PROTECTIVE EFFECT OF A NEW SUPEROXIDE-PRODUCING ENZYME COMPLEX FROM RASPBERRY IN RATS WITH THIRD-DEGREE THERMAL BURNS.

Thermal burns are the most common type of burn injuries. Medical treatment for burns is crucial, especially for third-degree burns and when a significant surface area of the body is affected. One of the most pressing issues in modern medicine is the search for new effective means to accelerate the healing of burn wounds. Oxygen radicals play a significant role in maintaining homeostasis, forming the body's resistance to infection, and ensuring the regeneration of organs and tissues. In this study, a superoxide (O2-)-producing enzyme (SPE) from raspberries was applied (topically to the skin, injected under the wound surface, with solution concentrations of 12.75% and 5%) after a third-degree thermal burn to determine its reparative effects on the skin. To assess the condition of the animals that had suffered burn injuries and the healing process, blood parameters were analyzed, and cytogenetic indices of bone marrow from the femur of the animals were studied: mitotic index, number of polyploid cells, and chromosomal aberrations. When analyzing hematological, cytogenetic, and histological parameters, significant differences were found between the «clean burn¼ groups and the groups in which SPE was used in different concentrations and methods of application. The use of SPE in both concentrations contributed to a reduction in the area of burn wounds compared to a «clean burn¼. The survival rate of animals for 30 days (before the end of the experiment) was 100% when using a 12.75% SPE solution and 50% when using a 5% SPE solution. The use of SPE led to significant differences in hematological parameters from the «clean burn¼ group throughout the entire duration of the experiment, showing a tendency to normalize the parameters. Under the influence of the 12.75% SPE solution, there was a tendency toward normalization of the mitotic index, along with a significant reduction in the percentage of polyploid cells and chromosomal aberrations, which may indicate its beneficial effects. This study found that a 12.75% SPE solution derived from raspberries was more effective and had healing properties on third-degree thermal burns, promoting rapid healing of the burn wound.

Sequential management of burn wound healing stages through biointelligence-inspired platelet extracellular vesicle-encapsulated photodynamic diferuloylmethane.

The process of wound healing is a complex, multi-phase phenomenon crucial for optimal tissue regeneration. Traditional drug delivery systems often target specific phases of wound repair, neglecting the dynamic interplay among the stages. This limitation highlights the need for comprehensive delivery systems that cater to the holistic needs of wound healing, enhancing tissue regeneration efficiency. Herein, we explored the utility of platelet-derived extracellular vesicles (pEVs) as carriers for the phototherapeutic diferuloylmethane (DIF), resulting in a formulation termed DIF@pEVs, which is designed to sequentially address the distinct phases of wound healing. Initially, upon exposure to light, administered DIF@pEVs generate photodynamic therapy-derived reactive oxygen species during the early inflammatory phase. This generation of ROS aims to modulate the inflammatory response, induce the protective mechanisms of heat shock proteins, and kickstart the tissue regeneration process. Following this initial phase, the remaining DIF and pEVs persist in promoting tissue repair and regeneration. Ultimately, it reduces inflammation, speeds up the healing process, and promotes vascular and follicular formation in a model of burn wound skin damage, thereby supporting skin regeneration. The deployment of DIF@pEVs represents an advancement in regenerative medicine, providing a precise, versatile approach to fostering regeneration across a wide range of clinical scenarios.

Approaches to scarless burn wound healing: application of 3D printed skin substitutes with dual properties of anti-infection and balancing wound hydration levels.

