OBJECTIVE To investigate the protective effect of collagen peptides from walleye pollock skin(CPWPS)in the hydrogen peroxide(H2O2)-induced oxidative stress damage model of the human keratinocyte cell line (HaCaT). METHODS HaCaT cells were pretreated with CPWPS 50,100 and 200 mg · L-1 for 12 h. Then H2O2 was added to the final concentration of 300μmol · L-1. After 12 h,the activity of catalase(CAT),glutathion peroxidase(GSH-Px),total superoxide dismutase(T-SOD)and total antioxidant capacity (T- AOC) were detected by enzymes and biochemical method. The expression of aquaporin3 (AQP3) in HaCaT cells was measured by Western blotting. RESULTS Compared with control group,CPWPS group did not exhibit significant cytotoxicity at a concentration up to 300 mg·L-1. The viability of cells treated with H2O2 300μmol·L-1 for 12 h decreased to 54.0%(P<0.01). The viability of cells pretreated with CPWPS 50,100 and 200 mg · L-1 for 12 h increased to 69.4%,79.4%and 89.1%(P<0.05,P<0.01),respectively. Compared with the model group,the activity of CAT,GSH-Px,T-SOD and T-AOC in HaCaT cells pretreated with CPWPS 50,100 and 200 mg·L-1 for 12 h increased. Compared with model group,the activity of CAT,GSH-Px,T-SOD and T-AOC of CPWPS 200 mg · L-1 pretreatment group increased by 56.90%,48.68%,48.24% and 71.43%(P<0.01),respectively. Western blotting revealed that the expression of AQP3 in H2O2 model group was in?creased relative to that in control group,while the expression of AQP3 in CPWPS pretreatment groups was decreased. The expression of AQP3 in CPWPS 200 mg · L-1 pretreatment group decreased to 67.1%(P<0.01) compared to the H2O2 model group. CONCLUSION CPWPS can protect HaCaT cells against H2O2- induced oxidative stress damage. The cytoprotective effects are associated with enhanced antioxidant capacity and decreased expression of AQP3.