Histochemically defined cell states during tail fin regeneration in teleost fishes

Abstract

Teleost fin rays regenerate when they are cut, forming a distal proliferating blastema that restores the entire structure in a few weeks. In the present study we have analysed the histochemical properties of the cells and the extracellular matrix of regenerating fins in two teleost species, Carassius auratus and Brachydanio rerio. Different cell types and states have been defined. Four epidermal cell types, i.e. peridermal, epidermal, basal epidermal and mucous cells, display different histochemical and lectin binding properties, depending on their distribution in the regenerative tissue. Blastema differentiates into two cell types: scleroblasts and fibroblasts. The scleroblasts stem from blastemal cells that have contacted the lateral palisade of actinotrichia and begun to release lepidotrichial material beneath the subepidermal basement membrane. The fibroblasts differentiate from blastemal cells in the centro-proximal region of the blastema. Both cell types pass through transient states. Blastemal cells showed increased affinities for Concanavalin agglutinin, Ricinus communis agglutinin, toluidine blue and aldehyde-fuchsin, as they differentiated into scleroblasts and fibroblasts. Three different regions are histochemically distinguishable in the precalcified lepidotrichial hemisegment, reflecting different degrees of maturation: mature matrix, central band and the peripheral (immature) region contacting scleroblasts. Maturation of lepidotrichial matrix is characterized by the lost of affinity for lectins and strong positivity for silver methenamine. A catalogue of position-dependent histochemical affinities defining cell diversity in the regenerating fin of teleosts is proposed in order to correlate changes with the underlying regeneration mechanisms.& b d y :

Bone patterning is altered in the regenerating zebrafish caudal fin after ectopic expression of sonic hedgehog and bmp2b or exposure to cyclopamine

“…Ectopic expression of N-shh and bmp2b resulted in additional bone deposition in the interray normally devoid of bone. However, excess bone was found only between the basal layer of the epidermis and the mesenchyme where the bone matrix-secreting scleroblasts are found (7,31). This effect depended on the distance between the amputation site (injection location) and origin of bifurcation, being maximal four to five segments above the origin of bifurcation and diminishing when DNA was injected further away.…”

Recovery of opercular anomalies in gilthead sea bream, Sparus aurata L.: morphological and morphometric analysis

“…Moreover, teleost fish and amphibians can fully regenerate largely severed appendages that include different tissues. Several studies on fin regeneration have been conducted in various teleost fish, including tilapia, trout and especially zebrafish Marí-Beffa, Santamaría, Fernandez-Llebrez & Becerra 1996;Poleo et al 2001;Santos-Ruiz et al 2002;Akimenko et al 2003;Poss, Keating & Nechiporuk 2003). In nature and in intensive-rearing conditions, opercular malformations as a rule cannot be attributed to traumatic events, but the restoration process could be regenerative-like.…”

Regeneration of caudal fin inPoecilia latipinna: Insights into the progressive tissue morphogenesis

“…Amongst vertebrates, teleost fish has emerged as an excellent model to study epimorphosis as it has remarkable capacity to regenerate multiple complex organs. Several teleost fish have been documented for their regenerative ability after fin injury that include Salaria pavo, 1 Tilapia melanopleura, Cyprinus carpio, Carassius auratus, [2][3][4] the zebrafish, Danio rerio, [5][6][7][8][9] and very recently Poecilia latipinna. 10,11 Although teleost can regenerate a variety of organs post-injury, caudal fin has been studied extensively due to the ease of doing invasive procedures.…”