Delayed Grafting as a Valid Technique in Burn Management: Experience from a Burn Unit in Oman

Background: Early excision and grafting has been the preferred method of managing major burns around the world since 1970. Considering the advances in health care and the development of new antibiotics over the past 50 years, delayed grafting as a technique for the management of burns over 15%-20% of total body surface area (TBSA) could have comparable results to that of early excision. This study aims to highlight the outcomes of practicing delayed grafting in burn patients. Methods: A case series analysis was performed of 51 patients who were admitted to the burns unit in Sultan Qaboos Hospital Salalah with over 20% TBSA between January 2014 and December 2019. The patients received prophylactic antibiotics and silver sulphadiazine dressing until the burn eschar had completely separated, followed by grafting. Results: Two patients were lost during the entire duration of the study. The mortality rate was comparable to that of early excision, while the rate of hypertrophic scarring was lower than the range reported by other studies. Conclusion: In the management of patients with over 20% TBSA, delayed grafting after complete separation of eschar is still a valid technique.

Integration of Multiple Spectral Data via a Logistic Regression Algorithm for Detection of Crop Residue Burned Areas:A Case Study of Songnen Plain,Northeast China

The burning of crop residues in fields is a significant global biomass burning activity which is a key element of the terrestrial carbon cycle,and an important source of atmospheric trace gasses and aerosols.Accurate estimation of cropland burned area is both crucial and challenging,especially for the small and fragmented burned scars in China.Here we developed an automated burned area mapping algorithm that was implemented using Sentinel-2 Multi Spectral Instrument(MSI)data and its effectiveness was tested taking Songnen Plain,Northeast China as a case using satellite image of 2020.We employed a logistic regression method for integrating multiple spectral data into a synthetic indicator,and compared the results with manually interpreted burned area reference maps and the Moderate-Resolution Imaging Spectroradiometer(MODIS)MCD64A1 burned area product.The overall accuracy of the single variable logistic regression was 77.38%to 86.90%and 73.47%to 97.14%for the 52TCQ and 51TYM cases,respectively.In comparison,the accuracy of the burned area map was improved to 87.14%and 98.33%for the 52TCQ and 51TYM cases,respectively by multiple variable logistic regression of Sentind-2 images.The balance of omission error and commission error was also improved.The integration of multiple spectral data combined with a logistic regression method proves to be effective for burned area detection,offering a highly automated process with an automatic threshold determination mechanism.This method exhibits excellent extensibility and flexibility taking the image tile as the operating unit.It is suitable for burned area detection at a regional scale and can also be implemented with other satellite data.

Nomogram for predicting the risk of anxiety and depression in patients with non-mild burns

BACKGROUND Post-burn anxiety and depression affect considerably the quality of life and recovery of patients;however,limited research has demonstrated risk factors associated with the development of these conditions.AIM To predict the risk of developing post-burn anxiety and depression in patients with non-mild burns using a nomogram model.METHODS We enrolled 675 patients with burns who were admitted to The Second Affiliated Hospital,Hengyang Medical School,University of South China between January 2019 and January 2023 and met the inclusion criteria.These patients were randomly divided into development(n=450)and validation(n=225)sets in a 2:1 ratio.Univariate and multivariate logistic regression analyses were conducted to identify the risk factors associated with post-burn anxiety and depression dia-gnoses,and a nomogram model was constructed.RESULTS Female sex,age<33 years,unmarried status,burn area≥30%,and burns on the head,face,and neck were independent risk factors for developing post-burn anxiety and depression in patients with non-mild burns.The nomogram model demonstrated predictive accuracies of 0.937 and 0.984 for anxiety and 0.884 and 0.923 for depression in the development and validation sets,respectively,and good predictive per-formance.Calibration and decision curve analyses confirmed the clinical utility of the nomogram.CONCLUSION The nomogram model predicted the risk of post-burn anxiety and depression in patients with non-mild burns,facilitating the early identification of high-risk patients for intervention and treatment.