BACKGROUND: Severe burn wounds face two primary challenges: dysregulated cellular impairment functions following infection and an unbalanced wound hydration microenvironment leading to excessive inflammation and collagen deposition. These results in hypertrophic scar contraction, causing significant deformity and disability in survivors. METHODS: A three-dimensional (3D) printed double-layer hydrogel (DLH) was designed and fabricated to address the problem of scar formation after burn injury. DLH was developed using methacrylated silk fibroin (SFMA) and gelatin methacryloyl (GelMA) for the upper layer, and GelMA and hyaluronic acid methacryloyl (HAMA) for the lower layer. To combat infection, copper-epigallocatechin gallate (Cu-EGCG) was incorporated into the lower layer bioink, collectively referred to as DLS. To balance wound hydration levels, HaCaT cells were additionally encapsulated in the upper layer, designed as DLS/c. FINDINGS: DLH demonstrated suitable porosity, appropriate mechanical properties, and excellent biocompatibility. DLS exhibited potent antimicrobial properties, exerted anti-inflammatory effects by regulating macrophage polarisation, and may enhance angiogenesis through the HIF-1α/VEGF pathway. In the DLS/c group, animal studies showed significant improvements in epidermal formation, barrier function, and epidermal hydration, accompanied by reduced inflammation. In addition, Masson's trichrome and Sirius red staining revealed that the structure and ratio of dermal collagen in DLS/c resembled that of normal skin, indicating considerable potential for scarless wound healing. INTERPRETATION: This biomimetic matrix shows promise in addressing the challenges of burn wounds and aiming for scarless repair, with benefits such as anti-infection, epidermal hydration, biological induction, and optimised topological properties. FUNDING: Shown in Acknowledgements.

Hiding the evidence: Preliminary investigation of heat-induced alterations to pre-existing saw mark trauma.

Dismemberment and subsequent burning are common methods employed in an attempt to conceal or destroy evidence. While kerf characteristics can be utilised to identify tool(s) used for dismemberment, further research is necessary to assess the effect of burning on these characteristics. In this study, a back (tenon) saw (13 teeth per inch) was used to manually inflict trauma on Ovis aries de-fleshed femur bones (n = 18). Three different cut marks (shallow false start, incomplete cut and complete transection) were made on the mid-shaft of each bone. Subsequently, the bones were burned for 20 minutes in a muffle furnace. Three burn temperatures were assessed: 400 °C, 600 °C and 800 °C. Saw mark characteristics of each cut type were assessed and compared pre- and post-burning. All pre-existing trauma was recognisable post-burning; however, metric and morphological alterations were apparent. An increase in kerf width was observed at 600 °C in false start lesions and 800 °C in incomplete cuts. Breakaway spur thickness decreased post-burning (at 400 °C and 800 °C) but length was not significantly affected. Mean inter-striation distance decreased post burning at all temperature groups. Saw marks were distinguishable from heat-related fractures across all temperature groups. One false start lesion was obliterated at 800 °C. Exit chipping, pull-out striae as well as striation regularity appeared to be more enhanced after heat exposure. These alterations indicate a temperature-dependent impact on these characteristics. Further research is necessary to assess the role of burn duration.

IL-8 Induces Neutrophil Extracellular Trap Formation in Severe Thermal Injury.

Neutrophil extracellular traps (NETs) have a dual role in the innate immune response to thermal injuries. NETs provide an early line of defence against infection. However, excessive NETosis can mediate the pathogenesis of immunothrombosis, disseminated intravascular coagulation (DIC) and multiple organ failure (MOF) in sepsis. Recent studies suggest that high interleukin-8 (IL-8) levels in intensive care unit (ICU) patients significantly contribute to excessive NET generation. This study aimed to determine whether IL-8 also mediates NET generation in patients with severe thermal injuries. IL-8 levels were measured in serum samples from thermally injured patients with ≥15% of the total body surface area (TBSA) and healthy controls (HC). Ex vivo NET generation was also investigated by treating isolated neutrophils with serum from thermal injured patients or normal serum with and without IL-8 and anti-IL-8 antibodies. IL-8 levels were significantly increased compared to HC on days 3 and 5 (p < 0.05) following thermal injury. IL-8 levels were also significantly increased at day 5 in septic versus non-septic patients (p < 0.001). IL-8 levels were also increased in patients who developed sepsis compared to HC at days 3, 5 and 7 (p < 0.001), day 10 (p < 0.05) and days 12 and 14 (p < 0.01). Serum containing either low, medium or high levels of IL-8 was shown to induce ex vivo NETosis in an IL-8-dependent manner. Furthermore, the inhibition of DNase activity in serum increased the NET-inducing activity of IL-8 in vitro by preventing NET degradation. IL-8 is a major contributor to NET formation in severe thermal injury and is increased in patients who develop sepsis. We confirmed that DNase is an important regulator of NET degradation but also a potential confounder within assays that measure serum-induced ex vivo NETosis.

