# Extract from crown-of-thorns starfish promotes zebrafish caudal fin regeneration by inhibition of neutrophil migration

## TL;DR

A substance from crown-of-thorns starfish helps zebrafish regrow their tails by stopping neutrophils from moving to the injury site.

## Contribution

The study identifies a starfish extract that promotes zebrafish regeneration by inhibiting neutrophil migration.

## Key findings

- The water-eluted fraction (TWE) from COTS contains saponins and promotes zebrafish caudal fin regeneration.
- TWE reduces cxcl8-l1 expression in tail tissue, inhibiting neutrophil migration.
- Modulating neutrophil responses with TWE may enhance tissue regeneration in zebrafish.

## Abstract

Reparative regeneration is the process of repairing or replacing damaged or lost tissue. Starfish possess remarkable regenerative capacity and can regenerate nearly any part of their body, making them ideal models for studying regenerative medicine. In this study, we isolated four different extracts from crown-of-thorns starfish (COTS), Acanthaster planci, which recently experienced outbreaks in the South China Sea and pose a threat to the coral reef ecosystem. Our study found that one extract, the water-eluted fraction (TWE), which was proved to contain saponins by physical, chemical and spectroscopic identification, significantly promoted zebrafish larvae caudal fin regeneration. We further revealed that TWE inhibits neutrophil migration by reducing the expression of cxcl8-l1 in the tail tissue, thereby promoting caudal fin regeneration. Our results suggested that TWE may directly or indirectly enhance reparative regeneration in zebrafish by modulating neutrophil responses.