Diabetic Wound Model Research Articles

Complement Activation and STAT4 Expression Are Associated with Early Inflammation in Diabetic Wounds.

Diabetic non-healing wounds are a major clinical problem. The mechanisms leading to poor wound healing in diabetes are multifactorial but unresolved inflammation may be a major contributing factor. The complement system (CS) is the most potent inflammatory cascade in humans and contributes to poor wound healing in animal models. Signal transducer and activator of transcription 4 (STAT4) is a transcription factor expressed in immune and adipose cells and contributes to upregulation of some inflammatory chemokines and cytokines. Persistent CS and STAT4 expression in diabetic wounds may thus contribute to chronic inflammation and delayed healing. The purpose of this study was to characterize CS and STAT4 in early diabetic wounds using db/db mice as a diabetic skin wound model. The CS was found to be activated early in the diabetic wounds as demonstrated by increased anaphylatoxin C5a in wound fluid and C3-fragment deposition by immunostaining. These changes were associated with a 76% increase in nucleated cells in the wounds of db/db mice vs. controls. The novel classical CS inhibitor, Peptide Inhibitor of Complement C1 (PIC1) reduced inflammation when added directly or saturated in an acellular skin scaffold, as reflected by reduced CS components and leukocyte infiltration. A significant increase in expression of STAT4 and the downstream macrophage chemokine CCL2 and its receptor CCR2 were also found in the early wounds of db/db mice compared to non-diabetic controls. These studies provide evidence for two new promising targets to reduce unresolved inflammation and to improve healing of diabetic skin wounds.

Stromal Cell-Derived Growth Factor-1 Alpha-Elastin Like Peptide Fusion Protein Promotes Cell Migration and Revascularization of Experimental Wounds in Diabetic Mice.

Objective: In previous work, we demonstrated the development of a novel fusion protein containing stromal cell-derived growth factor-1 alpha juxtaposed to an elastin-like peptide (SDF1-ELP), which has similar bioactivity, but is more stable in elastase than SDF1. Herein, we compare the ability of a single topical application of SDF1-ELP to that of SDF1 in healing 1 × 1 cm excisional wounds in diabetic mice. Approach: Human Leukemia-60 cells were used to demonstrate the chemotactic potential of SDF1-ELP versus SDF1 in vitro. Human umbilical vascular endothelial cells were used to demonstrate the angiogenic potential of SDF1-ELP versus SDF1 in vitro. The bioactivity of SDF1-ELP versus SDF1 after incubation in ex-vivo diabetic wound fluid was compared. The in-vivo effectiveness of SDF1-ELP versus SDF1 was compared in diabetic mice wound model by monitoring for the number of CD31+ cells in harvested wound tissues. Results: SDF1-ELP promotes the migration of cells and induces vascularization similar to SDF1 in vitro. SDF1-ELP is more stable in wound fluids compared to SDF1. In vivo, SDF1-ELP induced a higher number of vascular endothelial cells (CD31+ cells) compared to SDF1 and other controls, suggesting increased vascularization. Innovation: While growth factors have been shown to improve wound healing, this strategy is largely ineffective in chronic wounds. In this work, we show that SDF1-ELP is a promising agent for the treatment of chronic skin wounds. Conclusion: The superior in vivo performance and stability of SDF1-ELP makes it a promising agent for the treatment of chronic skin wounds.

Accelerated wound healing in a diabetic rat model using decellularized dermal matrix and human umbilical cord perivascular cells.

The aim of the present study was to design a novel tissue-engineered system to promote angiogenesis, re-epithelization and granulation of skin tissue using human umbilical cord perivascular stem cells and decellularized dermal matrix natural scaffolds in rat diabetic wound models. The authors of this research article have been working on stem cells and tissue engineering scaffolds for years. According to our knowledge, there is a lack of an efficient system for the treatment of skin defects using tissue engineering strategy. Since the rates of angiogenesis, re-epithelization and granulation tissue are directly correlated with full thickness wound healing, the proposed HUCPVCs-loaded DDM scaffolds perfectly fills the niche neglected by current treatment strategies. This pre-clinical study demonstrates the proof-of-concept that necessitates clinical evaluations.

