EFFECT OF SQUALENE ON SUPEROXIDE ANION GENERATION INDUCED BY A SKIN IRRITANT, LAUROYLSARCOSINE

The effect of squalene on superoxide anion (O-2(-)) generation was studied in rats in order to elucidate the mechanism whereby the compound decreases erythema induced by 1% lauroylsarcosine (LS) ointment. Topical application of superoxide dismutase (SOD) ointment (99000 U/g) was effective on the erythema as well as 10% squalene ointment, suggesting that O-2(-) is a major mediator responsible for skin irritation. LS (200-400 mu g/ml) caused overt production of O-2(-) from cultured keratinocytes and peritoneal exudate leukocytes; O-2(-) was significantly reduced by addition of squalene (100 mu g/ml). A similar response was observed with zymosan-induced O-2(-) generation. However, squalene had no effects on O-2(-) generation in a xanthine-xanthine oxidase system unlike the effect observed with SOD. These results suggest that a possible role of squalene for the alleviation of skin irritation is suppression of O-2(-) production depending on the different mechanism of action from SOD.