The Regenerative Capacity of the Zebrafish Caudal Fin Is Not Affected by Repeated Amputations

Abstract

BackgroundThe zebrafish has the capacity to regenerate many tissues and organs. The caudal fin is one of the most convenient tissues to approach experimentally due to its accessibility, simple structure and fast regeneration. In this work we investigate how the regenerative capacity is affected by recurrent fin amputations and by experimental manipulations that block regeneration.Methodology/Principal FindingsWe show that consecutive repeated amputations of zebrafish caudal fin do not reduce its regeneration capacity and do not compromise any of the successive regeneration steps: wound healing, blastema formation and regenerative outgrowth. Interfering with Wnt/ß-catenin signalling using heat-shock-mediated overexpression of Dickkopf1 completely blocks fin regeneration. Notably, if these fins were re-amputated at the non-inhibitory temperature, the regenerated caudal fin reached the original length, even after several rounds of consecutive Wnt/ß-catenin signalling inhibition and re-amputation.Conclusions/SignificanceWe show that the caudal fin has an almost unlimited capacity to regenerate. Even after inhibition of regeneration caused by the loss of Wnt/ß-catenin signalling, a new amputation resets the regeneration capacity within the caudal fin, suggesting that blastema formation does not depend on a pool of stem/progenitor cells that require Wnt/ß-catenin signalling for their survival.

Notch signaling coordinates cellular proliferation with differentiation during zebrafish fin regeneration

“…Masson's trichrome stainings were performed on paraffin wax-embedded sections as described previously (Azevedo et al, 2011) with the following modifications: 3.5 µm sections were washed with xylene, with decreasing concentrations of ethanol and with distilled water before incubation in Bouin's fixative (1 hour, 56°C). Collagen was stained using Aniline Blue solution with subsequent rinsing in distilled water and washing in 1% acetic acid solution.…”

“…The zebrafish tail fin regenerates completely and rapidly, and appears to have unlimited regenerative potential (Azevedo et al, 2011). The caudal fin consists of segmented bony fin rays built of two concave bones (the lepidotrichia) that are formed by osteoblasts lining the bone.…”

Yap control of tissue growth relies on cell density and F-actin in zebrafish fin regeneration

“…This indicates that a positional memory instructs the blastema cells according to their proximo-distal fin localization (Lee et al, 2005). Coupled to this property, the regenerative process occurs independently of the number of amputations applied and animal age (Azevedo et al, 2011). Such properties indicate a tight growth control program, involving precise coordination between proliferation and positional information along the regenerating caudal fin.…”

Wnt Signaling and Injury Repair

“…Perhaps most relevant to humans is the observation that across multiple species, regenerative capacity diminishes with age (reviewed in Silva and Conboy 2008; but see Eguchi et al 2011 for conflicting data). The inference from these observations is that aging depletes a stem cell population New data demonstrate that adult cells at the edges of the wound dedifferentiate to generate the new tissues (Straube et al 2004;Kragl et al 2009;Azevedo et al 2011). This feature is not unique to mammals: The wound blastema of an axolotl is composed of tissue-specific progenitor cells that arise from the partial dedifferentiation of neurons, cartilage, and muscle (Kragl et al 2009).…”