Human endothelial progenitor cells-derived exosomes accelerate cutaneous wound healing in diabetic rats by promoting endothelial function

AimsWound healing is deeply dependent on neovascularization to restore blood flow. The neovascularization of endothelial progenitor cells (EPCs) through paracrine secretion has been reported in various tissue repair models. Exosomes, key components of cell paracrine mechanism, have been rarely reported in wound healing. MethodsExosomes were isolated from the media of EPCs obtained from human umbilical cord blood. Diabetic rats wound model was established and treated with exosomes. The in vitro effects of exosomes on the proliferation, migration and angiogenic tubule formation of endothelial cells were investigated. ResultsWe revealed that human umbilical cord blood EPCs derived exosomes transplantation could accelerate cutaneous wound healing in diabetic rats. We also showed that exosomes enhanced the proliferation, migration and tube formation of vascular endothelial cells in vitro. Furthermore, we found that endothelial cells stimulated with these exosomes would increase expression of angiogenesis-related molecules, including FGF-1, VEGFA, VEGFR-2, ANG-1, E-selectin, CXCL-16, eNOS and IL-8. ConclusionTaken together, our findings indicated that EPCs-derived exosomes facilitate wound healing by positively modulating vascular endothelial cells function.

Comparative efficacy of two polyherbal creams with framycetin sulfate on diabetic wound model in rats

BackgroundDiabetes mellitus is one of the metabolic disorders that impede normal steps of wound healing process. Worldwide, 15% of the 200 million diabetics suffer from diabetic wounds. Diabetic complications, such as foot ulcer, impose major public health burdens worldwide. ObjectiveThe present study was carried out to evaluate comparative efficacy of polyherbal creams with framycetin sulfate cream on diabetic rats using incision and excision wound models. Materials and methodsAlloxan (120 mg/kg, intraperitoneal) induced diabetic rat models (incision and excision models) were used to evaluate wound healing effect of cream A, B, and framycetin sulfate. Cream A and B were applied for a period of 10 and 20 days for incision and excision wound models, respectively. Incision wound model was used to assess the effect on breaking strength. Wound contraction and epithelialization period were measured using excision wound model. The data were analyzed by one-way ANOVA followed by Bonferroni post-test. ResultsTensile strength of the animals treated with cream B (941.66 ± 15.36) was found to be significantly greater (P < 0.001) as compared to tensile strength of the animals treated with cream A (825 ± 22.36). Wound treated with cream B was found to heal significantly (P < 0.001) faster (day 17) as compared to wounds treated with framycetin sulfate (day 21). ConclusionsCream B was found to be more effective wound healing agent than cream A and framycetin sulfate cream in treating diabetic wounds.

Compromised Wound Healing in Ischemic Type 2 Diabetic Rats.

Ischemia is one of the main epidemic factors and characteristics of diabetic chronic wounds, and exerts a profound effect on wound healing. To explore the mechanism of and the cure for diabetic impaired wound healing, we established a type 2 diabetic rat model. We used an 8weeks high fat diet (HFD) feeding regimen followed by multiple injections of streptozotocin (STZ) at a dose of 10mg/kg to induce Wister rat to develop type 2 diabetes. Metabolic characteristics were assessed at the 5th week after the STZ injections to confirm the establishment of diabetes mellitus on the rodent model. A bipedicle flap, with length to width ratio 1.5, was performed on the back of the rat to make the flap area ischemic. Closure of excisional wounds on this bipedicle flap and related physiological and pathological changes were studied using histological, immunohistochemical, real time PCR and protein immunoblot approaches. Our results demonstrated that a combination of HFD feeding and a low dose of STZ is capable of inducing the rats to develop type 2 diabetes with noticeable insulin resistance, persistent hyperglycemia, moderate degree of insulinemia, as well as high serum cholesterol and high triglyceride levels. The excision wounds on the ischemic double pedicle flap showed deteriorative healing features comparing with non-ischemic diabetic wounds, including: delayed healing, exorbitant wound inflammatory response, excessive and prolonged ROS production and excessive production of MMPs. Our study suggested that HFD feeding combined with STZ injection could induce type 2 diabetes in rat. Our ischemic diabetic wound model is suitable for the investigation of human diabetic related wound repair; especically for diabetic chronic wounds.

