Silver Bandage Toxicity To Human Skin Cells And To Leg Ulcers
Vojtech Pavlik1, Kristina Nesporova, PhD1, Hana Vagnerova1, Natalie Cisarova1, Jaroslav Pejchal, PhD2, Barbora Safrankova, PhD1, Lubos Sobotka, PhD3.
1Contipro a.s., Dolni Dobrouc, Czech Republic, 2Department of Toxicology, University of Defence, Hradec Kralove, Czech Republic, 3Metabolic Disorder Clinic of University Hospital, Hradec Kralove, Czech Republic.
We investigated toxicity of bandages for wound healing with silver (three brands) or octenidine and hyaluronic acid (OCT-HA). The bandages were investigated in viability assays of keratinocytes and fibroblasts (NHEK, NHDF, respectively) and cell death flow-cytometry assay (all n=4). Ex vivo porcine skin was cultivated with the bandages on dermal side (n=4). Silver penetration was visualized with autometallography in porcine skin sections. γH2A.X was detected with immunofluorescence in the porcine skin and with WB in the skin homogenates. Gene expression was measured with qPCR (n=4). Patients (n=7) who gave a written consent were treated concomitantly on different parts of leg ulcers with silver bandage or OCT-HA. Biopsies were collected at the beginning, after 2 and 6 weeks and evaluated with histology - autometallography, trichrome stain and naphthol chloroacetate (granulocytes). Cell viability of both NHEK and NHDF treated with eluates from silver bandages was significantly decrased (p<0.05, t-test). NHDF died by necrosis after treatment with the eluates for 24 hours unlike the cells treated with OCT-HA eluate. Porcine skin incubated with silver bandages (27 or 51 hours) exhibited significantly higher DNA damage (elevated γH2A.X, p<0.05, t-test) and expression of stress genes HSPH1 and DNAJA1 (p<0.05, t-test). Silver penetrated deep into the ex vivo and in vivo tissues. Wounds treated with silver bandage had more granulocytes and inferior collagen maturation (both p<0.05) compared to OCT-HA after 2 weeks. High silver penetration, toxicity and no biodegradability impose unnecessary burden on the wounds. Therefore, use of silver bandages may slow down wound healing and one should consider safer alternatives.
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