Community Knowledge and Attitude about Burns First Aid (BFA) in Jazan, Saudi Arabia

Introduction and Significance: Burn injury (BI) is a considerable health issue which is responsible for around 300,000 deaths and affecting about 11 million people every year worldwide. In Saudi Arabia, the prevalence of BIs array from 112 to 518 per 100,000 per year. The appropriate awareness of performing first aid could facilitate to improve the outcomes of burns. Purpose and Objectives: To appraise the community that acknowledges burns, first aid, and associated factors among the community population in Jazan City, Saudi Arabia. The paper aims to identify limitations to encourage additional research and persuade legislators to develop improved burn-injury care recommendations and training programs. Materials and Methods: An observational-based sample survey was conducted among the people who live in Jazan City aging 13 years or more, during April 5 to May 5, 2023. Data collection was done by a validated online self-administrated questionnaire sent randomly to community members in different parts of Jazan City via social media platforms. Collected data were coded and cleaned by an excel program, and finally exported on SPSS 26.0 software. The variables were analyzed using descriptive statistics like frequencies and percentages. Also, the Chi-square test was used to investigate the relation between different variables, with a significance value of P Results: This study included 243 participants (about 62%) among them were mostly male participants (151) having a university degree. The majority of participants 75% did not take any form of BFA training in the past. This study shows that 69.9% of the participants have inadequate awareness, despite 72% having a constructive attitude towards burn first aid. Previous burn-related first aid training was significantly associated with participants’ knowledge of BFA at a p-value less than 0.05. Conclusion: This study indicates a high frequency of Jazan population having inadequate knowledge of burn first aid despite the high prevalence of a favorable attitude. There is a need to develop an effective nationwide burn prevention program and early burn first aid treatment in Saudi Arabia and promote a consistent guideline for burn first aid.

Alkali burn injury model of meibomian gland dysfunction in mice

AIM:To establish a stable,short-time,low-cost and reliable murine model of meibomian gland dysfunction(MGD).METHODS:A filter paper sheet soaked in 1.0 mol/L sodium hydroxide(NaOH)solution was used to touch the eyelid margin of C57BL/6J mice for 10s to establish the model.The other eye was left untreated as a control group.Eyelid margin morphological changes and the meibomian glands(MGs)were observed by slit lamp microscopy on days 5 and 10 post-burn.Hematoxylin-eosin(HE)staining and Oil red O staining were adopted in detecting the changes in MGs morphology and lipid deposition.Real-time polymerase chain reaction,Western blot,immunofluorescence staining and immunohistochemical staining were used to detect interleukin(IL)-6,IL-1β,IL-18,tumor necroses factor(TNF)-α,interferon(IFN)-γ,nicotinamide adenine dinucleotide phosphate(NADPH)oxidase 4(NOX4),3-nitroturosine(3-NT),4-hydroxynonenal(4-HNE)and cytokeratin 10(K10)expression changes in MGs.RESULTS:MGs showed plugging of orifice,glandular deficiency,abnormal acinar morphology,ductal dilatation,and lipid deposition after alkali burn.The expressions of IL-6,IL-18,IL-1β,IFN-γ,and TNF-αindicators of inflammation and oxidative stress in MGs tissues were significantly increased.Abnormal keratinization increased in the MG duct.CONCLUSION:A murine model of MGD is established by alkali burn of the eyelid margin that matches the clinical presentation of MGD providing a stable,short-time,lowcost,and reliable MGD model.The new method suggests efficient avenues for future research.

Nonlinear dynamics of the reversed shear Alfvén eigenmode in burning plasmas

In a tokamak fusion reactor operated at steady state,the equilibrium magnetic field is likely to have reversed shear in the core region,as the noninductive bootstrap current profile generally peaks off-axis.The reversed shear Alfvén eigenmode(RSAE)as a unique branch of the shear Alfvén wave in this equilibrium,can exist with a broad spectrum in wavenumber and frequency,and be resonantly driven unstable by energetic particles(EP).After briefly discussing the RSAE linear properties in burning plasma condition,we review several key topics of the nonlinear dynamics for the RSAE through both wave-EP resonance and wave-wave coupling channels,and illustrate their potentially important role in reactor-scale fusion plasmas.By means of simplified hybrid MHD-kinetic simulations,the RSAEs are shown to have typically broad phase space resonance structure with both circulating and trapped EP,as results of weak/vanishing magnetic shear and relatively low frequency.Through the route of wave-EP nonlinearity,the dominant saturation mechanism is mainly due to the transported resonant EP radially decoupling with the localized RSAE mode structure,and the resultant EP transport generally has a convective feature.The saturated RSAEs also undergo various nonlinear couplings with other collective oscillations.Two typical routes as parametric decay and modulational instability are studied using nonlinear gyrokinetic theory,and applied to the scenario of spontaneous excitation by a finite amplitude pump RSAE.Multiple RSAEs could naturally couple and induce the spectral energy cascade into a low frequency Alfvénic mode,which may effectively transfer the EP energy to fuel ions via collisionless Landau damping.Moreover,zero frequency zonal field structure could be spontaneously excited by modulation of the pump RSAE envelope,and may also lead to saturation of the pump RSAE by both scattering into stable domain and local distortion of the continuum structure.