Microsensor and transcriptomic signatures of oxygen depletion in biofilms associated with chronic wounds.

Biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms and by the responding leukocytes, may impede wound healing by depleting the oxygen that is required for healing. In this study, oxygen microsensors to measure oxygen transects through in vitro cultured biofilms, biofilms formed in vivo within scabs from a diabetic (db/db) mouse wound model, and ex vivo human chronic wound specimens was used. The results showed that oxygen levels within mouse scabs had steep gradients that reached minima ranging from 17 to 72 mmHg on live mice and from 6.4 to 1.1 mmHg on euthanized mice. The oxygen gradients in the mouse scabs were similar to those observed for clinical isolates cultured in vitro and for human ex vivo specimens. To characterize the metabolic activities of the bacteria in the mouse scabs, transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds was performed. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results also indicated that the bacteria within the wounds experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results supported the hypothesis that bacterial biofilms in chronic wounds promote chronicity by contributing to the maintenance of localized low oxygen tensions, through their metabolic activities and through their recruitment of cells that consume oxygen for host defensive processes.

Protease-sensitive atelocollagen hydrogels promote healing in a diabetic wound model.

The design of exudate-managing wound dressings is an established route to accelerated healing, although such design remains a challenge from material and manufacturing standpoints. Aiming towards the clinical translation of knowledge gained in vitro with highly-swollen rat tail collagen hydrogels, this study investigated the healing capability in a diabetic mouse wound model of telopeptide-free, protease-inhibiting collagen networks. 4-Vinylbenzylation and UV irradiation of type I atelocollagen (AC) led to hydrogel networks with chemical and macroscopic properties comparable to previous collagen analogues, attributable to similar lysine content and dichroic properties. After 4 days in vitro, hydrogels induced nearly 50 RFU% reduction in matrix metalloproteinase (MMP)-9 activity, whilst showing less than 20 wt% mass loss. After 20 days in vivo, dry networks promoted 99% closure of 10 × 10 mm full thickness wounds and accelerated neo-dermal tissue formation compared to Mepilex®. This collagen system can be equipped with multiple, customisable properties and functions key to personalised chronic wound care.

Heme Oxygenase-1 Promotes Delayed Wound Healing in Diabetic Rats.

Diabetic ulcers are one of the most serious and costly chronic complications for diabetic patients. Hyperglycemia-induced oxidative stress may play an important role in diabetes and its complications. The aim of the study was to explore the effect of heme oxygenase-1 on wound closure in diabetic rats. Diabetic wound model was prepared by making an incision with full thickness in STZ-induced diabetic rats. Wounds from diabetic rats were treated with 10% hemin ointment for 21 days. Increase of HO-1 protein expression enhanced anti-inflammation and antioxidant in diabetic rats. Furthermore, HO-1 increased the levels of VEGF and ICAM-1 and expressions of CBS and CSE protein. In summary, HO-1 promoted the wound closure by augmenting anti-inflammation, antioxidant, and angiogenesis in diabetic rats.

