Antibacterial photodynamic therapy with 808-nm laser and indocyanine green on abrasion wound models

Abstract

Infections with pathogens could cause serious health problems, such as septicemia and subsequent death. Some of these deaths are caused by nosocomial, chronic, or burn-related wound infections. Photodynamic therapy (PDT) can be useful for the treatment of these infections. Our aim was to investigate the antibacterial effect of indocyanine green (ICG) and 808-nm laser on a rat abrasion wound model infected with the multidrug resistant Staphylococcus aureus strain. Abrasion wounds were infected with a multidrug resistant clinical isolate of S. aureus. ICG concentrations of 500, 1000, and 2000 μg∕ml were applied with a 450 J∕cm2 energy dose. Temperature change was monitored by a thermocouple system. The remaining bacterial burden was determined by the serial dilution method after each application. Wounds were observed for 11 days posttreatment. The recovery process was assessed macroscopically. Tissue samples were also examined histologically by hematoxylin–eosin staining. Around a 90% reduction in bacterial burden was observed after applications. In positive control groups (ICG-only and laser-only groups), there was no significant reduction. The applied energy dose did not cause any thermal damage to the target tissue or host environment. Results showed that ICG together with a 808-nm laser might be a promising antibacterial method to eliminate infections in animals and accelerate the wound-healing process.

Antimicrobial photodynamic therapy in skin wound healing: A systematic review of animal studies

“…The animal species used in the 19 studies were mice (n = 16) and rats (n = 3) . Of the 16 mouse studies, nine used BALB/c mice, 4 utilised Swiss albino mice, two used C57BL/ksj db/db mice, and one used CD1 mice .…”

“…All wounds were generated on the dorsum of the animals. They were excisional wounds, burn wounds, and abrasion wounds . The wound sizes ranged from 6 mm in diameter to 1.5 × 1.5 cm 2 …”

“…To investigate the antimicrobial effect of PDT, the wounds in all studies were inoculated with one or two species of bacteria. The majority were P. aeruginosa and methicillin‐resistant S. aureus . Others were unresistant S. aureus strains, Escherichia coli , and Acinetobacter baumannii …”

“…It was used in two studies . Other used photosensitisers were 5‐phenyl‐10; 15, 20‐tris (N‐methyl‐4‐pyridyl) porphyrin chloride (PTMPP); sinoporphyrin sodium (also known as DVDMS); indocyanine green (ICG); pentalysine β‐carbonylphthalocyanine zinc (ZnPc‐[Lys] 5 ); zinc phthalocyanine tetrasulfonate (ZnPc‐S 4 ); poly‐L‐lysine conjugate of chlorine p6 (pl‐cp6), β‐lactamase‐activated EtNBS (LAEtNBS); RLP068/Cl, toluidine blue O (TBO); polyethylenimine‐chlorin(e6) (PEI‐ce6); and poly‐ l ‐lysine‐chlorin e6 (pL‐ce6) …”

“…In one study, burn wounds were simultaneously treated by both topical application and injection under the wound . The application route was not described in three studies . The incubation time ranged from 15 minutes to 90 minutes …”