Substance-P and transforming growth factor-β in chitosan microparticle-pluronic hydrogel accelerates regenerative wound repair of skin injury by local ionizing radiation

Clinical irradiation therapy for cancer could increase the risk of localized wound complications. This study was conducted to evaluate the potential use of a chitosan microparticle-pluronic F127 (CSMP-PF) hydrogel complex containing bioactive molecules, substance P and transforming growth factor-beta 1, to regeneratively repair skin damaged by local ionizing radiation (IR). The BALB/c/bkl mice were locally irradiated to their limbs with a single 40 Gy dose of Co-60 gamma rays to induce a skin injury. The morphological characteristics of the chitosan microparticles were analysed by scanning electron microscopy. The amounts of bioactive molecules taken up and released by the CSMP-PF hydrogel complex were measured. Haematoxylin and eosin staining of IR-damaged skin showed acanthosis and hyperkeratosis in the epidermis; and damage to hair follicles/skin appendages and adipose tissue, as well as panniculus carnosus, in the dermis. Injection of the CSMP-PF hydrogel complex into IR-damaged skin resulted in skin repair, suggesting that the complex has potential for use in the regenerative repair of IR-damaged skin.