Experimental Study on Blue Light Interaction with Human Keloid-Derived Fibroblasts

Abstract

Keloids are an exuberant response to wound healing, characterized by an exaggerated synthesis of collagen, probably due to the increase of fibroblasts activity and to the reduction of their apoptosis rate: currently no standard treatments or pharmacological therapies are able to prevent keloid recurrence. To reach this goal, in recent years some physical treatments have been proposed, and among them the PhotoBioModulation therapy (PBM). This work analyses the effects of a blue LED light irradiation (410–430 nm, 0.69 W/cm2 power density) on human fibroblasts, isolated from both keloids and perilesional tissues. Different light doses (3.43–6.87–13.7–20.6–30.9 and 41.2 J/cm2) were tested. Biochemical assays and specific staining were used to assess cell metabolism, proliferation and viability. Micro-Raman spectroscopy was used to explore direct effects of the blue LED light on the Cytochrome C (Cyt C) oxidase. We also investigated the effects of the irradiation on ionic membrane currents by patch-clamp recordings. Our results showed that the blue LED light can modulate cell metabolism and proliferation, with a dose-dependent behavior and that these effects persist at least till 48 h after treatment. Furthermore, we demonstrated that the highest fluence value can reduce cell viability 24 h after irradiation in keloid-derived fibroblasts, while the same effect is observed 48 h after treatment in perilesional fibroblasts. Electrophysiological recordings showed that the medium dose (20.6 J/cm2) of blue LED light induces an enhancement of voltage-dependent outward currents elicited by a depolarizing ramp protocol. Overall, these data demonstrate the potentials that PBM shows as an innovative and minimally-invasive approach in the management of hypertrophic scars and keloids, in association with current treatments.

Blue-LED-Light Photobiomodulation of Inflammatory Responses and New Tissue Formation in Mouse-Skin Wounds

“…These cells stimulated (i) an early inflammatory response; (ii) angiogenesis, thanks to the secretion of TNF-α [ 36 ]; and (iii) the response of fibroblasts that switched into myofibroblasts, which played a role in wound closure, evidenced by re-epithelialization and collagen deposition [ 36 , 37 , 38 , 39 , 40 , 41 ]. Therefore, together with our previous investigation [ 15 , 16 , 19 , 41 , 42 , 43 ], these results show that blue-LED-light irradiation induces a quicker healing process.…”

Ear keloids: An innovative 3‐steps combined treatment

“…According to the literature, the therapeutical effects of blue light has been reported but its mechanism is still partially unknown, it was observed that blue LED light may be used to modulate the metabolism and proliferation of human fibroblasts, and its effects on wound healing seemed to be particularly evident when studying fibroblast and keratinocyte co‐cultures 26–30 . Other authors considered that it is possible that blue light is absorbed by mitochondrial chromophores in the same way as red/infrared light, but also that can be several other distinct chromophores 31 …”

Photobiomodulation Therapy: A New Light in the Treatment of Systemic Sclerosis Skin Ulcers

“…Some authors have recently reported observations of an improved healing process when superficial wounds are treated with blue LED light with wavelengths in the range 410–430 nm, and a study in an animal model indicated that blue light led to a faster healing process in superficial lesions, with fibroblasts and myofibroblasts playing an important role [ 19 ]. After a critical literature review [ 22 ], further analyses of this group focused on the effects of blue light on fibroblasts and keratinocytes; it was observed that blue LED light may be used to modulate the metabolism and proliferation of human fibroblasts, and its effects on wound healing seemed to be particularly evident when studying fibroblast and keratinocyte co-cultures [ 20 , 21 ].…”