Multidisciplinary treatment of molten aluminum combined burn:An unusual case report

Molten aluminum is among the most common causes of burns in the metal industry.However,only few reports are available on molten aluminum injuries.Herein,we report an unusual case of molten aluminum burn.The patient had burns not only on the body surface but also in the respiratory tract and esophagus,adding to the difficulty of treatment.Multidisciplinary consultation and cooperation led to the development of a treatment plan for the patient,which included tracheotomy,respiratory management,endoscopic therapy,infection control,and psychological support.To our knowledge,this is the first report of molten aluminum-induced burns involving the face,neck,respiratory tract,esophagus,and eyes.We also describe our experience with multidisciplinary treatment for the management of molten aluminum burns.

Infection control and prevention in burn victims:The role of nurses

Burn injury is a major public health concern,with an estimated 180,000 deaths each year associated with burn-related infections.The majority of these occur in low-and middle-income countries,and almost two-thirds occur in the World Health Organization African and South-East Asia Regions.There is a risk of an escalation of burn injury site infections if nurses who are directly involved in burn care do not develop a mechanism to mitigate this risk in the coming years.Hence,this study aims at explaining what burn injuries are and how nurses can prevent the occurrence of infection among burn victims.This review analyzed published studies using keywords such as burn injury,infection in burn patients,and nurses’involvement in infection prevention and control(IPC)on search engines such as PubMed,Science Direct,and Google Scholar.The literature was retrieved and reviewed for eligibility to capture just the variables indicated in this seminar objective;the date range chosen in the literature search was from 2015 to 2023.The study found that many patients die from burn injuries as a result of exposure to infection and most nurses are not adequately informed about infection control.The study also found that nurses’responsibilities include proper hand hygiene,wound care,the use of personal protective equipment,antibiotic medication,cleaning the patient’s surroundings,and preventing patient cross-contamination.Burn injuries pose a significant risk to patients,necessitating infection control and prevention.Therefore,nurses in burn units should be informed on IPC practices and also educate patients,families,and coworkers on their importance.

Analysis of the Cicatricial Acceleration Method (MAC®) in Skin Repair in Wistar Rattus norvegicus with Induced Chemical Burns

Introduction: The cicatricial acceleration method (MAC®) promotes photobiological effects of an anti-inflammatory and healing nature. Its therapeutic radiation is emitted, producing photobiostimulant effects that result in rapid tissue repair and better tissue quality. The treatment of burns has always been a challenge, which involves both performing surgery and controlling and guiding scar regeneration, avoiding possible morbidities. Objective: To evaluate the effects of applying the MAC methodology with an AlGa (aluminum, gallium arsenide) laser on the time and quality of tissue repair in the skin of rats after induced chemical burns. Method: 22 adult male rats were subjected to a second-degree chemical burn on the back using 50% trichloroacetic acid. After the burns, the animals were randomly separated into 2 groups: control and experimental. The control group (G1) received placebo laser therapy and the laser group (G2) underwent laser irradiation with an energy density of 100 J/cm2. Histological analysis and macroscopic evaluation were carried out by means of the paper template method. Results: Group G1 showed (53%) of the necrosis area and group G2 showed (11%) necrosis area. Conclusion: The cicatricial acceleration method (MAC®) favored the repair of wounds caused by a 2nd-degree chemical burn, optimizing time and improving quality.

Angioinvasive mucormycosis in burn intensive care units:A case report and review of literature

BACKGROUND Mucormycosis is a rare,rapidly progressive and often fatal fungal infection.The rarity of the condition lends itself to unfamiliarity,delayed treatment,and poor outcomes.Diagnosis of fungal infections early enough to enable appropriate treatment occurs in less than half of affected patients.CASE SUMMARY An 11-year-old girl with a history of 15%total body surface area scald burns involving both lower limbs progressed to develop angioinvasive mucormycosis.This further led to a thrombosis of the right external iliac artery and vein and rapidly progressive necrosis of surrounding soft tissues.She also had dextrocardia and patent foramen ovale.A right hip disarticulation and serial aggressive debridements were performed but she went on to develop systemic sepsis with multisystem involvement and succumbed to the infection.Pathology revealed mucor species with extensive vascular invasion.CONCLUSION This case highlights the importance of maintaining vigilance for mycotic infections and acting appropriately when there are signs of fulminant wound infection.

Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios

Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.

Detection of Burned Areas through Spectral Indices Analysis of Sentinel-2A Satellite Images in the Abokouamékro Wildlife Reserve (Central, Côte D’Ivoire)

In Côte d’Ivoire, the recurring and unregulated use of bushfires, which cause ecological damage, presents a pressing concern for the custodians of protected areas. This study aims to enhance our comprehension of the dynamics of burnt areas within the Abokouamékro Wildlife Reserve (AWR) by employing the analysis of spectral indices derived from satellite imagery. The research methodology began with the calculation of mean indices and their corresponding spectral sub-indices, including NDVI, SAVI, NDWI, NDMI, BAI, NBR, TCW, TCG, and TCB, utilizing data from the Sentinel-2A satellite image dated January 17, 2022. Subsequently, a fuzzy classification model was applied to these various indices and sub-indices, guided by the degree of membership α, with the goal of effectively distinguishing between burned and unburned areas. Following the classification, the accuracies of the classified indices and sub-indices were validated using the coordinates of 100 data points collected within the AWR through GPS technology. The results revealed that the overall accuracy of all indices and sub-indices declines as the degree of membership α decreases from 1 to 0. Among the mean spectral indices, NDVI-mean, SAVI-mean, NDMI-mean exhibited the highest overall accuracies, achieving 97%, 95%, and 90%, respectively. These results closely mirrored those obtained by sub-indices using band 8 (NDVI-B8, SAVI-B8, and NDMI-B8), which yield respective overall accuracies of 93%, 92%, and 89%. At a degree of membership α = 1, the estimated burned areas for the most effective indices encompassed 2144.38 hectares for NDVI-mean, 1932.14 hectares for mean SAVI-mean, and 4947.13 hectares for mean NDMI-mean. A prospective approach involving the amalgamation of these three indices could have the potential to yield improved outcomes. This study could be a substantial contribution to the discrimination of bushfires in Côte d’Ivoire.

Enzymatic debridement shall not modify the global strategy for mass burn events

We read with interest the letter by Surowiecka et al.[1]about early burn wound excision in mass casualty events.We couldn’t agree more with their statement about the benefit of early burn wound excision.Still,we doubt whether applying this strategy to every patient during a mass burn event could be realistic.Of note,while there is an undisputed consensus that early burn wound excision is the gold standard of burn care,what‘early’actually means is still debated.Depending on the authors,the corresponding time limit typically varies from 24 h to a few days[2,3].

Burning rate analysis of laser controlled 5-aminotetrazole propellant

As an innovative propulsion technique, laser augmented chemical propulsion(LACP) seems superior to the traditional ones. However, the corresponding combustion theories have still to be ascertained for LACP. Burning rate of 5-aminotetrazole(5-ATZ) propellant has been studied by testing pressed samples under different combustor pressures and laser powers. Based on micro computed tomography(Micro CT),an advanced thickness-over-time(TOT) method to characterize the regression of the produced nonplanar burning surface is established. Because of a shell structure covering the combustion surface,the burning rate of the implemented 5-ATZ propellant is not constant during laser ablation. Resorting to functional fitting, a new law of non-constant burning including the effect of the observed unique burning surface structures is proposed. Accordingly, applicable combustion conditions of 5-ATZ based propellants have been preliminarily speculated for future research activities.

One-step green method to prepare progressive burning gun propellant through gradient denitration strategy

Gradiently denitrated gun propellant(GDGP)prepared by a“gradient denitration”strategy is obviously superior in progressive burning performance to the traditional deterred gun propellant.Currently,the preparation of GDGP employed a tedious two-step method involving organic solvents,which hinders the large-scale preparation of GDGP.In this paper,GDGP was successfully prepared via a novelty and environmentally friendly one-step method.The obtained samples were characterized by FT-IR,Raman,SEM and XPS.The results showed that the content of nitrate groups gradiently increased from the surface to the core in the surface layer of GDGP and the surface layer of GDGP exhibited a higher compaction than that of raw gun propellant,with a well-preserved nitrocellulose structure.The denitration process enabled the propellant surface with regressive energy density and good progressive burning performance,as confirmed by oxygen bomb and closed bomb test.At the same time,the effects of different solvents on the component loss of propellant were compared.The result showed that water caused the least component loss.Finally,the stability of GDGP was confirmed by methyl-violet test.This work not only provided environmentally friendly,simple and economic preparation of GDGP,but also confirmed the stability of GDGP prepared by this method.

