AVOCADO PHYTOSTEROLS DECREASE UVB-INDUCED PRO-INFLAMMATORY MEDIATORS.

Exposure of skin to UVB radiation can cause the production of pro-inflammatory cytokines and prostanoids. Changes in the production of these mediators in the skin can decrease or increase the potentially damaging effects of UVB irradiation. In this series of experiments we investigated the effects of avocado-derived sterols on the production of pro-inflammatory mediators IL-1α, PGE-2, and IL-8 caused by UVB exposure. A thin film of the avocado lotion, or lotion base was applied to EpiDerm 24H prior to UVB exposure, and remained on the tissue for a maximum of 72H. At 12, 24, and 48H post-exposure, cells were sacrificed to determine viability, cytokine and prostaglandin production. Prior to UVB exposure treated and non-treated EpiDerm produced over 40 pg per ml IL-1α. At 12H post UVB exposure there was a complete suppression of IL-1α. By 48H post UVB exposure, there was a significant difference in the IL-1α levels in EpiDerm pretreated with the avocado lotion vs. those treated with either the lotion base or UVB alone (5 vs. 13 or 15 pg per ml, respectively). The production of PGE-2 was suppressed for both lotions at 12H. At 48H, there was no significant difference in the production of PGE-2 (250 pg per ml). IL-8 production was not completely suppressed 12H after UVB exposure. Twenty-four and 48H after exposure, the avocado lotion had a profound effect on IL-8 production compared to the lotion base or UVB alone (468 vs. 1242 or 1464 pg per ml, respectively). Interestingly, 48H after UVB exposure, IL-8 production by untreated control tissue and tissue treated with avocado lotion plus UVB was not significantly different. These data suggest that the addition of avocado-derived sterols to lotions may have long-term effects on chemokines produced by UVB induced inflammation. It is probable that avocado-derived sterols could be used to combat the severity of chronic inflammatory conditions such as atopic dermatitis and psoriasis by down regulating chemokine production, specifically IL-8, by damaged keratinocytes.

Atopic dermatitis, Avocado phytosterols, Avocado-derived sterols, EpiDerm, IL-1a, IL-8, Inflammation, Inflammatory, MTT, MTT ET-50 tissue viability assay, MTT assay, Non-cytotoxic, Non-phototoxic, Phototoxicity, Phytosterols, Pro-inflammatory, Psoriasis, UVA, UVB