Early healing events in a porcine model of contaminated wounds: effects of nanocrystalline silver on matrix metalloproteinases, cell apoptosis, and healing

Abstract

A porcine model of wound healing was employed to examine the impact of nanocrystalline silver-coated dressings on specific wound healing events. Full-thickness wounds were created on the backs of pigs, contaminated with an experimental inoculum containing Pseudomonas aeruginosa, Fusobacterium sp., and coagulase-negative staphylococci, and covered with dressing products either containing silver or not. Nanocrystalline silver-coated dressings promoted rapid wound healing, particularly during the first several days post-injury. Healing was characterized by rapid development of well vascularized granulation tissue that supported tissue grafting 4 days post-injury, unlike control dressed wounds. The proteolytic environment of wounds treated with nanocrystalline silver was characterized by reduced levels of matrix metalloproteinases. Matrix metalloproteinases have been shown to be present in chronic ulcers at abnormally high levels, as compared with acute wounds, and may contribute to the nonhealing nature of these wounds. Cellular apoptosis occurred at a higher frequency in the nanocrystalline silver-treated wounds than in wounds dressed with other products. The results suggest that nanocrystalline silver may play a role in altering or compressing the inflammatory events in wounds and facilitating the early phases of wound healing. These benefits are associated with reduced local matrix metalloproteinase levels and enhanced cellular apoptosis.

Electrochemical and antimicrobial properties of diamondlike carbon-metal composite films

“…Silver may also possess anti-inflammatory properties; for example, studies have shown increased neutrophil apoptosis, reduced matrix metalloproteinase activity, reduced tumor necrosis factor-alpha levels, and more rapid healing in wounds dressed with silver [15][16][17][18][19]. Silver must be in a soluble, uncharged (Ag 0 ) or metallic (Ag +1 ) form to provide these biological effects [7].…”

Electrospinning of Gelatin Functionalized with Silver Na-noparticles for Nanofiber Fabrication

“…Bacterial colonization and subsequent infection can interfere with the wound healing process by producing various substances (e.g., toxins, proteases and proinflammatory molecules) which may cause an excessive and prolonged inflammatory response of the host tissues [16][17][18][19].…”

“…Idealantimicrobial dressings should have a number of key attributes, including provision of a moist environment to enhance healing [20], and broad-spectrum antimicrobial activity, including activity against antibioticresistant bacteria [e.g., methicillin-resistant Staphylococcus aureus (MRSA)] [16][17][18][19]. A recent resurgence of the use of silver-based dressings has been ascribed to their broadspectrum antibacterial activity, as well as to a less possibility for inducing bacterial resistance than antibiotics [17,18].…”

A Comparative Study of the Burn Wound Healing Properties of Saline-Soaked Dressing and Silver Sulfadiazine in Rats

“…Silver-based technologies added benefits by down-regulating tissue inhibitors of metalloproteinase to levels that facilitate wound healing [10].the results of several studies suggest that nanocrystalline silver specifically may play a role in altering or compressing the inflammatory events in wounds and facilitating the early phases of wound healing. These benefits are associated with reduced local matrix metalloproteinase levels and enhanced cellular apoptosis [12,13]. 3-Zinc metabolism was up regulated, implying increases epithelialization [14,15].…”