Assessment of dermal wound healing and in vitro antioxidant properties of Avena sativa L.

Avena sativa L. (Poaceae) has been reported to have traditional utilization against skin diseases and inflammation. Therefore, in this study, the n-hexane, ethyl acetate, ethanol, and water extracts of A. sativa were investigated for their wound healing and antioxidant activities. Total phenol and flavonoid contents of the extracts were established spectrophotometrically. For the wound healing activity, linear incision and circular excision models on rats and mice were evaluated with a standard ointment Madecassol^®. Antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferrous ion-chelating, and ferric-reducing antioxidant power (FRAP) assays. Significant wound healing activity was observed with the ointment formulation of the ethanol extract at 1% concentration. The histopathological examination results also supported the outcome of both linear incision and circular excision wound models. All of the extracts exerted low antioxidant activity in the applied assays. The present study provides a scientific evidence for the traditional usage of A. sativa in the management of wound healing.     

Topical formulations of water-soluble chitin as a wound healing assistant

Water-soluble chitin (WSC) was prepared by carefully deacetylating chitins to about 50% of N-acetyl content. Topical formulations based on WSC were prepared and their effects on wound healing were evaluated on a rabbit ear model. Full-thickness, open skin wounds were made on the ears of rabbits and WSC ointments were embedded in the open wounds. The application of WSC ointments significantly accelerated wound healing and wound contraction. The areas of epithelialization and granulation tissues in WSC ointment group are remarkably larger than those in control group (no treatment) and in placebo group (treated with ointment-base materials). A large number of grown granulation tissues including dense fibroblast deposition were observed under the thickened epithelium of the wound treated with WSC ointments. The number of inflammatory cells in WSC ointment group was significantly decreased compared with those in control and placebo groups, indicating that WSC would give low stimuli to wounds and prevent excessive scar formation. Neovascularization was the most prominent in WSC ointment group. Wound contraction in WSC ointment group was much larger than those in control and placebo groups. Overall results demonstrate that the topical formulation based on WSC is considered to become an excellent dressing as a wound healing assistant.     

Oral administration of skin gelatin isolated from Chum salmon (Oncorhynchus keta) enhances wound healing in diabetic rats

Care for diabetic wounds remains a significant clinical problem. The present study was aimed at investigating the effect of skin gelatin from Chum Salmon on defective wound repair in the skin of diabetic rats. Full-thickness excisional skin wounds were made in 48 rats, of which 32 were diabetes. The diabetic rats were orally treated daily for 14 days with skin gelatin from Chum Salmon (2 g/kg) or its vehicle. Sixteen non-diabetic control rats received the same amount of water as vehicle-treated non-diabetic rats. Rats were killed to assess the rate of wound closure, microvessel density (MVD), vascular endothelial growth factor (VEGF), hydroxyproline (HP) contents in wound tissues and nitrate in plasma and wound tissue at 7 and 14 days after wounding. Skin gelatin-treated diabetic rats showed a better wound closure, increased MVD, VEGF, hydroxyproline and NO contents and a reduced extent of inflammatory response. All parameters were significant (P < 0.05) in comparison to vehicle-treated diabetic group. In light of our finding that skin gelatin of Chum Salmon promotes skin wound repair in diabetic rats, we propose that oral administration of Chum Salmon skin gelatin might be a beneficial method for treating wound disorders associated with diabetes.     

SPI/PEO blended electrospun martrix for wound healing

Conventional textile based wound dressing materials are cost effective and highly absorbent, but when used alone fails to provide optimal wound healing conditions like homeostasis, non-adherence, maintenance of a moist wound bed, etc. Electrospun polymer web meets the requirements outlined for wound healing, by their microfibrous structures provide suitable environment for wound healing apart from the function of polymers. In this study, blends of soy protein isolate (SPI) and poly(ethylene oxide) (PEO) nano fiber web was prepared by electro spinning process. The developed blended nano fiber web was subjected to SEM, FTIR to evaluate fiber size and functional properties respectively. The Moisture vapour transmission rate (MVTR) result shows the blended electrospun web gives suitable mosit environment over wound bed such as the MVTR is 2994 g/m²/day. The blended electrospun web gives positive result on antimicrobial activity. The effect of SPI/PEO blended electrospun web on wound healing was experimented with female wistar rats and the blended electrospun web shows excellent result on wound healing by the growth of new epithelium without any significant adverse reaction. Forming of SPI/PEO electrospun fiber was fulfilled many critical elements desirable in a wound material.     

