Scale calcification in the goldfish in vitro: histological and quantitative analysis

Abstract

The external layer of a teleost fish scale is composed of type I collagen, an amorphous matrix substance and hydroxyapatite crystals. Calcification of this layer can be inhibited in the scale regenerating process under a calcium and phosphate deficient (CaDPD) condition, and can be facilitated by incubation in physiological saline. The aim of this study was to evaluate this model of calcification using histological and quantitative analysis in order to promote further understanding of the mechanism of calcification in fish scales.We found that the external layer of the scales produced under a CaDPD condition contained more densely-aligned collagen fibrils with a small amount of the amorphous matrix substance. The CaDPD scale contained only one-third of the amount of calcium and phosphate present in the control fish. After 4-hour incubation, a 2-3-fold increase in calcium content and a 1.5-fold increase in phosphate content were observed.Calcification proceeded in the external layer, and mineral deposits grew only in the electron-dense matrix substance. We conclude that this model would be suitable to study the early process of fish scale calcification that occurs in the non-collagenous substance. The electron-dense substance may contain key molecules that promote calcification. 194/ 200 word

Chronic stress impairs the local immune response during cutaneous repair in gilthead sea bream (Sparus aurata, L.)

“…Cutaneous repair following scale removal involved morphological modifications similar to what was reported in gilthead sea bream (Costa et al, 2017;Vieira et al, 2011), sea bass (Guerreiro et al, 2013) and other teleosts (Ogawa et al, 2010;Ohira et al, 2007;Quilhac & Sire, 1999). No major histological and histomorphometric modifications were seen between control and chronically stressed fish in both regenerated and undamaged skin.…”

Zebrafish (Danio rerio) in calcium-poor water mobilise calcium and phosphorus from scales

“…restriction via the water and/or diet) or increased demand (e.g. during oogenesis and vitellogenesis), calcium is predominantly mobilized from the scale compartment, rather than from endoskeletal bone (Mugiya and Watabe, 1977;Takagi et al, 1989;Persson et al, 1997Persson et al, , 1998Ogawa et al, 2010). This indicates that scales indeed constitute a dynamic calcium pool.…”

Short‐term homeostatic regulation of blood/interstitial fluid Ca2+ concentration by the scales of anadromous sea trout Salmo trutta L. during smoltification and migration

“…Like bone, teleost scales contain mineralized hydroxyapatite (a mineral form of calcium apatite Ca10(PO4)6OH2) and collagen-based matrix components (Waterman, 1970;Meunier, 1984;Sire et al, 1997;Ogawa et al, 2010;De Vrieze et al, 2011), as well as populations of different cell types that play a key role in their development, maintenance, regeneration, and physiology (Sire, 1989;Pasqualetti et al, 2012a;Metz et al, 2014). The mainly anterior episquamal surface of sea trout scales exhibit concentric hydroxyapatite ridges called circuli that radiate out from the focus, which is in a slightly more posterior location (Elliot and Chambers, 1996;Ryan et al, 2019).…”