A Rational Design of Metal–Organic Framework Nanozyme with High‑Performance Copper Active Centers for Alleviating Chemical Corneal Burns

Metal–organic frameworks(MOFs)have attracted significant research interest in biomimetic catalysis.However,the modulation of the activity of MOFs by precisely tuning the coordination of metal nodes is still a significant challenge.Inspired by metalloenzymes with well-defined coordination structures,a series of MOFs containing halogen-coordinated copper nodes(Cu-X MOFs,X=Cl,Br,I)are employed to elucidate their structure–activity relationship.Intriguingly,experimental and theoretical results strongly support that precisely tuning the coordination of halogen atoms directly regulates the enzyme-like activities of Cu-X MOFs by influencing the spatial configuration and electronic structure of the Cu active center.The optimal Cu–Cl MOF exhibits excellent superoxide dismutase-like activity with a specific activity one order of magnitude higher than the reported Cu-based nanozymes.More importantly,by performing enzyme-mimicking catalysis,the Cu–Cl MOF nanozyme can significantly scavenge reactive oxygen species and alleviate oxidative stress,thus effectively relieving ocular chemical burns.Mechanistically,the antioxidant and antiapoptotic properties of Cu–Cl MOF are achieved by regulating the NRF2 and JNK or P38 MAPK pathways.Our work provides a novel way to refine MOF nanozymes by directly engineering the coordination microenvironment and,more significantly,demonstrating their potential therapeutic effect in ophthalmic disease.

Effect of CO_(2) dilution on laminar burning velocities,combustion characteristics and NO_(x) emissions of CH_(4)/air mixtures

The laminar combustion characteristics of CH_(4)/air premixed flames with CO_(2) addition are systemically studied.Experimental measurements and numerical simulations of the laminar burning velocity(LBV)are performed in CH_(4)/CO_(2)/Air flames with various CO_(2) doping ratio under equivalence ratios of 1.0–1.4.GRI 3.0 mech and Aramco mech are employed for predicting LBV,adiabatic flame temperature(AFT),important intermediate radicals(CH_(3),H,OH,O)and NO_(x) emissions(NO,NO_(2),N2O),as well as the sensitivity analysis is also conducted.The detail analysis of experiment and simulation reveals that as the CO_(2) addition increases from 0%to 40%,the LBVs and AFTs decrease monotonously.Under the same CO_(2) doping ratio,the LBVs and AFTs increase first and then decrease with the increase of equivalence ratio,and the maximum of LBV is reached at equivalence ratio of 1.05.The mole fraction tendency of important intermediates and NO_(x) with equivalence ratio and CO_(2) doping ratio are similar to the LBVs and AFTs.Reaction H+O_(2)⇔O+OH is found to be responsible for the promotion of the generation of important intermediates and NO_(x) under the equivalence ratios and CO_(2) addition through sensitivity analysis.The sensitivity coefficients of elementary reactions that the increasing of CO_(2) doping ratio promotes or inhibits formation of intermediate radicals and NO_(x) decreases.

Gastrointestinal dysfunction is associated with mortality in severe burn patients:a 10-year retrospective observational study from South China