Influence of vine senescence and storage on wound healing of Russet Burbank tubers

Potato (Solanum tuberosum L. cv. Russet Burbank) tubers were harvested weekly over a 6 week period from non-water-stressed and water-stressed plants. Discs were cut from fresh tubers and from tubers stored for 10 days at 4°C to determine their wound healing ability as evaluated by disc resistance to water loss. Neither harvest date nor water status significantly influenced wound healing while storage significantly increased wound healing ability. Enhanced wound healing associated with storage was accompanied by reduced variability of disc resistance to water loss and increased levels of suberin as reflected by the diol and alcohol components. This work suggests that plant senescence and harvest date are not good indicators of the potential wound healing ability of tubers. Physiological evidence is presented to support the practice of short periods of storage following harvest to improve tuber wound healing ability and thereby reduce shipping and handling losses due to injury.     

Temporal variation in the recovery from impairment in adriamycin-induced wound healing in rats

Background  

An adriamycin-induced impairment of wound healing has been demonstrated experimentally in rats. The purpose of this study is to investigate a possible temporal variation in recovery from the impairment of wound healing caused by adriamycin administration.     

Porometric measurements indicate wound severity and tuber maturity affect the early stages of wound-healing

We demonstrated that porometrically derived wound-healing profiles of whole tubers were greatly affected by the depth or severity of the wound. A rapid decrease in water vapor conductance was detected during the first 24 h of healing after mature, whole tubers were wounded by tangentially cutting into the cortex. The rapid decline in vapor conductance, indicating deposition of soluble waxes, was not concurrent with detectable deposition of polymeric phenolic or polymeric aliphatic components of the suberin polyester; instead these polymerized components were detected after vapor conductance decreased by approximately 80% and was nearly stable. The rate of decline of vapor conductance of wound-healing tubers was hormonally hastened with abscisic acid treatments. Although deeper tangential wounds (3.0 mm) had slower initial rates of wound-healing than did shallow wounds (0.75 mm) through tuber growth and maturation, the ability to wound-heal more rapidly increased as the tubers matured in the field. The vapor conductance of wound healing tubers declined in a log-linear fashion during the first 1 to 3 days after wounding depending upon tuber maturity and genotype.     

Surface modification of silk fibroin nanofibrous mat with dextran for wound dressing

In this study, we examined the effects of a dextran-modified silk fibroin nanofibrous mat (D-SFNM) on wound healing. To increase the hydrophilicity of silk fibroin (SF), the SF nanofibrous mat (SFNM) was modified with oxidized dextran. The D-SFNM absorbed water faster than the SFNM, and the swelling ratio was increased by approximately 80 % compared with the SFNM. An in vitro cell (NIH3T3) test revealed that fewer cells attached to the D-SFNM than the SFNM, but the proliferation of cells was not significantly affected by the presence of dextran. An in vivo wound healing test with mice indicated that the D-SFNM resulted in a good wound recovery effect similar to a commercial wound dressing material. The increased hydrophilicity of the D-SFNM might balance the moist environment at the wound site, which improves the wound healing compared with the SFNM.     

Solution blowing of chitosan/PLA/PEG hydrogel nanofibers for wound dressing

In this study, a kind of hydrogel nanofibers were successfully fabricated via solution blowing of chitosan (CS) and polylactic acid (PLA) solutions mixed with various contents of polyethylene glycol (PEG) to offer hydration. The nanofibers with PEG content varying were average 341-376 nm in diameter with smooth surface and distributed randomly forming three-dimension (3D) mats. Glutaraldehyde (GA) vapor was then applied to impart stability, and the cross-linking reaction mainly occurred between GA and hydroxyl groups which was confirmed by XPS. The hydrogel nanofibers showed quick absorption behavior, high equilibrate water absorption and good air permeability which could help the mats absorbing excess exudates, creating a moist wound healing environment and oxygen exchanging in wound healing. The mats also exhibited good antibacterial activities against E. coil. The combination advantages of nanofibers mats and hydrogel will help it find promising application in wound healing.     