The effect of acellular scaffold loaded with Wharton's jelly-derived stem cells and mineral pitch on healing of burn model in rat.

Severe burns often result in an exacerbated inflammatory response, which can contribute to further injury. This inflammatory response may lead to an increased risk of infection, multiple organ failure, and death. This study aimed to investigate the potential of reducing inflammation to enhance burn wound healing in rats using ovine's small intestinal submucosa as a carrier for Wharton's jelly mesenchymal stem cells (WJ-MSCs) and Mineral Pitch (MP). A rat burn model was developed, and the animals were divided into four groups: control group: burn, placebo group: scaffold-treated burn, cell experimental group: WJ-MSCs seeded scaffold-treated burn, and cell and MP experimental group: scaffolds loaded with WJ-MSCs and MP-treated burn. After treating the wounds in the relevant groups and sampling them on days 5, 14 and 21, histological and pathological parameters, and the expression of genes involved in angiogenesis and epithelialization were evaluated. The study results revealed several findings in the burn wounds. These included changes in mast cell populations, a decrease in inflammatory neutrophils and lymphocytes, an increase in fibroblasts and blood vessels, and upregulation of angiogenesis and epithelialization genes. These changes collectively contributed to enhanced wound healing in cell and MP experimental group compared to the other groups. The findings suggest that scaffolds loaded with Wharton's jelly-derived stem cells and MP can serve as engineered tools to modulate inflammatory conditions during the burn wound healing process. These interventions can improve burn wound management and promote better outcomes.

Perioperative research into memory (PRiMe), part 2: Adult burns intensive care patients show altered structure and function of the default mode network.

BACKGROUND: Long-term cognitive impairment (LTCI) is experienced by up to two thirds of patients discharged from burns intensive care units (BICUs), however little is known about its neurobiological basis. This study investigated if patients previously admitted to BICU showed structural and functional MRI changes of the Default Mode Network (DMN). METHODS: Fifteen patients previously admitted to BICU with a significant burns injury, and 15 matched volunteers, underwent structural and functional MRI scans. Functional connectivity, fractional anisotropy and cortical thickness of the main DMN subdivisions (anterior DMN (aDMN), posterior DMN (pDMN) and right (rTPJ) and left (lTPJ) temporo-parietal junctions) were compared between patients and volunteers, with differences correlated against cognitive performance. RESULTS: Functional connectivity between rTPJ and pDMN (t = 2.91, p = 0.011) and between rTPJ and lTPJ (t = 3.18, p = 0.008) was lower in patients compared to volunteers. Functional connectivity between rTPJ and pDMN correlated with cognitive performance (r2 =0.33, p < 0.001). Mean fractional anisotropy of rTPJ (t = 2.70, p = 0.008) and lTPJ (T = 2.39, p = 0.015) was lower in patients but there was no difference in cortical thickness. CONCLUSIONS: Patients previously admitted to BICU show structural and functional disruption of the DMN. Since functional changes correlate with cognitive performance, this should direct further research into intensive-care-related cognitive impairment.

Superoxide dismutase-contained solid lipid nanoparticles: Formulation development and In-vivo evaluation for second-degree burn wound healing in rats.