In vitro characterization of human hair follicle dermal sheath mesenchymal stromal cells and their potential in enhancing diabetic wound healing

Background aimsLittle is published on the characterization and therapeutic potential of human mesenchymal cells derived from hair follicle (HF) dermal sheath (DS). In this study, we isolated and characterized HF DS-mesenchymal stromal cells (DS-MSCs) with respect to the bone marrow mesenchymal stromal cells (BM-MSCs). We further tested if DS-MSC–conditioned medium (CM), like what was previously reported for BM-MSC CM, has superior wound-healing properties, in both in vitro and in vivo wound models compared with skin fibroblast CM. MethodsDS-MSCs were isolated from HF and cultured in vitro to assess long-term growth potential, colony-forming efficiency (CFE), expression of CD surface markers and differentiation potential. The cytokine expression of DS-MSC CM was determined through an antibody-based protein array analysis. The wound-healing effects of the CM were tested in vitro with the use of human cell cultures and in vivo with the use of a diabetic mouse wound model. ResultsIn vitro results revealed that DS-MSCs have high growth capacity and CFE while displaying some phenotypes similar to BM-MSCs. DS-MSCs strongly expressed many surface markers expressed in BM-MSCs and could also differentiate into osteoblasts, chondrocytes and adipocytes. DS-MSCs secreted significantly higher proportions of paracrine factors such as interleukin-6 (IL-6), IL-8 and growth-related oncogene. DS-MSC-CM demonstrated enhanced wound-healing effects on human skin keratinocytes, fibroblasts and endothelial cells in vitro, and the wound-healing time in diabetic mice was found to be shorter, compared with vehicle controls. ConclusionsHuman HF DS stromal cells demonstrated MSC-like properties and might be an alternative source for therapeutic use in wound healing.

Dysregulation of collagen production in diabetes following recurrent skin injury: contribution to the development of a chronic wound.

Recurrent injury has been implicated in the development of chronic diabetic wounds. We have developed a chronic diabetic wound model based upon recurrent injury in diabetic mice. We hypothesized that dysregulation of collagen production at both the mRNA and microRNA levels contributes to the development of chronic diabetic wounds. To test this, both diabetic and nondiabetic mice were made to undergo recurrent injury. Real-time PCR for TGF-β1, SMAD-3, Col1α1, Col3α1, microRNA-25, and microRNA-29a and Western blot for collagen I and III were performed 7 days following each injury. Diabetic wounds displayed decreased collagen at all time points. This was associated with dysregulated collagen production at both the gene and microRNA levels at all time points. Following the final injury, however, diabetic collagen production significantly improved. This appeared to be due to a substantial decrease in both microRNAs as well as an increase in the expression of collagen pathway genes. That dysregulated collagen production progressed throughout the course of wounding suggests that this is one factor contributing to the development of chronic diabetic wounds. Future studies using this model will allow for the determination of other factors that may also contribute to the development and/or persistence of chronic diabetic wounds.

Allogenous skin fibroblast transplantation enhances excisional wound healing following alloxan diabetes in sheep, a randomized controlled trial

BackgroundHealing of skin wound is a multi-factorial and complex process. Treatment of diabetic wounds is still a major clinical challenge. Recently, stem cell transplantation to chronic wounds is favored. The objective of this study was to evaluate effects of pre-labeled allogenous skin fibroblasts on healing of ovine diabetic wound model. MethodsEight 4-month-old Iranian Makoui wethers were used in this study. Alloxan monohydrate was used for induction of diabetes. In each wether two excisional wound were created on dorsum of the animal. Wounds of one side were randomly chosen as treatment group (n = 8), and wounds of the other side were considered as control group (n = 8). Pre-labeled skin fibroblasts with bromodeoxyuridine were used in wounds of one side as treatment. Photographs were taken in distinct times for planimetric evaluation. Wound samples were taken for BrdU detection and histopathologic evaluations on day 21 post-wounding. ResultsThe planimetric study showed closure of fibroblast treated wounds is significantly faster than control group (P < 0.05). Immunohistochemical staining with anti-bromodeoxyuridine antibody indicated presence of transplanted cells in the wounds. Histopathologic evaluations of H&E stained sections disclosed significantly increasing of re-epithelialization, number of fibroblasts, and number of blood vessels in treatment group in comparison to control group (P < 0.05). ConclutionThe results of this study indicated that allogenous skin fibroblast transplantation can positively affect wound healing in diabetic sheep.

