Autophagy plays a role in the prolongation of the lifespan of Caenorhabditis elegans by astaxanthin.

Astaxanthin, a xanthophyll belonging to the family of carotenoids, is a potent antioxidant. The effect of astaxanthin on longevity and its physiological and molecular mechanism are still unclear. In this study, we proved that astaxanthin could prolong the lifespan of Caenorhabditis elegans. To uncover whether astaxanthin delay aging by up-regulating autophagy, we assessed the expression of autophagy genes and found that the expression of autophagy genes was up-regulated after feeding with astaxanthin compared with the control group, and the difference was statistically significant. In order to explore the molecular mechanism of astaxanthin-induced autophagy upregulation, we knocked out the key genes daf-16 or hlh-30 of Insulin/IGF-1 signal pathway and target of rapamycin signal pathway (two common conservative signal pathways capable of regulating autophagy) by RNA interference, and the expression of autophagy gene lgg-1 decreased. Collectively, our results strongly suggest that autophagy, which is both the Insulin/IGF-1 signal pathway-dependent and target of rapamycin signal pathway-dependent, plays a role in the prolongation of the lifespan of Caenorhabditis elegans by astaxanthin.