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

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), <i>Acanthaster planci</i>, 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 <i>cxcl8-l1</i> 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.