INTRODUCTION: Superoxide dismutase (SOD), a natural enzyme with high antioxidant activity, reduces injury and accelerates wound healing by scavenging superoxide radicals. This enzyme plays an important role in cellular defense against oxidative stress such as burn injury. The aim of this study was to load SOD into solid lipid nanoparticles for the treatment of rat burn wounds. METHODS: Solid lipid nanoparticles were prepared by Solvent Emulsification Diffusion method and evaluated for particle size, enzyme activity and enzyme entrapment efficiency. Twenty-seven rats in 3 different groups were induced with deep second-degree burns and then treated with SOD-loaded solid lipid nanoparticles, solid lipid nanoparticles without enzyme, or SOD solution. After the treatment period, the wounds were evaluated macroscopically for the area of healing and microscopically for indices of re-epithelialization, granulation tissue and angiogenesis. RESULTS: The optimized SOD-loaded solid lipid nanoparticles showed a particle size of 35-85 ± 2.41 nm, 78.4 ± 4.31 % entrapment efficiency and 90 % initial enzyme activity. Macroscopic examination showed that the best recovery rate belonged to the solid lipid nanoparticle group. Pathological studies also showed that angiogenesis and granulation tissue were significantly better in this group. Compared to the other two groups, SOD-loaded solid lipid nanoparticles showed a significant improvement in pathological factors, particularly angiogenesis and granulation tissue, as well as a faster reduction in the number of inflammatory cells. CONCLUSION: Based on this study, solid lipid nanoparticles could be used as an effective delivery system for SOD in the treatment of second-degree burns.

Sodium valproate inhibited apoptosis in lethally scalded rat cardiomyocytes by regulating hypoxia-inducible factor-1α expression.

This study assessed the inhibitory effect of sodium valproate (VPA) on apoptosis of cardiomyocytes in lethally scalded rats. The model of a 50% total body surface area (TBSA) third-degree full-thickness scald was produced, 48 male SD rats were randomly divided into three groups (n = 16), the sham group and the scald group were given an intraperitoneal injection of 0.25ml of saline, the scald +VPA group was given an intraperitoneal injection of VPA (300 mg/kg) after scalded, Each group was subdivided into two subgroups (n=8) according to the two observation time points of 3h and 6h after scald. Apoptotic cardiomyocytes were observed, and myocardial tissue levels of nitric oxide (NO), cysteine protease-3 (caspase-3) activity, hypoxia-inducible factor-1α (HIF-1α), inducible nitric oxide synthase (iNOS), BCL2/adenovirus E1B interacting protein 3 (BNIP3) and caspase-3 protein were measured. Compared with sham scald group, severe scald elevated CK-MB, cardiomyocyte apoptosis rate, caspase-3 activity and protein levels, NO content, and HIF-1α signalling pathway proteins; whereas VPA decreased CK-MB, cardiomyocyte apoptosis rate and inhibited HIF-1α signalling pathway protein expression. In conclusion, these results suggested that VPA inhibited early cardiomyocyte apoptosis and attenuated myocardial injury in lethally scalded rats, which may be related to the regulation of the HIF-1α signalling pathway.

Red-light-excited TiO2/Bi2S3 heterojunction nanotubes and photoelectric hydrogels mediate epidermal-neural network reconstruction in deep burns.