Background:Data on severe and extensive burns in China are limited,as is data on the prevalence of a range of related gastrointestinal(GI)disorders[such as stress ulcers,delayed defecation,opioid-related bowel immotility,and abdominal compartment syndrome(ACS)].We present a multicentre analysis of coincident GI dysfunction and its effect on burn-related mortality.Methods:This retrospective analysis was conducted on patients with severe[≥20%total burn surface area(TBSA)]and extensive(>50%TBSA or>25%full-thickness TBSA)burns admitted to three university teaching institutions in China between January 1,2011 and December 31,2020.Both 30-and 90-day mortality were assessed by collating demographic data,burn causes,admission TBSA,%full-thickness TBSA,Baux score,Abbreviated Burn Severity Index(ABSI)score,and Sequential Organ Failure Assessment(SOFA)score,shock at admission and the presence of an inhalation injury.GI dysfunction included abdominal distension,nausea/vomiting,diarrhoea/constipation,GI ulcer/haemorrhage,paralytic ileus,feeding intolerance and ACS.Surgeries,length of intensive care unit(ICU)stay,pain control[in morphine milligram equivalents(MME)]and overall length of hospital stay(LOHS)were recorded.Results:We analyzed 328 patients[75.6%male,mean age:(41.6±13.6)years]with a median TBSA of 62.0%(41.0%–80.0%);256(78.0%)patients presented with extensive burns.The 90-day mortality was 23.2%(76/328),with 64(84.2%)of these deaths occurring within 30 d and 25(32.9%)occurring within 7 d.GI dysfunction was experienced by 45.4%of patients and had a significant effect on 90-day mortality[odds ratio(OR)=14.070,95%confidence interval(CI)5.886–38.290,P<0.001].Multivariate analysis showed that GI dysfunction was associated with admission SOFA score and%full-thickness TBSA.Overall,88.2%(67/76)of deceased patients had GI dysfunction[hazard ratio(HR)for death of GI dysfunction=5.951],with a survival advantage for functional disorders(diarrhoea,constipation,or nausea/vomiting)over GI ulcer/haemorrhage(P<0.001).Conclusion:Patients with severe burns have an unfavourable prognosis,as nearly one-fifth died within 90 d.Half of our patients had comorbidities related to GI dysfunction,among which GI ulcers and haemorrhages were independently correlated with 90-day mortality.More attention should be given to severe burn patients with GI dysfunction.

Early burn wound excision in mass casualty events

Dear Editor,The aim of the letter is to stress the need of creating unified recommendations concerning early burn wound excision in cases of mass casualty burns exclusively.There are several triage methods,both for civilian and military circumstances,that govern burn casualty triage and evacuation from the incident site,as well as hospital referral up to 120 h from the disaster.

Transplantation of human induced pluripotent stem cell derived keratinocytes accelerates deep second-degree burn wound healing

BACKGROUND Current evidence shows that human induced pluripotent stem cells(hiPSCs)can effectively differentiate into keratinocytes(KCs),but its effect on skin burn healing has not been reported.AIM To observe the effects of hiPSCs-derived KCs transplantation on skin burn healing in mice and to preliminarily reveal the underlying mechanisms.METHODS An analysis of differentially expressed genes in burn wounds based on GEO datasets GSE140926,and GSE27186 was established.A differentiation medium containing retinoic acid and bone morphogenetic protein 4 was applied to induce hiPSCs to differentiate into KCs.The expression of KCs marker proteins was detected using immunofluorescence staining.A model of a C57BL/6 mouse with deep cutaneous second-degree burn was created,and then phosphate buffered saline(PBS),hiPSCs-KCs,or hiPSCs-KCs with knockdown of COL7A1 were injected around the wound surface.The wound healing,re-epithelialization,engraftment of hiPSCs-KCs into wounds,proinflammatory factor level,and the NF-κB pathway proteins were assessed by hematoxylin-eosin staining,carboxifluorescein diacetate succinimidyl ester(CFSE)fluorescence staining,enzyme linked immunosorbent assay,and Western blotting on days 3,7,and 14 after the injection,respectively.Moreover,the effects of COL7A1 knockdown on the proliferation and migration of hiPSCs-KCs were confirmed by immunohistochemistry,EdU,Transwell,and damage repair assays.RESULTS HiPSCs-KCs could express the hallmark proteins of KCs.COL7A1 was down-regulated in burn wound tissues and highly expressed in hiPSCs-KCs.Transplantation of hiPSCs-KCs into mice with burn wounds resulted in a significant decrease in wound area,an increase in wound re-epithelialization,a decrease in proinflammatory factors content,and an inhibition of NF-κB pathway activation compared to the PBS group.The in vitro assay showed that COL7A1 knockdown could rescue the inhibition of hiPSCs-KCs proliferation and migration,providing further evidence that COL7A1 speeds up burn wound healing by limiting cell proliferation and migration.CONCLUSION In deep,second-degree burn wounds,COL7A1 can promote KC proliferation and migration while also suppressing the inflammatory response.