The human body is amazing, but cannot hold a candle to many organisms when it comes to limb regeneration. Zebrafish are able to regenerate amputated fins, including the sensory axons in the fin that sense touch. Today’s image is from a paper discussing the signals required for this process.
When tissue is regenerated, there are several different cell types that must be involved in order to heal the entire tissue. A recent paper looks at the regeneration of skin cells and sensory neuron axons in zebrafish to determine how the process of wound healing requires the coordination of several cell types. Zebrafish larvae can regenerate both the skin tissue and sensory axons of an amputated tail fin, and Rieger and Sagasti found that the reactive oxygen species hydrogen peroxide (H2O2) plays an important role in this coordination. Injured skin cells release the H2O2 signal, and this signal then promotes robust regeneration of the sensory axons. Images above show the sensory axons in uninjured (top) and amputated (bottom) tail fins over time. Axons were regenerated into the amputated region (dotted line, shaded region), as seen as the red trajectories of axon tips (left-most image). Rieger, S., & Sagasti, A. (2011). Hydrogen Peroxide Promotes Injury-Induced Peripheral Sensory Axon Regeneration in the Zebrafish Skin PLoS Biology, 9 (5) DOI: 10.1371/journal.pbio.1000621