Inspired by the strong light absorption of carbon nanotubes, we propose a fabrication approach involving one-dimensional TiO2/Bi2S3 QDs nanotubes (TBNTs) with visible red-light excitable photoelectric properties. By integrating the construction of heterojunctions, quantum confinement effects, and morphological modifications, the photocurrent reached 9.22 µA/cm2 which is 66 times greater than that of TiO2 nanotubes (TNTs). Then, a red light-responsive photoelectroactive hydrogel dressing (TBCHA) was developed by embedding TBNTs into a collagen/hyaluronic acid-based biomimetic extracellular matrix hydrogel with good biocompatibility, aiming to promote wound healing and skin function restoration. This approach is primarily grounded in the recognized significance of electrical stimulation in modulating nerve function and immune responses. Severe burns are often accompanied by extensive damage to epithelial-neural networks, leading to a loss of excitatory function and difficulty in spontaneous healing, while conventional dressings inadequately address the critical need for nerve reinnervation. Furthermore, we highlight the remarkable ability of the TBCHA photoelectric hydrogel to promote the reinnervation of nerve endings, facilitate the repair of skin substructures, and modulate immune responses in a deep burn model. This hydrogel not only underpins wound closure and collagen synthesis but also advances vascular reformation, immune modulation, and neural restoration. This photoelectric-based therapy offers a robust solution for the comprehensive repair of deep burns and functional tissue regeneration. STATEMENT OF SIGNIFICANCE: We explore the fabrication of 1D TiO2/Bi2S3 nanotubes with visible red-light excitability and high photoelectric conversion properties. By integrating heterojunctions, quantum absorption effects, and morphological modifications, the photocurrent of TiO2/Bi2S3 nanotubes could reach 9.22 µA/cm², which is 66 times greater than that of TiO2 nanotubes under 625 nm illumination. The efficient red-light excitability solves the problem of poor biosafety and low tissue penetration caused by shortwave excitation. Furthermore, we highlight the remarkable ability of the TiO2/Bi2S3 nanotubes integrated photoelectric hydrogel in promoting the reinnervation of nerve endings and modulating immune responses. This work proposes an emerging therapeutic strategy of remote, passive electrical stimulation, offering a robust boost for repairing deep burn wounds.

Stem Cell-Derived Nanovesicles Embedded in Dual-Layered Hydrogel for Programmed ROS Regulation and Comprehensive Tissue Regeneration in Burn Wound Healing.

Burn wounds often bring high risks of delayed healing process and even death. Reactive oxygen species (ROS) play a crucial role in burn wound repair. However, the dynamic process in wound healing requires both the generation of ROS to inhibit bacteria and the subsequent reduction of ROS levels to initiate and promote tissue regeneration, which calls for a more intelligent ROS regulation dressing system. Hence, a dual-layered hydrogel (Dual-Gel) tailored to the process of burn wound repair is designed: the inner layer hydrogel (Gel 2) first responds to bacterial hyaluronidase (Hyal) to deliver aggregation-induced emission photosensitizer functionalized adipose-derived stem cell nanovesicles, which generate ROS upon light irradiation to eliminate bacteria; then the outer layer hydrogel (Gel 1) continuously starts a long-lasting consumption of excess ROS at the wound site to accelerate tissue regeneration. Simultaneously, the stem cell nanovesicles trapped in the burns wound also provide nutrients and mobilize neighboring tissues to thoroughly assist in inflammation regulation, cell proliferation, migration, and angiogenesis. In summary, this study develops an intelligent treatment approach on burn wounds by programmatically regulating ROS and facilitating comprehensive wound tissue repair.

The effects of Anchusa azurea methanolic extract on burn wound healing: Histological, antioxidant, and anti-inflammatory evaluation.

