Abstract: Objective: To determine whether the prokaryotic expression product of the red rice OsPrx3 gene, which encodes a peroxiredoxin, can enhance oxidative stress resistance in animals. Methods: OsPrx3 was cloned and expressed in Escherichia coli. After ingestion of the target protein, the animal model Caenorhabditis elega was evaluated for its motility, body length, oxidative stress resistance, reactive oxygen species (ROS) and fat contents, and oxidation-related gene expression levels. Results: This gene was cloned and expressed in E. coli successfully, and the purified expressed protein had high antioxidant activity, which at 1 μg/mL scavenged more than 40% of H2O2 in five minutes. Ingestion of the target protein significantly increased the resistance to oxidative stress within 15 minutes after oxidative treatment and reduced ROS and cellular lipid content in C. elegans compared to the control group, although there were no significant changes in motility or body length. Additionally, the expression levels of several critical antioxidant genes were evidently increased in the treated C. elegans. Conclusion: The OsPrx3 protein had high in vitro antioxidant potency, and when ingested by C. elegans, significantly enhanced the resistance to oxidative stress.

Key words: peroxiredoxin; red rice; Caenorhabditis elegans; antioxidant activity