Photoactivated rose bengal mitigates a fibrotic phenotype and improves cutaneous wound healing in full-thickness injuries.

Healing of deep cutaneous wounds often results in detrimental sequelae, including painful and debilitating scars. Current therapies for full-thickness injuries that target specific phases of wound healing have moderate success; however, full resolution remains incomplete and negative consequences persist if skin homeostasis is not achieved. Photoactivated molecules can modulate cellular responses by generating reactive oxygen species and may provide a novel therapeutic option to improve wound healing. In the current study, we investigated the effects of Rose bengal (RB) dye in a preclinical model of full-thickness cutaneous injury. Monochromatic green light activates RB to generate ROS in the presence of oxygen, subsequently crosslinking collagen fibrils. In in vitro studies, we show that photoactivated RB is well tolerated by epidermal keratinocytes and dermal fibroblasts and can mitigate fibrotic signalling by downregulating collagen production. In a murine model of full-thickness injury, topically-applied and photoactivated RB closed wounds faster than control and vehicle treatments and showed significantly improved wound healing outcomes, including enhanced early granulation, better collagen organisation and increased vascularity in the presence of protracted tissue ROS. These data support an overall improved cutaneous wound healing profile after RB phototherapy and warrant further investigations into this versatile molecule.