal T cells on proliferation and apoptosis of epidermal cells in wound margin of mice

Effects of dendritic epidermal T cells on proliferation and apoptosis of epidermal cells in wound margin of mice

Effects of pure and ozonated sunflower seed oil (Helianthus annuus) on hypergranulation tissue formation, infection and healing of equine lower limb wounds

This study was undertaken to evaluate the therapeutic effects of topical application of pure sunflower seed oil (oil group) and ozonated sunflower seed oil (ozone group) on acute cutaneous wound healing in eight healthy horses. The control group was treated with 0.9% sodium chloride. Two wounds were surgically produced on each horse on the proximal epiphysis of the metacarpus on the dorsal aspect of each forelimb. Wound area and contraction were measured on days 0, 3, 7, 14 and 21. Biopsy samples were taken to evaluate epithelial hyperplasia, inflammation, exuberant granulation tissue, exudate type, angiogenesis, and fibroplasia. Culture swabs were also collected. Wound contraction at 21 days for the oil group was 52.68%, for the ozone group was 72.16%, and for the control group (0.9% sodium chloride) was 34.80%. The ozone group had a significantly smaller wound size and a residual wound area than the control and the oil groups, on days 14 and 21. The control-wounds and oil-wounds had suppurative exudate and the presence of Streptococcus zooepidemicus. Neutrophilic inflammatory infiltrate was observed in all groups. Granulation tissue was observed on day 7 in all groups, but exuberant granulation tissue was observed only in the control group on days 14 and 21. Reepithelialization was observed on day 14 in the ozone group. In conclusion, these results demonstrate that topical application of ozonated sunflower seed oil accelerates acute cutaneous wound repair in horses, preventing hypergranulation tissue and infection, and that it is superior to treatment with pure sunflower seed oil and 0.9% sodium chloride.

Fibronectin precoating wound bed enhances the therapeutic effects of autologous epidermal basal cell suspension for full-thickness wounds by improving epidermal stem cells\u2019 utilization

BackgroundAutologous epidermal basal cell suspension therapy has been proven to be one of the most effective treatments for full-thickness wounds. However, we found there remain obvious defects that significantly confined the utilization and function of the epidermal basal cells (EBCs), especially the epidermal stem cells (ESCs) in it. This study investigated whether precoating fibronectin (FN) on the wound bed before spraying EBCs could overcome these defects and further explored its possible mechanisms.MethodsIn the in vitro study, EBCs were isolated from the donor skin of patients who needed skin grafting. Different concentrations of FN were used to precoat culture dishes before cell culture; the adherent efficiency, proliferation and migration ability of ESCs were analyzed and compared with traditional collagen IV precoating.In the in vivo study, Sprague–Dawley (SD) rats with full-thickness skin wounds were selected as full-thickness wounds’ model. For the experiment groups, 20 μg/ml FN was precoated on the wound bed 10 min before EBC spray. The quality of wound healing was estimated by the residual wound area rate, wound healing time, and hematoxylin and eosin (H&E) staining. Expression of ESC markers, neovascular markers, inflammation markers, and collagen formation and degradation markers was elucidated by immunohistochemistry (IHC), immunofluorescence (IF), western blot (WB), and RT-qPCR analysis.ResultsThe in vitro study showed that the dishes precoated with 20 μg/ml FN had a similar adherent efficiency and colony formation rate with collagen IV, but it could improve the proliferation and migration of ESCs significantly. Similarly, in the in vivo study, precoating FN on wound bed before EBC spray also significantly promote wound healing by improving ESCs’ utilization efficiency, promoting angiogenesis, decreasing inflammations, and regulating collagen formation and degradation.ConclusionFN precoating wound bed before EBC spray could significantly promote full-thickness wound healing by improving the utilization and function of the ESCs and further by promoting angiogenesis, decreasing inflammations, and regulating collagen formation and degradation.Graphical abstract

Effects of skin γδ T lymphocytes on wound healing of mice through regulating proliferation and differentiation of mice epidermal cells

Effects of skin γδ T lymphocytes on wound healing of mice through regulating proliferation and differentiation of mice epidermal cells

A novel approach to assess clinical competence of postgraduate year 1 surgery residents