Designing double-layered nanofibrous membranes as a wound dressing material

New generation wound dressings require the criteria that both bioactive and conventional wound dressing materials can recompense the fundamental properties like defense of wound from microbial invasion, dehydration during the wound care duration and mimic the healing process. In this study, functional double-layered nanofibrous composite membranes were fabricated via electrospinning method. The matrices consist of a sheet of ampicillin loaded poly(2-hydroxylethyl methacrylate/polyacrylic acid (pHEMA/pAA) nanofibers on the upper side (first layer: pH sensitive antibacterial barrier) and a sheet of poly(ε-caprolactone) (PCL)/gelatin nanofibers (second layer: bioactive part). Ampicillin was successfully incorporated to double-layered matrices which greatly changed the mechanical properties, biodegradability and water uptake ratios (up to 4 fold higher values). The success of the antimicrobial activity of ampicillin on Staphylococcus aureus and Escherichia coli was indicated by the inhibition zone test. pH sensitivity was confirmed by the swelling and ampicillin release studies by shifting pH value to basic environment. Thus, double-layered pHEMA-pAA nanofibers suggest as a potential wound dressing material for its pH sensitive drug delivery ability and its bioactive part.     

Water loss from potato tuber discs: a method for assessing wound healing

Summary A rapid and simple method for assessing wound healing in dises of potato tuber tissue has been developed. The rate of water loss is measured when batches of six dises are briefly exposed in a stream of air. The rate of water loss shows little change during the early stages of wound healing but decreases rapidly later.     

Naringin-loaded Poly(ε-caprolactone)/Gelatin Electrospun Mat as a Potential Wound Dressing: In vitro and In vivo Evaluation

In the present study, naringin, a flavonoid isolated from the grape and citrus fruit species, was incorporated with poly(ε-caprolactone)/gelatin composite mats in order to develop a potential wound dressing. The composite mats were prepared by electrospinning of poly(ε-caprolactone)/gelatin (1:1 (w/w)) solution incorporated with 1.50 %, 3 % and 6 % (w/w) of naringin. The electrospun mats were evaluated regarding their morphology, contact angle, water-uptake capacity, water vapor transmission rate, tensile properties, drug release, cellular response and in vivo wound healing activity. The study showed that after 2 weeks, the full-thickness excisional wounds of Wistar rats treated with the naringin-loaded dressings achieved a wound closure of higher than 94 % and the dressing containing 6 % (w/w) naringin had almost 100 % wound closure. The sterile gauze, as the control group, showed nearly 86 % of wound closure after this period of time. Our results provided evidence that supports the possible applicability of naringin-loaded wound dressing for successful wound treatment.     

Fabrication of electropsun PLGA and small intestine submucosa-blended nanofibrous membranes and their biocompatibility for wound healing

In recent decades, tremendous research has focused on the production of nanoscale fibers using synthetic polymers, with the goal of fabricating nanofibrous scaffolds for wound healing. However, the hydrophobicity of such polymers typically hinders attachment and proliferation of the cells. In this study, we combined poly-d,l-lactide-co-glycolide (PLGA) and small intestine submucosa (SIS) to fabricate blended nanofibers for wound healing by electrospinning. PLGA and SIS were dissolved in 1,1,1,3,3,3-hexafluoro isopropanol to produce different weight ratios of PLGA/SIS-blended nanofibrous membranes (NFM). Physicochemical characterization of the electrospun NFM was performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, water contact angle analysis, degradation test and tensile testing. The PLGA/SIS-blended NFM showed improved hydrophilicity and tensile strength. Better infiltration, attachment and proliferation of rat granulation fibroblasts of PLGA/SIS-blended NFMs compared to PLGA NFMs were identified by morphological differences determined by SEM and a water-soluble tetrazolium salt assay kit. Based on our results, the PLGA/SIS blended NFMs were found to be suitable for use as a potential material for wound dressing.     

