Hypertrophic scar is a common problem after skin burns or trauma which brings physical, psychological, and cosmetic problems to patients. Photodynamic therapy with 5-aminolevulinic acid (5-ALA) is a promising therapy for hypertrophic scar. However, clinical applications of 5-ALA are limited because of the low permeability of 5-ALA in the skin stratum corneum and the rapid binding of protoporphyrin IX (PpIX) with iron ions, which lead to insufficient PpIX production in target tissues. Herein, a mixture of 5-ALA and DFO (deferoxamine, a special iron chelator) was applied for the treatment of hypertrophic scar. 5-ALA/DFO could efficiently block the biotransformation of PpIX to heme, thus realizing a significant accumulation of photosensitizer. In addition, injection locally into the lesion was applied, which combined with enhanced photodynamic therapy to destroy hypertrophic scar fibroblasts. In vitro experiments showed that 5-ALA/DFO could increase more ROS generation by increasing the accumulation of PpIX, resulting in the apoptosis of hypertrophic scar fibroblasts. Furthermore, 5-ALA/DFO inhibited the proliferation and migration of hypertrophic scar fibroblasts. In vivo study showed that 5-ALA/DFO could effectively inhibit the formation of proliferative scar. Therefore, 5-ALA/DFO has the potential to enhance the photodynamic therapy of 5-ALA and provides a new treatment strategy for hypertrophic scar.

增生性疤痕是皮肤烧伤或外伤后常见的问题，给患者带来身体、心理和美容方面的问题。5-氨基乙酰丙酸 (5-ALA) 的光动力疗法是治疗增生性疤痕的一种很有前途的疗法。然而，由于5-ALA在皮肤角质层的渗透性低，原卟啉IX （PpIX）与铁离子快速结合，导致靶组织PpIX生成不足，5-ALA的临床应用受到限制。在此，应用 5-ALA 和 DFO（去铁胺，一种特殊的铁螯合剂）的混合物来治疗增生性瘢痕。5-ALA/DFO 可有效阻断 PpIX 向血红素的生物转化，从而实现光敏剂。此外，局部注射到病灶处，结合增强的光动力疗法来破坏增生性瘢痕成纤维细胞。体外实验表明，5-ALA/DFO 可通过增加 PpIX 的积累来增加更多 ROS 的产生，从而导致增生性瘢痕成纤维细胞凋亡。此外，5-ALA/DFO 抑制增生性瘢痕成纤维细胞的增殖和迁移。体内研究表明，5-ALA/DFO能有效抑制增生性瘢痕的形成。因此，5-ALA/DFO具有增强5-ALA光动力疗法的潜力，为增生性瘢痕提供了一种新的治疗策略。