Anchusa azurea one of the medicinal plants that has been traditionally used for treat burn wounds. However, the traditional claim that A.azurea can hasten burn wound healing has not been supported by scientific studies. This experiment used a male Wistar rats model to investigate the activity of A. azurea aerial parts methanolic extract in burn wound healing. To determine their ability to help in healing burn wounds in rat models, the active components of the aerial parts of A. azurea were extracted with 80% methanol, then, 1% and 10% ointments were prepared from the extract, and applied topically. The LCMS chromatography of A. azurea plant extract showed different active ingredients, including phenolic compounds, flavonoids, fatty acids, and others. The plant extract's investigated as anti-inflammatory, antioxidant, and histological effects on the burn wound healing process. The results showed a significant (p-value < 0.025) rate of burn wound healing with 78.6% and 84.8% contraction, respectively using 1% and 10% (w/w) extract ointments after 12 days. These results were corroborated by histological observations such as collagen deposition, re-epithelialization, and repair of the remaining skin tissues without any sign of cutaneous toxicity. The plant extract showed significant (p-value < 0.025) antioxidant effect at the highest tested dose of 500 µg/mL, scavenging 89.78% of the DPPH with an IC50 of 213.6 µg/mL. These results confirmed by histological changes observations of collagen deposition, re-epithelialization, and reformation of remaining skin tissues without any signs of dermal toxicity. The plant extract exhibited significant (p-value < 0.025) level of antioxidant agents, by scavenging 89.78% of the DPPH at 500 µg/mL with IC50 of 213.6 µg/mL. Additionally, all pro-inflammatory cytokines examined, including IL-6 and IL-10, the results exhibited reduction in IL-6 level and increase IL-10 level. The aerial extract of the A. azurea plant revealed a wealth of several significant active ingredients, including phenolic compounds, flavonoids, fatty acids, and others, suggesting the potential for anti-inflammatory, burn wound-healing, and antioxidant medications. These findings can open an avenue to find new therapeutics for burn wounds healing, anti-inflammatory and antioxidant properties.

Malignant melanoma arising in a burn scar.

Secondary malignancies are rare but devastating complications of longstanding burn scars. Squamous cell carcinoma is the most common, followed by basal cell carcinoma and melanomas. There are fewer than 50 total reported cases of malignant melanomas arising in burn scars. We report a case of malignant melanoma arising within a longstanding burn scar confirmed by histology, FISH, and PRAME staining to further characterize melanomas arising in burn scars and to illustrate the diagnostic challenges they present.

Thermal damage to the skin from 8.2 and 95 GHz microwave exposures in swine.

A study of burn thresholds from superficially penetrating radio-frequency (RF) energy at 8.2 and 95 GHz for swine skin was conducted. The study determined the thresholds for superficial, partial-thickness, and full-thickness burn severities after 5 seconds of exposure at power densities of 4-30 W/cm2and 2-15 W/cm2at 8.2 and 95 GHz, respectively. There were significant differences in he burn thresholds at the different severities between the two frequencies due to the large difference in energy penetration depths. Biopsies were collected from each burn site at 1, 24, 72, and 168 hr post exposure. Each sample was assessed by a burn pathologist against 20 histological factors to characterize the damage resulting from these RF overexposures. A one-dimensional, layered digital phantom that utilized realistic values for dielectric and thermal properties was used to explain some observed thresholds. The results of the heating and cooling response of the animal model and histology scores of each exposure are provided to enhance future efforts at simulation of RF overexposures and to establish damage thresholds.

α-ketoglutarate preconditioning extends the survival of engrafted adipose-derived mesenchymal stem cells to accelerate healing of burn wounds.

The application of adipose-derived stem cells (ADSCs) in treating hard-to-heal wounds has been widely accepted, while the short-term survival rate remains an obstacle in stem cell therapy. The aim of this study is to investigate the effect of preconditioning ADSCs with α-ketoglutarate (α-KG) on the healing of acid burn wounds and cell survival within wounds. Preconditioning of ADSCs was performed by treating cells at passage 3 with 3.5 mM DM-αKG for 24 h. Proliferation and migration of ADSCs was examined. An acid burn wound was created on the dorsal skin of mice. Cell suspension of ADSCs (2 × 106 cells/ml), either pre-treated with α-KG or not, was injected subcutaneously around the margin of wound. At 1,4,7,10,14 days after injection, the percentage of wound closure was evaluated. Expression of pro-angiogenic factors, matrix molecules and HIF1-α in pretreated ADSCs or in wounds was evaluated by qRT-PCR and immunohistochemistry staining, respectively. The survival rate of DiO-labelled ADSCs was determined with the in vivo bioluminescent imaging system. Treating with α-KG induced an enhancement in migration of ADSCs, while their proliferation was not affected. Expression of Vegf and Fgf-2 was significantly increased. With injection of pretreated ADSCs, healing of wounds was remarkably accelerated, along with increased ECM deposition and microvessel density. Moreover, pretreatment with α-KG resulted a prolonged survival of engrafted ADSCs was observed. Expression of HIF-1α was significantly increased in ADSCs treated with α-KG and in wounds injected with preconditioned ADSCs. Our results revealed that healing of acid burn wound was accelerated with administration of ADSCs pretreated with α-KG, which induced elevated expression of HIF-1α and prolonged survival of engrafted stem cells.

