Cicatrización de la piel de dorada (Sparus aurata L.)

Abstract

This doctoral thesis focuses on studying the wound healing process in gilthead seabream (Sparus aurata), a species of great economic importance in the Mediterranean. The research is divided into two parts: Part I (Chapters 1 and 2) focuses on the cellular study of cutaneous wound healing, establishing in vitro models to analyze the re-epithelialization process and the release of extracellular traps. On the other hand, Part II (Chapters 3 and 4) focuses on the use of natural products, such as skin injections or dietary supplements, with the aim of improving wound healing in gilthead seabream skin in vivo. Chapter 1 conducted microscopic and genetic studies of the wound healing process in gilthead seabream skin in vitro. The caudal fin skin explant model exhibits features of collective cell migration during the initial 3-day culture phase, characterized by the preservation of cell-cell junctions and directed cellular movement. The findings presented in this study provide compelling evidence of an Epithelial-Mesenchymal Transition (EMT) process occurring during a 7-day culture period of gilthead seabream caudal fin skin explants, making it a good in vitro model for wound healing studies. Chapter 2 investigated the formation of extracellular traps (ETs) by leukocytes from the head kidney of gilthead seabream. Different stimulants (Saccharomyces cerevisiae β-glucan (BG), Escherichia coli lipopolysaccharide (LPS), calcium ionophore A23187 (CaI), phorbol 12-myristate 13-acetate (PMA), and polyinosinic:polycytidylic acid (Poly I:C)) were used, and the release of ETs was observed, which are fibrous structures formed by DNA, histones, and antimicrobial proteins. All the stimulants used in this study induced the release of extracellular traps and myeloperoxidase activity by gilthead seabream head kidney leukocytes, and each stimulant generated a specific response, with PMA (500 ng/mL) being the most efficient after 1 hour of incubation. In addition, the extracellular traps released by gilthead seabream head kidney leukocytes exhibited associated myeloperoxidase activity. Chapter 3 evaluated the effects of short-chain fatty acids (SCFAs) on the inflammatory response in the skin. It was found that acetic acid was the most effective SCFA in reducing carrageenan-induced inflammation, suggesting its potential use as an anti-inflammatory agent in fish wound healing. Chapter 4 studied dietary supplementation with silk fibroin microparticles to improve wound healing in gilthead seabream skin. It was observed that the diet enriched with silk fibroin improved wound closure proportion and promoted cell proliferation, inflammatory phase, and expression of tissue repair-related genes. These findings suggest that silk fibroin could have therapeutic potential in improving wound healing in fish.