Continuous electrical current and zinc sulphate administered by transdermal iontophoresis improves skin healing in diabetic rats induced by alloxan: morphological and ultrastructural analysis

Investigation of the antimicrobial effect of anodic iontophoresis on Gram-positive and Gram-negative bacteria for skin infections treatment

Iontophoresis, a non-invasive application of a constant low-intensity electric current, is a promising strategy to accelerate wound healing. Although its mechanisms are not yet fully elucidated, part of its action seems related to inhibiting bacteria growth. This work aimed to investigate the antimicrobial effect of iontophoresis using Staphylococcus epidermidis and Escherichia coli strains, Gram-positive and Gram-negative bacteria, respectively. Anodic iontophoresis was applied to each bacterial suspension using Ag/AgCl electrodes, and bacteria viability was evaluated after 24 h incubation by counting colony-forming units. A Quality-by-Design approach was performed to assess the influence of the iontophoresis' intensity and application time on bacterial viability. Cell morphology was evaluated by scanning electron microscopy. Iontophoresis showed antimicrobial effects on the Gram-positive bacteria only at 5 mA and 60 min application. However, a linear relationship was observed between intensity and application time for the Gram-negative one, causing drastic morphological changes and up to 98 % death. The cell wall of Gram-negative bacteria seems more susceptible to disorganization triggered by iontophoresis-induced ion transport than Gram-positive ones. Therefore, anodic iontophoresis can be a powerful ally in controlling Gram-negative bacteria proliferation in wounds.

Efficacy of Biophysical Energies on Healing of Diabetic Skin Wounds in Cell Studies and Animal Experimental Models: A Systematic Review

We have systematically assessed published cell studies and animal experimental reports on the efficacy of selected biophysical energies (BPEs) in the treatment of diabetic foot ulcers. These BPEs include electrical stimulation (ES), pulsed electromagnetic field (PEMF), extracorporeal shockwave (ECSW), photo energies and ultrasound (US). Databases searched included CINAHL, MEDLINE and PubMed from 1966 to 2018. Studies reviewed include animal and cell studies on treatment with BPEs compared with sham, control or other BPEs. Information regarding the objective measures of tissue healing and data was extracted. Eighty-two studies were eventually selected for the critical appraisal: five on PEMF, four each on ES and ECSW, sixty-six for photo energies, and three about US. Based on the percentage of original wound size affected by the BPEs, both PEMF and low-level laser therapy (LLL) demonstrated a significant clinical benefit compared to the control or sham treatment, whereas the effect of US did not reveal a significance. Our results indicate potential benefits of selected BPEs in diabetic wound management. However, due to the heterogeneity of the current clinical trials, comprehensive studies using well-designed trials are warranted to confirm the results.

Chitosan Membrane Modified With a New Zinc(II)-Vanillin Complex Improves Skin Wound Healing in Diabetic Rats

The treatment of chronic wounds is considered a public health problem. When the condition affects at-risk groups such as those with diabetics, it becomes a great clinical challenge. In this work, we evaluated the healing effects of a new zinc complex, [Zn(phen)(van)2], identified as ZPV, which was synthesized, characterized and associated with chitosan (CS) membranes and tested on cutaneous wounds of diabetic rats. Chitosan membranes were modified by Schiff base reaction with the complex under two experimental conditions (14 and 21 days), resulting in membranes with concentrations of complex equal to 0.736 μmol cm-2 (CS-ZPV1) and 1.22 μmol cm-2 (CS-ZPV2). Release assays in aqueous medium indicated that the membranes release the complex gradually when exposed to an aqueous medium. Diabetes was inducted in Wistar rats using 40 mg/kg (i.v.) streptozotocin. On the 7th day after diabetic induction, a circular excision on the skin (1.0 cm) was performed with a punch. The lesions were treated with the pure chitosan membrane and the membrane associated with the zinc-vanillin complex in two different doses. Skin samples were subjected to macroscopic and histopathological analyses, cytokine (TNF-α, IL-1β, and IL-10) quantification and reverse transcriptase polymerase chain reaction (TGF-β and VEGF) assays. The analyses showed a decrease in wound size, reepithelialization, angiogenic stimulus, collagen deposition, and reduced levels of TNF-α and IL-1β as well as increased IL-10 and gene expression of TGF-β and VEGF. The evaluated parameters suggest that CS-ZPV in the two concentrations tested may be effective in the treatment of chronic wounds.

Smart Bandages: The Future of Wound Care

Chronic non-healing wounds are major healthcare challenges that affect a noticeable number of people; they exert a severe financial burden and are the leading cause of limb amputation. Although chronic wounds are locked in a persisting inflamed state, they are dynamic and proper therapy requires identifying abnormalities, administering proper drugs and growth factors, and modulating the conditions of the environment. In this review article, we discuss technologies that have been developed to actively monitor the wound environment. We also highlight drug delivery tools that have been integrated with bandages to facilitate precise temporal and spatial control over drug release and review automated or semi-automated systems that can respond to the wound environment.

Repeated Whole-Body Exposure to Low-Dose Radiation Combined With Topical Application of Basic Fibroblast Growth Factor and Zinc Accelerates Wound Healing in Diabetic Rats

We reported the acceleration of skin wound healing in diabetic rats by repeated exposure to low-dose radiation (LDR). Here, we explored whether the wound healing could be further improved when LDR was combined with a topical application of basic fibroblast growth factor (bFGF) or zinc. Wounds were established on the backs of type 1 diabetic rats induced by a single injection of streptozotocin. Rats were treated daily with normal saline (Diabetes), LDR, bFGF, zinc, or combined 3 treatments for 5 consecutive days with a 2-day break between each consecutive 5-day treatment. Changes in wound size, histopathology, and microvessel density were assessed on days 5, 10, and 15, respectively, once treatment is started. All treatment regimens significantly accelerated skin wound healing, tissue remodeling, and new vessel formation compared to diabetes group. However, the combined LDR plus bFGF and zinc provided a better beneficial effect on wound healing than either one of these treatments alone. Further, we found that the effects of LDR and bFGF were similar, whereas zinc alone induced a weaker response. Our results suggest that whole-body LDR plus the topical application of bFGF and zinc can further accelerate wound healing in diabetic rats.