Expression and activity levels of chymase in mast cells of burn wound tissues increase during the healing process in a hamster model

Abstract

Abstract. The present study aimed to investigate the changes in the expression levels and activity of mast cell chymase in the process of burn wound healing in a hamster model of deep second-degree burn. The hamster model was established by exposing a ~3 cm diameter area of bare skin to hot water (75˚C) for 0, 6, 8, 10 or 12 sec. Tissue specimens were collected 24 h after burning and histological analysis revealed that hot water contact for 12 sec was required to produce a deep second-degree burn. Quantitative polymerase chain reaction and a radioimmunoassay were used to the determine changes in chymase mRNA expression levels and activity. The mRNA expression levels and activity of chymase were increased in the burn wound tissues when compared with the normal skin. However, no statistically significant differences were observed in mast cell chymase activity amongst the various post-burn stages. Chymase mRNA expression levels peaked at day 1 post-burn, subsequently decreasing at days 3 and 7 post-burn and finally increasing again at day 14 post-burn. In summary, a hamster model of deep second-degree burn can be created by bringing the skin into contact with water at 75˚C for 12 sec. Furthermore, the mRNA expression levels and activity of chymase in the burn wound tissues increased when compared with those in normal skin tissues. IntroductionSkin wound healing is a complex multifactorial process, involving inflammation, cell proliferation, cell migration, re-epithelialization, angiogenesis, extracellular matrix deposition and remodeling (1,2). Burn wounds have a long healing period, and are the most representative persistent wounds for use in the study of skin wound healing. Deep second-degree burn wounds exhibit spontaneous epithelial regeneration through the proliferation and migration of the skin appendages under the wound and the epidermal cells around the wound margin (3). The healing period is relatively long; thus, deep second-degree burns are useful for the experimental study of burn wounds. Animal models of burn wounds have been used to study various pathological changes and healing mechanisms involved in the burn wound healing process (4).Burn-induced tissue ischemia and inflammation can increase the number of mast cells in burn tissues (5) and stimulate mast cells to release vasoactive substances by degranulation (6). Mast cells play a role in the acute inflammatory phase and participate in wound healing together with fibroblasts (7,8). Once activated, mast cells degranulate and release histamine, heparin and a variety of enzymes, such as chymase, cathepsin G and hydroxy peptidase A (9). Chymase is closely associated with tissue fibrosis.Chymase is an α-chymase-like serine protease that is involved in numerous physiological and pathophysiological processes. One of the most important functions of chymase is the regulation of angiotensin (Ang)II generation. In addition, chymase promotes myocardial and skin fibroblast proliferation (10,11), the release of transforming growth factor-β1 bound to the extracel...

The Dynamics of the Skin’s Immune System

“…Deletion of mast cells reduces tissue damage in a second-degree scald burn injury model in mice [477]. Interestingly, their numbers are shown to increase after burn injury and reach their peak at later stages, suggesting they may also be involved in the proliferative phase [478]. It is suggested that mast cells promote tissue repair and remodeling during the later stages of burn wound healing [478,479].…”

“…Interestingly, their numbers are shown to increase after burn injury and reach their peak at later stages, suggesting they may also be involved in the proliferative phase [478]. It is suggested that mast cells promote tissue repair and remodeling during the later stages of burn wound healing [478,479]. However, uncontrolled mast cell activity has been associated with fibrosis and scar formation [57,480].…”

Effects of ginsenoside Rb1 on second-degree burn wound healing and FGF-2/PDGF-BB/PDGFR-β pathway modulation

“…Second-degree burns affect the epidermis and some parts of the dermis [ 2 ]. Therefore, second-degree burn wound healing is a complex multifactorial process involving inflammation, proliferation, re-epithelization, and remodeling phases [ 3 , 4 ]. The stages overlap, and each involves the joint participation of diverse repair cells, inflammatory cells, growth factors, and extracellular matrix components, including fibroblast growth factor (FGF)-2, platelet-derived growth factor (PDGF), and other burn-related growth factors [ 5 – 7 ].…”

Role of Inducible Nitric Oxide Synthase and Interleukin-6 Proteins Expression in Estimation of Skin Burn Age and Vitality: Immunohistochemical Study in Rat

“…To study the age and vitality of burn injury, inflammatory mediators or cells and matrix proteins in injured tissue could be analyzed (Dong et al, 2015).Nitric oxide (NO) plays a crucial role as a signal molecule in the healing process of skin burn (Lakshmi et al, 2011).It is synthesized during the conversion of L-arginine to L-citrulline by the action of nitric oxide synthase (NOS) family of enzymes (Speranza et al, 2012).…”