Abstract: Objective: To investigate the repairing effects of sturgeon liver metallothionein (MT) on ultraviolet (UV) radiation-induced damage in Caenorhabditis elegans. Methods: MT was prepared from hybrid sturgeon liver through extraction with a Tris-HCl buffer solution (0.04 mol/L, pH 8.0) in a water bath at 50 ℃, followed by heat treatment at 80 ℃ and freeze-drying. The repairing effects on UV radiation-induced damage in C. elegans were explored by measuring changes in nematode lifespan, head thrashing frequency, body bending frequency, and antioxidant enzyme activities. In order to infer the underlying mechanism, quantitative polymerase chain reaction (PCR) was performed to analyze gene expression changes. Results: MT at concentrations of 0.3, 0.4, and 0.5 mg/mL significantly alleviated UV-induced reduction in lifespan and locomotion, effectively increasing the levels of superoxide dismutase (SOD) and catalase (CAT), reducing malondialdehyde (MDA) content, and lowering the levels of reactive oxygen species (ROS) and lipofuscin. Furthermore, MT down-regulated the expression of daf-2, age-1, pdk-1, and akt-1, while up-regulating the expression of daf-16 and skn-1. Conclusion: Sturgeon liver metallothionein effectively repairs UV-induced damage in C. elegans, likely by activating the insulin/IGF-1 signaling pathway, upregulating the expression levels of SOD and CAT, thereby scavenging ROS and promoting cellular repair.

Key words: sturgeon; metallothionein; Caenorhabditis elegans; repair of ultraviolet-induced damage