Priming with proangiogenic growth factors and endothelial progenitor cells improves revascularization in linear diabetic wounds

In the present study, we investigated whether proangiogenic growth factors and endothelial progenitor cells (EPCs) induce favourable effects on cutaneous incisional wound healing in diabetic mice. The proangiogenic effects of human EPCs were initially analyzed using a HUVEC in vitro angiogenesis assay and an in vivo Matrigel assay in nude mice (n=12). For the diabetic wound model, 48 Balb/c mice with streptozotocin (STZ)-induced diabetes were divided randomly into 4 groups (12 mice in each group). Subsequently, 3, 5 and 7 days before a 15-mm full-thickness incisional skin wound was set, group 1 was pre-treated subcutaneously with a mixture of vascular endothelial growth factor (VEGF)/basic fibroblast growth factor (bFGF)/platelet-derived growth factor (PDGF) (3.5 μg of each), group 2 with 3.5 μg PDGF and group 3 with an aliquot of two million EPCs, whereas the control animals (group 4) were pre-treated with 0.2 ml saline solution. The wounds were assessed daily and the repaired tissues were harvested 7 days after complete wound closure. The angiogenesis assay demonstrated significantly increased sprout densities, areas and lengths in the EPC-treated group (all p<0.01). In the Matrigel assay, significantly increased microvessel densities, areas and sizes (all p<0.001) were also detected in the EPC-treated group. In the STZ-induced model of diabetes, the animals pre-treated with a combination of proangiogenic factors and EPCs showed in general, a more rapid wound closure. Vessel densities were >2-fold higher in the mice treated with a combination of proangiogenic factors and EPCs (p<0.05) and tensile strengths were higher in the groups treated with proangiogenic growth factors compared to the controls (p<0.05). These results suggest a beneficial effect of pre-treatment with proangiogenic growth factors and EPCs in incisional wound healing.

Preliminary investigation of topical nitroglycerin formulations containing natural wound healing agent in diabetes‐induced foot ulcer

Nitroglycerin (NTG) is an organic nitrate rapidly denitrated by enzymes to release free radical nitric oxide and shows improved wound healing and tissue protection from oxidative damage. The purpose of this study was to evaluate whether topical application of NTG in the form of gel/ointment along with a natural wound healing agent, aloe vera, would bring about wound healing by using diabetes-induced foot ulcer model and rat excision wound model. All these formulations were evaluated for pH, viscosity, drug content and ex vivo diffusion studies using rat skin. Based on ex vivo permeation studies, the formulation consisting of carbopol 974p as a gelling agent and aloe vera was found to be suitable. The in vivo study used streptozotocin-induced diabetic foot ulcer and rat excision wound models to analyse wound healing activity. The wound size in animals of all treated groups was significantly reduced compared with that of the diabetic control and marketed treated animals. This study showed that the gel formed with carbopol 974p (1%) and aloe vera promotes significant wound healing and closure in diabetic rats compared with the commercial product and provides a promising product to be used in diabetes-induced foot ulcer.

Deferoxamine enhances neovascularization and accelerates wound healing in diabetic rats via the accumulation of hypoxia-inducible factor-1α

