Squalene but not n-3 fatty acids protect against hydrogen peroxide-induced sister chromatid exchanges in Chinese hamster V79 cells

Abstract

Fish-oil derived n-3 PUFA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has been shown to exhibit anti-carcinogenic effects in vivo and in vitro. Squalene, found in shark liver oil and olive oil, can effectively inhibit chemically induced tumorigenesis in rodents. The aim of the present study was to investigate whether supplementation with EPA (50 μmol/l), DHA (50 μmol/l) or squalene (50 μmol/l) for 24 h would protect Chinese hamster V79 fibroblast cells against oxidant-induced DNA damage. EPA and DHA were delivered to the cells either complexed to bovine serum albumin (BSA) or dissolved in ethanol. DNA damage was assessed using the sister chromatid exchange (SCE) assay. V79 cells exposed to hydrogen peroxide (H 2O 2) alone showed a significant increase in SCE ( P < 0.05) when compared with control levels. Pre-incubation with either EPA or DHA did not significantly affect H 2O 2-induced SCE regardless of the delivery vehicle employed. However, pre-treatment with squalene significantly decreased the frequency of SCE induced by H 2O 2 ( P < 0.05). Results indicate that squalene was more effective than EPA and DHA in protecting against H 2O 2-induced SCE.