Abstract: The purpose of this study was to investigate the effect of crimson snapper scale peptides (CSSPs) on H2O2-induced oxidative damage in Caco-2 cells. The levels of lactate dehydrogenase (LDH) and interleukin-8 (IL-8) in the cell supernatant, the activity of intracellular antioxidant enzymes, the release of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), and the expression of apoptosis-related genes (Caspase-3, Caspase-9, Bax and Bcl-2) were measured. The antioxidant effects of CSSPs in intestinal cells were elucidated from the aspects of cellular redox state and apoptosis. Results showed that CSSPs mitigated H2O2-induced oxidative damage in Caco-2 cells through the antioxidant defense system. This effect involved increased activities of antioxidant enzymes and consequent inhibition of LDH release, intracellular ROS accumulation, and MDA and IL-8 production. Furthermore, CSSPs inhibited oxidative stress-induced apoptosis by regulating the mitochondrial apoptotic pathway, which significantly increased mitochondrial membrane potential, down-regulated the mRNA expression of Caspase-3, Caspase-9 and Bax, and up-regulated the mRNA expression of Bcl-2. In conclusion, CSSPs can effectively reduce the degree of cell damage by maintaining redox homeostasis and inhibiting apoptosis.

Key words: marine-derived peptides, antioxidant, Caco-2 cells, oxidative stress damage, cell apoptosis