AimsHypoxia-inducible factor (HIF)-1α plays a pivotal role during the process of wound healing. Previous studies reported that deferoxamine (DFO) could increase HIF-1α stability. This study aimed to investigate the effects of DFO on wound healing in diabetic rats and explore the underlying mechanism both in vivo and in vitro. MethodsAn excisional diabetic wound model was established and the wound healing among vehicle control, DFO and vascular endothelial growth factor (VEGF) treatment groups was evaluated by macroscopy, histology and Western blot analysis. Human umbilical vein endothelial cells (HUVECs) were treated with DFO or HIF-1α siRNA, and then endothelial tube formation, cell proliferation and migration were examined. ResultsDFO-treated wounds exhibited accelerated wound healing with enhanced granulation formation and increased re-epithelialization. Compared to the vehicle or VEGF treatment, DFO significantly increased neovascularization through up-regulation of HIF-1α and target genes including VEGF and stromal cell-derived factor-1α (SDF-1α). DFO failed to stimulate the expression of VEGF and SDF-1α in HUVECs depleted of HIF-1α. In addition, DFO promoted the angiogenic-associated processes of endothelial tube formation, cell proliferation and migration in HIF-1α dependent manner. ConclusionsDFO enhances neovascularization and accelerates diabetic wound healing through the accumulation of HIF-1α and the regulation of endothelial cell function.

Impact of low-energy extracorporeal shock wave on collagen deposition and transforming growth factor-β1 expression in excisional wound of diabetic rats

Objective To investigate the effect of low-energy extracorporeal shock wave (ESW)treatment on collagen deposition and transforming growth factor-β1 (TGF-β1) expression in excisional wound of diabetic rats,and the possible mechanism of ESW promoting wound healing.Methods Chronic diabetic wound models were made in 64 6-8-week-old male SD rats weighing (220 ±20) g,and randomly divided into the ESW treatment group and the diabetic control group.Normal wound models were made in 32 SD rats and were used as the normal control group.In ESW treatment group,wound was treated by ESW with 0.11 mJ/mm2,1.5 Hz and 500 pulses one day post-wounding.In diabetic control group and normal control group,wound was only given coupling fluid and received no ESW treatment.Wound closing rate was calculated at 3rd,7th,14th and 21st day after treatment.Wound specimens were harvested to observe histological changes,hydroxyproline contents,density of collagen fibers and TGF-β1 expression.Resuits At different time points after treatment,collagen deposition,the relative density of collagen and hydroxyproline content were decreased in the diabetic control group as compared with those in the normal control group (P ＜ 0.05).At the same time,TGF-β1 expression was significantly decreased in the diabetic control group (P ＜ 0.05).After ESW treatment,fibroblasts and granulation tissue formation were increased,and collagen fibers density and hydroxyproline content in the wound were also increased simultaneously (P ＜ 0.05),and there was no significant difference in collagen fibers density and hydroxyproline content between the ESW group and normal control group (P ＞0.05).In addition,TGF-β1 expression at different time points was increased (P ＜ 0.05) and began to decline at 14th day in the ESW treatment group as compared with that in the diabetic control group.Conclusion The reduced collagen deposition is a major contributor of impaired diabetic wound healing and ESW treatment may increase the expression of TGF-β1,fibroblast migration or proliferation,collagen formation and hydroxyproline content within the wound tissue,and thus accelerate granulation tissue formation and wound healing process. Key words: Diabetes ; Wound; Collagen ; Transforming growth factor-β1

The effect of epidermal growth factor (EGF) conjugated with low-molecular-weight protamine (LMWP) on wound healing of the skin

This study was designed to develop a skin permeable recombinant low-molecular-weight protamine (LMWP) conjugated epidermal growth factor (EGF) (rLMWP-EGF) by linking a highly positive charged LMWP to the N-terminal of EGF through genetic recombination. We evaluated its biological activity, skin permeability, and wound healing efficacy in vivo. The cDNA for rLMWP-EGF was prepared by serial polymerase chain reaction for encoding amino acids of LMWP to the vector for EGF. After expression and purification, recombinant EGF site-specifically conjugated with LMWP was obtained. The in vitro cell proliferation activity was well preserved after LMWP conjugation and was comparable to that of rEGF. rLMWP-EGF showed markedly improved permeability through the three-dimensional artificial human skin constructs, and the cumulative permeation of rLMWP-EGF across the excised mouse skin was about 11 times higher than that of rEGF. Topically applied rLMWP-EGF significantly accelerated the wound closure rate in full thickness as well as a diabetic wound model most probably due to its enhanced skin permeation. These findings demonstrate the therapeutic potential of rLMWP-EGF as a new topical wound healing drug and the site-specific conjugation of LMWP to peptides or proteins by genetic recombination as a useful method for preparing highly effective biomedicines.