The mechanical properties of polyurethane foam wound dressing hybridized with alginate hydrogel and jute fiber

The purpose of this study is to fabricate a smart wound dressing by hybridizing hydrophilic polyurethane foam (PUF) and alginate hydrogel. Hydrophilic PUF is used to maintain damaged tissue in a moist environment. Despite its many strong points as a wound dressing, hydrophilic PUF cannot be loaded with ingredients such as growth factors and cytokines that would enhance wound healing. Therefore, we introduce a pH-sensitive alginate hydrogel with the ability to selectively release drugs within the pH range of wounded skin. Due to the small pore size of PUF and the high viscosity of the alginate solution, the two are not easily penetrable. As such, a vacuum method is used to insert alginate hydrogel into the PUF. The optimum conditions for the vacuum method chosen are to be proposed. However, the mechanical strength of PUF decreased after containing alginate hydrogel. Therefore, Na-alginate powder for PUF, various types of crosslinking agents and jute fiber for alginate hydrogel were introduced to improve the mechanical properties of hydrogel/PUF hybrid wound dressing. Three different types of crosslinking agents are used for the gel formation. The most suitable crosslinking agent and its concentration for alginate hydrogel is also determined by the experiments. The experimental results are discussed with proper schemes and reasonable explanations.     

Process technology and properties evaluation of a chitosan-coated Tencel/cotton nonwoven fabric as a wound dressing

A double-layer nonwoven fabric containing Tencel, cotton, and chitosan was prepared by the immersion-precipitation phase-inversion method and evaluated as a wound covering. Macroporous structure of the chitosan membrane could control evaporative water loss, promote fluid drainage, and inhibit exogenous micro-organisms invasion due to inherent antimicrobial property of the chitosan. The chitosan membrane was hemostatic and could accelerate the healing of the wound. Histological examination showed that epithelialization rate was increased and the deposition of collagen in the dermis was well organized by covering the wound with the membrane. These results indicate that the chitosan-coated Tencel/cotton nonwoven fabric can be a potential material employed as a wound dressing.     

Development and characterization of bamboo gauze fabric coated with polymer and drug for wound healing

The bamboo yarn of Ne 40^s was used for the preparation of the Gauze fabric. The physical properties such as areal density and stiffness of fabrics were measured. The fabric was then scoured and bleached as per the standard procedure using distilled water. Chitosan-sodium alginate, Calcium-sodium alginate polymer and their mixture were coated separately on the gauze structure to improve the antibacterial and wound healing property of the bandage. Scanning electron microscope (SEM) analysis was carried out to observe the uniform distribution of polymers in the samples. The antibiotic drugs were selected based on the antibiotic sensitivity test. The drugs such as Tetracycline hydrochloride (250 mg), Chloramphenicol (250 mg) and Rifampicin (250 mg) were immobilized on the polymer coated fabrics to increase the rate of wound healing and antibacterial activity. The drug loaded samples were subjected to drug release study for about four days in a static condition. The results show that good amount of drug was released during all the four days. Further, the antibacterial activity of the drug loaded and polymer coated samples were evaluated against S. aureus and Proteus bacteria. The results show excellent antibacterial activity.     

In vivo evaluation of gelatin/hyaluronic acid nanofiber as Burn-wound healing and its comparison with ChitoHeal gel

The study aims at performing a comparative assessment of two types of burn wound treatment. The present study was designed to prepare crosslinked and blended two natural polymers nanofiber scaffolds using gelatin (GE) and hyaluronic acid (HA). The GE/HA composite nanofibrous membranes with varied GE/HA weight ratio have also been successfully fabricated by an electrospinning method. The average diameter of GE/HA fibers was in the range of 20 to 150 nm. In vivo efficacy was also investigated based on a deep second degree burns model for Wistar rats. At 14 days post-operation, the dermal defect basically recovered its normal condition. A percentage of wound closure of GE/HA composite nanofibrous membranes and ChitoHeal gel reached up to 81.9 % and 77.8 % respectively, compared with 65 % of the untreated control (p<0.05). Also, histological parameters were assessed on postoperative day 7 and 14. The results of in vivo experiments showed that more epidermis was formed in the gel and scaffold groups compared to the control group. The numbers of inflammatory cells in these two groups were also smaller as compared with the control group, which could well be the reason for the delayed healing in the control group.     

