Phloroglucinol-combined photobiomodulation for minimizing burn-induced skin fibrosis

Fibrosis is a prevalent problem that pathologically accompanies chronic inflammatory diseases. Despite the availability of various fibrosis treatments, therapeutic efficacy must be further improved to achieve better clinical outcomes. The purpose of this study is to develop a novel treatment by combining phloroglucinol (PHL) with photobiomodulation (PBM) to prevent skin fibrosis. In in vitro, 635 nm PBM at 8 J/cm2 significantly reduced TNF-alpha levels, and 100 μg/ml of PHL suppressed the expression of α-smooth muscle actin and type I collagen due to the downregulation of SMAD 2/3 and MAPK signaling pathways. The 1470 nm laser light created the initial wound (97.1 mm2), leading to scar formation after complete wound closure (21 days) on rodent skin. In comparison to other groups, the dual treatment accelerated wound closure and achieved rapid and complete healing in 17 days. Histological analysis presented the reduced fibrotic scar and collagen deposition in the dual treatment group. PHL-combined PBM treatment enhanced the anti-inflammatory effect by 36% in comparison to single treatment groups. Overall, the proposed combined treatment promoted wound healing and enhanced anti-inflammatory and anti-fibrotic effects in the overexpressed in vitro and in vivo models.