Salmon cartilage proteoglycan promotes the healing process of Staphylococcus aureus-infected wound

Wound healing is the critical event for maintaining skin function and barrier. Inflammatory state in which a variety of cells are activated and accumulated is important for wound healing. Bacterial infection in cutaneous wound is a common problem and causes delay of wound healing. Our previous study demonstrated that the salmon nasal cartilage proteoglycan (PG) has an immunomodulatory effect in various mouse models of inflammatory disease. In this study, we investigated the effect of PG on healing process of Staphylococcus aureus-infected wound. PG accelerated wound closure in the initial phase of both infected and non-infected wound healing. In addition, the bacterial number in wounds of the PG-treated mice was significantly lower than that in the vehicle group. Neutrophil and macrophage infiltration was intensively observed in the PG-treated mice on day 2 after S. aureus inoculation, whereas neutrophil and macrophage influx was highly detected on day 6 in the vehicle control. Moreover, the production of TGF-β and IL-6 in the wound tissue was significantly promoted compared to the vehicle control on day 1. In contrast, the production of IL-1β and TNF-α in PG-treated mice was significantly decreased compared to the vehicle control on day 5. These data suggested that PG modulates the inflammatory state in infected wounds leading to promote wound healing.