Enteric nervous system can regenerate in zebrafish larva via migration into the ablated area and proliferation of neural crest-derived cells

Enteric nervous system (ENS) which is derived from neural crest is essential for gut function and its deficiency causes severe congenital diseases. Since capacity of ENS regeneration in mammals is limited, additional complimentary models would be useful. Here, we show that the ENS in zebrafish larva at 10-15 days post-fertilization is highly regenerative. The number of enteric neurons (ENs) recovered to ∼50% of the control by 10 days post-ablation (dpa) after their laser ablation. Using transgenic lines in which enteric neural crest-derived cells (ENCDCs) and ENs are labeled with fluorescent proteins, we live-imaged the regeneration process, and found covering by neurites extended from the unablated area and entry of ENCDCs in the ablated areas by 1-3 dpa. BrdU assay suggested that ∼80% of the ENs and ∼90% of the Sox10-positive ENCDCs therein at 7dpa are generated through proliferation. Thus the ENS regeneration involves proliferation, entrance and neurogenesis of ENCDCs. This is the first report regarding the regeneration process of the zebrafish ENS; our findings provide a basis for further in vivo research at single-cell resolution in the vertebrate.