ABSTRACTBackground: An increased demand for accountability and transparency in medicine have initiated a shift toward a more objective and standardized approach for postgraduate medical training.Objective: To develop and evaluate an objective method to assess clinical competence of postgraduate year 1 surgery residents.Design: Thirty-one postgraduate year 1 surgery residents, who had been trained in the Surgical School of Peking University First Hospital for one year, participated in an objective structured clinical examination as a final assessment of their clinical competence. A test station of irregular wound repair (debridement and suture) was specially designed to test the residents’ surgical integrative competence in a complex-trauma treatment procedure. A modified global rating scale, in combination with wound area measurement, was applied to evaluate residents’ surgical performance. The validity of the subjective global rating scale was evaluated by the objective measurement results from the software.Results: The global rating scale score had no obvious correlation with the area of the removed tissue and the residual wound area after the suture. There was significant difference in the debridement time and the residual wound area between 0–3 and >3 total stitches. There were significant differences in the area of the removed tissue between 0 and 1–2 grey stitches and 0 and 3–4 grey stitches, and in the residual wound area after suture between 0 and 3–4 grey stitches and 1–2 and 3–4 grey stitches.Conclusions: An irregular wound repair procedure could be an effective method to assess the integrative competence of surgery residents. The training for surgical thinking in the early stage of junior residents needs to be strengthened. The entire measurement process was more complex and time-consuming than expected. The possibility of measurement by simply counting the numbers of the key spots might be explored in the future.Abbreviations: ACS/APDS American College of Surgeons/Association of Program Directors in Surgery; GRS Global rating scale; LSD-T Least significant difference-test; OSATS Objective structured assessment of technical skills; OSCE Objective structured clinical examination; PBT Proficiency based training; PGY1 Postgraduate Year 1

Experience in managing an urban massive burn incident: The Hangzhou bus attack on 5 July 2014

BackgroundOn 5 July 2014, a suicide terrorist set a crowded bus on fire in Hangzhou, injuring 33 passengers. Among these, 19 adult victims with the most severe burns were triaged to our center. This is a single-center, descriptive study recording the prehospital response and in-hospital treatment of these patients. MethodsInformation on the attack, on-scene rescue, and patient triage was collected from public media, governmental, and hospital reports. Information on patient injury and our in-hospital procedures was collected from the emergency registry and patient records. ResultsOf the 80 passengers in the burning bus, 33 were injured. The total burn surface area (TBSA) of the 19 most severely injured patients triaged to our hospital ranged from 25% to 95% (mean 48.3±2.08%). Two patients had a TBSA of >90% (92% and 95%) and eight had a TBSA of >60%. Nineteen cases of inhalation injury were diagnosed, eight of which were severe. The emergency center performed 14 bedside escharotomies, 14 central venous catheter (CVC) implantations, and one cardiopulmonary resuscitation (CPR). Approximately 131000ml of resuscitation fluid was infused within the first 24h and 111000ml within the second; further, 160230ml of plasma and 4100ml of red blood cells were infused during the antishock stage.All victims were transported to the burn ward to receive burn-centered multidisciplinary care. The respiratory team conducted 121 bronchoscopies. A total of 89 operations were performed, and the residual wound area decreased dramatically. After 124 days of extensive therapy, complete wound healing was observed and all patients entered the rehabilitation stage. ConclusionAdequate preparation, including planning and disaster drills, is crucial for handling mass casualty events. Efficient and precise first rescue and triage can reduce prehospital mortality, and burn-centered multidisciplinary care and hospital–government cooperation helps reduce in-hospital mortality. Nevertheless, lessons can be drawn from this incident to be better prepared for future disasters.

Fabrication and structure analysis of poly(lactide-co-glycolic acid)/silk fibroin hybrid scaffold for wound dressing applications

Silk fibroin (SF) and poly(lactide-co-glycolic acid) (PLGA) have been proved to be invaluable polymers in the field wound healing. This study aims at optimizing the electrospinning process of those polymers to make a hybrid membrane as a chronic wounds dressing. After characterizing the scaffolds, PLGA/SF (2:1), and PLGA scaffolds were selected for further study according to their superior tensile mechanical properties. The attachment and proliferation of mouse fibroblasts (L929) on scaffolds were measured using colorimetric assay and scanning electron microscopy. Furthermore, to evaluate the wound healing effect of the scaffolds in comparison with gauze and Comfeel® dressings, an excision wound model was conducted on diabetic rats. On the postoperative days of 3, 6, 9, 12, and 15, residual wound area was calculated using macroscopic data. In vitro results showed that the attachment and proliferation of L929 were significantly increased on PLGA/SF (2:1) hybrid scaffold. Animal study and histopathological evaluation outcomes confirmed the in vitro results as well. On day 15, the residual wound area in PLGA/SF (2:1) hybrid membrane group was significantly smaller than PLGA and control groups. This promising scaffold has the potential to be used for the upcoming development of wound dressings with or without biological drugs.