Amniotic Mesenchymal Stem Cells Enhance Wound Healing in Diabetic NOD/SCID Mice through High Angiogenic and Engraftment Capabilities

Although human amniotic mesenchymal stem cells (AMMs) have been recognised as a promising stem cell resource, their therapeutic potential for wound healing has not been widely investigated. In this study, we evaluated the therapeutic potential of AMMs using a diabetic mouse wound model. Quantitative real-time PCR and ELISA results revealed that the angiogenic factors, IGF-1, EGF and IL-8 were markedly upregulated in AMMs when compared with adipose-derived mesenchymal stem cells (ADMs) and dermal fibroblasts. In vitro scratch wound assays also showed that AMM-derived conditioned media (CM) significantly accelerated wound closure. Diabetic mice were generated using streptozotocin and wounds were created by skin excision, followed by AMM transplantation. AMM transplantation significantly promoted wound healing and increased re-epithelialization and cellularity. Notably, transplanted AMMs exhibited high engraftment rates and expressed keratinocyte-specific proteins and cytokeratin in the wound area, indicating a direct contribution to cutaneous closure. Taken together, these data suggest that AMMs possess considerable therapeutic potential for chronic wounds through the secretion of angiogenic factors and enhanced engraftment/differentiation capabilities.

Topical prolyl hydroxylase domain-2 silencing improves diabetic murine wound closure.

Prolyl hydroxylase domain 2 (PHD2) has been implicated in several pathways of cell signaling, most notably in its regulation of hypoxia-inducible factor (HIF)-1α stability. In normoxia, PHD2 hydroxylates proline residues on HIF-1α, rendering it inactive. However, in hypoxia, PHD2 is inactive, HIF-1α is stabilized and downstream effectors such as vascular endothelial growth factor and fibroblast growth factor-2 are produced to promote angiogenesis. In the present study we utilize RNA interference to PHD2 to promote therapeutic angiogenesis in a diabetic wound model, presumably by the stabilization of HIF-1α. Stented wounds were created on the dorsum of diabetic Lepr db/db mice. Mice were treated with PHD2 small interfering RNA (siRNA) or nonsense siRNA. Wounds were measured photometrically on days 0-28. Wounds were harvested for histology, protein, and RNA analysis. Diabetic wounds treated with siRNA closed within 21±1.2 days; sham-treated closed in 28±1.5 days. By day 7, Western blot revealed near complete suppression of PHD protein and corresponding increased HIF-1α. Angiogenic mediators vascular endothelial growth factor and fibroblast growth factor-2 were elevated, corresponding to increased CD31 staining in the treated groups. siRNA-mediated silencing of PHD2 increases HIF-1α and several mediators of angiogenesis. This corresponded to improved time to closure in diabetic wounds compared with sham-treated wounds. These findings suggest that impaired wound healing in diabetes can be ameliorated with therapeutic angiogenesis.

Impact of Achyranthes aspera L. on Protein Profile in Impaired Wound Models

In the present study, comparative protein profile of granulation tissues of burn, diabetic and immunocompromised wounds treated with 5.0% (w/w) ointment of methanol extract of Achyranthes aspera was undertaken. Granulation tissue of A. aspera treated group showed expression of a protein with molecular weight 69.4 kD in burn wound and proteins ranging from high, medium and low molecular weight (61.0, 55.0 and 31.5kD) in diabetic and immunocompromised wounds. A. aspera treatment induced expression of a particular protein of molecular weight 31.5 kD in both diabetic and immunocompromised wound models, signifying that this particular protein might play a key role in A. aspera mediated wound healing in these two models. © 2011 IGJPS. All rights reserved