Cell proliferation and movement during early fin regeneration in zebrafish

Abstract

Cell proliferation and cell movement during early regeneration of zebrafish caudal fins were examined by injecting BrdU and Di-I, respectively. In normal fins of adult fish, a small number of proliferating cells are observed in the epidermis only. Shortly following amputation, epithelial cells covered the wound to form the epidermal cap but did not proliferate. However, by 24 hr, epithelial cells proximal to the level of amputation were strongly labeled with BrdU. Label incorporation was also detected in a few mesenchymal cells. Proliferating cells in the basal epithelial layer were first observed at 48 hr at the level of the newly formed lepidotrichia. At 72 hr, proliferating mesenchymal cells were found distal to the plane of amputation whereas more proximal labeled cells included mainly those located between the lepidotrichia and the basal membrane. When BrdU-injected fins were allowed to regenerate for longer periods, labeled cells were observed in the apical epidermal cap, a location where cells are not thought to proliferate. This result is suggestive of cell migration. Epithelial cells, peripheral to the rays or in the tissue between adjacent rays, were labeled with Di-I and were shown to quickly migrate towards the site of amputation, the cells closer to the wound migrating faster. Amputation also triggered migration of cells of the connective tissue located between the hemirays. Although cell movement was induced up to seven segments proximal from the level of amputation, cells located within two segments from the wound provided the main contribution to the blastema. Thus, cell proliferation and migration contribute to the early regeneration of zebrafish fins.

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

“…The lepidotrichia are composed of two segmented hemirays that bifurcate periodically along their proximal-distal axis forming sister-ray branches. After amputation, epithelial cells migrate from the stump to cover the wound region (7,8), beneath which a blastema containing undifferentiated proliferative mesenchymal cells forms (1). Scleroblasts then differentiate within the blastema at the epithelial͞mesenchymal interface and begin to secrete the matrix that will form the new dermal bone.…”

Influence of indomethacin on the regenerative process of the tail fin of teleost: morphometric and ultrastructural analysis

“…Fin regeneration can be summed up into four stages (Poss et al, 2000b): firstly, epidermic cells migrate to cover the wound and form a multistratificated layer; secondly, the mesenchymal tissue between both hemisegments located right beneath the epidermal layer suffers a disorganisation and an undifferentiation and, mesenchymal cells migrate distally in the direction of the amputation (Poleo et al, 2001); thirdly, these cells accumulate to form the blastema, a tissue mass through which new structures of the fin are derived; and finally, the regeneration is complete on the growing phase, composed of an intensively integrated proliferation, differentiation and restoration (Poss et al, 2002).…”

Impaired caudal fin‐fold regeneration in zebrafish deficient for the tumor suppressor Pten

“…Initially, remaining cells from the dorsal and ventral side of the caudal fin‐fold migrate over the amputation plane to form the wound epithelium (Poleo et al., 2001). This results in the formation of an apical epidermal cap, which signals for the dedifferentiation of cells to form the distal blastema.…”

“…The mechanism of embryonic caudal fin‐fold regeneration is the same as adult caudal fin regeneration. Following injury, nearby cells migrate to cover the wound and form an apical epidermal cap that is essential to initiate blastema formation and regenerative outgrowth (Poleo, Brown, Laforest, & Akimenko, 2001). To date, many genes have been implicated in the regenerative process (Padhi et al., 2004) and multiple signaling pathways have been validated to be essential for regeneration, including fibroblast growth factor, sonic hedgehog, bone morphogenetic protein, Wnt, and Notch (Gemberling, Bailey, Hyde, & Poss, 2013).…”