Use of gene-modified keratinocytes and fibroblasts to enhance regeneration in a full skin defect

With the development of cell-based gene transfer techniques, genetically modified human keratinocytes (Kc) and fibroblasts (Fb) have been proven to be a better choice in wound repair. This study was designed to construct in one step a gene-modified artificial skin by a genetically engineered Kc expressing PDGF-BB and Fb expressing VEGF(165) and bFGF. The wound healing effect in a full-thickness wound model was then observed. Unmodified artificial skin served as control. On the post-operative days7, 14, and 21, residual wound area was calculated and skin wound tissues were subjected to biopsy for further investigation. Compared with unmodified artificial skin, gene-modified artificial skin resulted in a reduced wound contraction and a well-organized human epidermis and better formed dermis. The results suggest that our two-layer, gene-modified artificial skin improved both vascularization and epidermalization for skin regeneration. This technique could bring about a new approach in the treatment of burns and chronic wounds.

Effect of hBD2 Genetically Modified Dermal Multipotent Stem Cells on Repair of Infected Irradiated Wounds

Deficiencies in repair cells and infection are two of the main factors that can hinder the process of wound healing. In the present study, we investigated the ability of human beta-defensin-2 (hBD2) genetically modified dermal multipotent stem cells (dMSCs) to accelerate the healing irradiated wounds complicated by infections. An hBD2 adenovirus expression vector (Adv-hBD2) was firstly constructed and used to infect dMSCs. The antibacterial activity of the supernatant was determined by Kirby-Bauer method and macrodilution broth assay. Time to complete wound healing, residual percentage of wound area, and the number of bacteria under the scar were measured to assess the effects of Adv-hBD2-infected dMSC transplantation on the healing of irradiated wounds complicated by Pseudomonas aeruginosa infection. Results showed that the supernatant from Adv-hBD2-infected dMSCs had obvious antibacterial effects. Transplantation of Adv-hBD2-infected dMSCs killed bacteria in the wound. The complete wound healing time was 19.8 ± 0.45 days, which was significantly shorter than in the control groups (P < 0.05). From 14 days after transplantation, the residual wound area was smaller in the experimental group than in the control groups (P < 0.05). In conclusion, we found that transplantation of hBD2 genetically modified dMSCs accelerated the healing of wounds complicated by P. aeruginosa infection in whole body irradiated rats.

Effect of Polarized Light Emitting Diode Irradiation on Wound Healing

We propose a new phototherapy using polarized light from light emitting diode (LED). The purpose of this study is to clarify the effect of polarized LED irradiation on wound healing. Five groups were classified: control (C), unpolarized (U), linearly polarized (L), right circularly polarized (RC), and left circularly polarized (LC) LED irradiation. In vitro study, fibroblast cell cultures were irradiated, and cellular proliferation was evaluated with a WST-8 assay. In vivo study, full-thickness skin defect of 20 mm diameter was created on the dorsal side of rats. The ratio of the residual wound area was measured, and expression of type 1 and type 3 procollagen mRNA in granulation tissue was determined by real-time reverse transcription polymerase chain reaction method. The cellular proliferation rates of group RC and L were significantly higher than other groups. The ratio of the residual wound area of group RC and L was significantly reduced than group C and U. Expression of type 1 procollagen mRNA in group RC was found to be significantly increased about 1.5-fold in comparison with the group C. There were no significant differences for type 3 procollagen. The right circularly polarized light and linearly polarized light promoted the process of wound healing by increasing the proliferation of fibroblasts, and the right circularly polarized light increased the expression of type 1 procollagen mRNA. The effectiveness of right circularly polarized light suggests that some optical active material, which has a circular dichroic spectrum, takes part in a biochemical reaction.