Collagen-Containing Fish Sidestream-Derived Protein Hydrolysates Support Skin Repair via Chemokine Induction

Restoring homeostasis following tissue damage requires a dynamic and tightly orchestrated sequence of molecular and cellular events that ensure repair and healing. It is well established that nutrition directly affects skin homeostasis, while malnutrition causes impaired tissue healing. In this study, we utilized fish sidestream-derived protein hydrolysates including fish collagen as dietary supplements, and investigated their effect on the skin repair process using a murine model of cutaneous wound healing. We explored potential differences in wound closure and histological morphology between diet groups, and analyzed the expression and production of factors that participate in different stages of the repair process. Dietary supplementation with fish sidestream-derived collagen alone (Collagen), or in combination with a protein hydrolysate derived from salmon heads (HSH), resulted in accelerated healing. Chemical analysis of the tested extracts revealed that Collagen had the highest protein content and that HSH contained the great amount of zinc, known to support immune responses. Indeed, tissues from mice fed with collagen-containing supplements exhibited an increase in the expression levels of chemokines, important for the recruitment of immune cells into the damaged wound region. Moreover, expression of a potent angiogenic factor, vascular endothelial growth factor-A (VEGF-A), was elevated followed by enhanced collagen deposition. Our findings suggest that a 5%-supplemented diet with marine collagen-enriched supplements promotes tissue repair in the model of cutaneous wound healing, proposing a novel health-promoting use of fish sidestreams.     

Enzyme-Digested Peptides Derived from Lates calcarifer Enhance Wound Healing after Surgical Incision in a Murine Model

Surgical wounds are common injuries of skin and tissues and usually become a clinical problem. Until now, various synthetic and natural peptides have been widely explored as potential drug candidates for wound healing. Inhibition of the TNF-α signaling pathway and promotion of angiogenesis are suggested to be involved in their effects. Angiogenesis at the wound site is one of the essential requisites for rapid healing. In the present study, a novel peptide extract derived from the natural source Lates calcarifer, commonly known as sea bass or barramundi, was evaluated for its wound healing property. The specific acidic and enzymatic approaches were employed for producing sea bass extract containing small size peptides (molecular weight ranging from 1 kD to 5 kD). The cytotoxicity of the extract was examined in HaCaT and NIH3T3. After this, the effects of enzyme digested peptide extracts of sea bass on wound healing in mice were investigated. The peptide extracts (660 and 1320 mg/kg/day) and control protein (1320 mg/kg/day) was orally given to the wounded mice, respectively, for 12 days. The surgical method was improved by implanting a silicone ring at the wound site. The ring avoided the contracting effect in murine wounds, making it more closely related to a clinical condition. The results showed promising improvement at the wound site in mice. Sea bass peptide extracts accelerated the wound healing process and enhanced the microvessel formation at the wound site. The remarkable effects of this novel sea bass peptide extract in healing traumatic injuries revealed a new option for developing wound management.     

Characterization of Isoforms of the Lectin Isolated from the Red Algae Bryothamnion seaforthii and Its Pro-Healing Effect

Lectins are a structurally heterogeneous group of proteins that have specific binding sites for carbohydrates and glycoconjugates. Because of their biotechnological potential, lectins are widely used in biomedical research. The present study aimed to evaluate the healing potential of the lectin isolated from the marine red alga Bryothamnion seaforthii (BSL). The lectin was purified using ion exchange chromatography with DEAE cellulose and characterized using tandem mass spectrometry. For healing tests, skin wounds were induced in the dorsal thoracic region of mice. These animals were randomly divided into three groups and subjected to topical treatment for 12 days with BSL, bovine serum albumin and 150 mM NaCl. To evaluate the potential of each treatment, the animals were anesthetized and sacrificed on days 2, 7 and 12, respectively. The parameters evaluated included the wound area, the proportion of wound closure and the histological diagnosis. The wound closure was more effective with BSL (Postoperative Day 7 and 12) than controls. The luminal epithelium was completely restructured; the presence of collagen in the dermis and the strongly active presence of young skin annexes demonstrate the potential of treatment with BSL compared with controls. Our findings suggest that BSL has pro-healing properties and can be a potential medical process in the treatment of acute wounds.