Inhibition of Let-7b-5p maturation by LIN28A promotes thermal skin damage repair after burn injury.

Burn injuries, especially severe ones, result in direct and indirect thermal damage to skin tissues, with a complex and slow wound healing process. Improper treatment can induce sustained inflammatory responses, causing systemic damage. Lin28A, a highly conserved RNA binding protein, was found to exert a significant effect on cell proliferation and wound repair. Lin28A exerts the functions through inhibiting the maturation of the let-7 family miRNAs. Herein, the roles of Lin28A and let-7b in thermal injury repair were investigated using a mouse thermal injury model and a human skin fibroblast (HSF) model for thermal injuries. Lin28A could inhibit the maturation of let-7b, thus participating in skin repair after burns. In the animal model, Lin28A was highly expressed after thermal injury. In the HSF model for thermal injuries, downregulation of Lin28A inhibited the proliferation, migration, and extracellular matrix (ECM) generation of fibroblasts. When let-7b was knocked down in HSFs, the impacts on fibroblast functions caused by downregulation of Lin28A were partially reversed. Moreover, let-7b overexpression might significantly attenuate the promotive effects of Lin28A upon thermal injury repair. Finally, AKT2 and IGF1R were the let-7b target genes within cells. These findings reveal that Lin28A might promote thermal injury repair in burn-injured skin by inhibiting the maturation of let-7b and improving HSF viability and functions, thus illustrating the critical effect of let-7b on burn wound healing and providing new therapeutic targets and strategies for burn treatment.

Wound healing effect of nutmeg (Myristica fragrans) cream on second-degree burn in animal model.

Second-degree burn, the most common among burn degrees, underscores the importance of timely and proper treatment in influencing prognosis. Nutmeg (Myristica fragrans), renowned for its potent antibacterial and antifungal properties, also serves as an effective antiseptic for open wounds. The aim of this study was to identify the phytochemical constituents of nutmeg essential oil and analyze the wound healing effect of nutmeg cream on second-degree burns in an animal model. An experimental study with a completed randomized design was conducted on Rattus norvegicus strain Wistar rats with second-degree burn. This study had four groups and each group consisting of four rats: B (burn-treated base cream), B+N (burn-treated 3% nutmeg cream), B+SSD (burn-treated silver sulfadiazine (BSS)), and B+N+SSD (burn-treated 3% nutmeg cream and SSD in a 1:1 ratio). The phytochemical analysis of nutmeg essential oil was conducted by gas chromatography and mass spectroscopy (GC-MS). The burn diameter and burn wound healing percentage were measured from day 0 to 18. One-way ANOVA followed by post hoc analysis using the least significant difference (LSD) was employed to analysis the effect. The phytochemical analysis of nutmeg essential oil found that myristicin, terpinene-4-ol, terpinene, safrole and terpinolene were the most abundant putative compounds in nutmeg essential oil. On day 0, the average burn wound diameters were 1.4 cm in all groups and increases were observed in all groups on day 3. The wound diameter decreased until day 18 with the smallest burn wound diameter was found in the B+N group (0.86±0.37 cm), followed by B+SSD (0.93±0.29 cm). The B+SSD group exhibited the highest percentage of burn wound healing (56.80±14.05%), which was significantly different from the base cream (p<0.05). The percentage of burn wound healing in rats given 3% nutmeg cream was 41.88±13.81%, suggesting that nutmeg cream could promote burn wound healing in rats induced by second-degree burns.

Recombinant human growth hormone promotes wound angiogenesis in burned mice through the ERK signaling pathway.

Burns are the most severe type of trauma, and the resulting ischemia and hypoxia damage can promote the dysfunction and even failure of tissues and organs throughout the body, endangering patients' life safety. Recombinant human growth hormone (rhGH) has the functions of promoting protein synthesis to reverse negative nitrogen balance, accelerating wound healing, and improving immune function, which is widely used in the treatment of burns. However, the exact mechanism and pathway of rhGH's action is not yet fully understood. In this study, we observed the wound repair effect of recombinant human growth hormone (rhGH) on burned mice and further analyzed the mechanism of action, which can provide more comprehensive reference opinions for clinical practice. First, by establishing a burn mouse model and and intervening with different doses of rhGH, we found that the wound healing capacity of mice was significantly enhanced and the inflammatory and oxidative stress responses were obviously alleviated, confirming the excellent promotion of wound repair and anti-inflammatory and antioxidant effects of rhGH. Subsequently, we found that the expression of p-ERK1/2/ERK1/2, EGF, TGF-ß, and VEGF proteins was elevated in the traumatic tissues of mice after rhGH intervention, suggesting that the pathway of action of rhGH might be related to the activation of ERK pathway to promote the regeneration of traumatic capillaries.

In vitro and in vivo burn healing study of standardized propolis: Unveiling its antibacterial, antioxidant and anti-inflammatory actions in relation to its phytochemical profiling.

BACKGROUND: Natural propolis has been used since decades owing to its broad-spectrum activities. Burn injuries are a global health problem with negative impacts on communities. Bacterial infections usually accompany burns, which demand implementation of antibiotics. Antibiotics abuse led to emergence of microbial drug resistance resulting in poor treatment outcomes. In such instances, the promising alternative would be natural antimicrobials such as propolis. OBJECTIVE: Full chemical profiling of propolis and evaluation of in vitro antibacterial, antioxidant and anti-inflammatory activities as well as in vivo burn healing properties. METHODS: Chemical profiling of propolis was performed using Liquid chromatography (UHPLC/MS-PDA and HPLC-PDA). In vitro assessment was done using Disc Diffusion susceptibility test against Staphylococcus aureus and infected burn wound mice model was used for in vivo assessment. In vitro antioxidant properties of propolis were assessed using DPPH, ABTS and FRAP techniques. The anti-inflammatory effect of propolis was assessed against lipopolysaccharide/interferon-gamma mediated inflammation. RESULTS: UHPLC/MS-PDA results revealed identification of 71 phytochemicals, mainly flavonoids. Upon flavonoids quantification (HPLC-PDA), Pinocembrin, chrysin and galangin recorded high content 21.58±0.84, 22.73±0.68 and 14.26±0.70 mg/g hydroalcoholic propolis extract, respectively. Propolis showed concentration dependent antibacterial activity in vitro and in vivo burn healing via wound diameter reduction and histopathological analysis without signs of skin irritation in rabbits nor sensitization in guinea pigs. Propolis showed promising antioxidant IC50 values 46.52±1.25 and 11.74±0.26 µg/mL whereas FRAP result was 445.29±29.9 µM TE/mg. Anti-inflammatory experiment results showed significant increase of Toll-like receptor 4 (TLR4), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) mRNA levels. Nitric oxide and iNOS were markedly increased in Griess assay and western blot respectively. However, upon testing propolis against LPS/IFN-γ-mediated inflammation, TLR4, IL-6 and TNF-α expression were downregulated at transcriptional and post-transcriptional levels. CONCLUSION: Propolis proved to be a promising natural burn healing agent through its antibacterial, antioxidant and anti-inflammatory activities.