Ozone-Exposure Depletes Vitamin E and Induces Lipid Peroxidation in Murine Stratum Corneum

Abstract

The presence of ozone (O(3)) in photochemical smog is an important health concern. We hypothesized that the stratum corneum (SC), as the outermost skin layer and the permeability barrier of the skin, represents a sensitive target for O(3)-induced oxidative stress. To test this hypothesis, SKH-1 hairless mice were anesthetized and exposed for 2 h to O(3) by using two strategies: (i) single exposures to 0 (n = 12), 1 (n = 4), 5 (n = 4), and 10 (n = 4) ppm; and (ii) repeated daily exposures to 0 ppm (controls; n = 4) and 1 ppm (n = 4) for six consecutive days. New techniques based on the removal of SC by tape stripping were used to analyze the biologic effects of O(3) with respect to vitamin E depletion and lipid peroxidation. SC tissue was extracted from the tape and immediately analyzed by HPLC for vitamin E and malondialdehyde (MDA) concentrations. After in vivo exposure to increasing O(3) doses, vitamin E was depleted and MDA formation was increased, both in a dose-dependent manner. Remarkably, repeated low-level O(3) exposures resulted in cumulative oxidative effects in the SC: As compared with O(3) exposures of 0 ppm (alpha-tocopherol, 8.95 +/- 1.3 pmol per mg; gamma-tocopherol, 3.00 +/- 0.3 pmol per mg; MDA, 3.69 +/- 0.3 pmol per mg), vitamin E was depleted (alpha-tocopherol, 2.90 +/- 0.6 pmol per mg, p < 0.001; gamma-tocopherol, 0.5 +/- 0.1 pmol per mg, p < 0.001) and MDA levels were increased (4.5 +/- 0.2; p < 0.01). This report demonstrates the unique susceptibility of the SC to oxidative damage upon exposure to O(3).

Reactions of ozone with human skin lipids: Sources of carbonyls, dicarbonyls, and hydroxycarbonyls in indoor air

“…This conclusion is supported by the product analysis reported above (further details, including estimated yields, are in SI Text) and stands in contrast to earlier reports that have focused on vitamin E and other less abundant antioxidants as ozone scavengers (14-16) and malondialdehyde as a prominent ozonolysis product (14).…”

“…The single most abundant ozone-reactive constituent is squalene [10 to 12% of the surface lipids (13)]. Other "antioxidants" present in the stratum corneum can react with ozone, including ascorbic acid (vitamin C), tocopherols and tocotrienols (vitamin E), cholesterol, ubiquinones (coenzyme Q), glutathione, and uric acid (14)(15)(16). However, these are much less abundant than squalene and unsaturated fatty acid moieties in their free or esterified forms (17).…”

Vernix Caseosa in Neonatal Adaptation

“…Thiele et al 17,34 have reported the presence of vitamin E in the epidermis and SC and that sebaceous secretion is a major mechanism for its delivery to the skin surface. Exposure to UVA, UVB and ozone results in reduction of vitamin E. 34,35 Gerloczy et al 36,37 first reported vitamin E in vernix over 40 years ago at amounts from trace levels to 90 mg/g wet weight (0.21 mmole/g wet weight), comparable to levels in high vitamin E organs.…”

“…Exposure to UVA, UVB and ozone results in reduction of vitamin E. 34,35 Gerloczy et al 36,37 first reported vitamin E in vernix over 40 years ago at amounts from trace levels to 90 mg/g wet weight (0.21 mmole/g wet weight), comparable to levels in high vitamin E organs. We found a mean vitamin E content of 13.2 to 18.9 mg/g wet weight of vernix (0.031 to 0.044 mmole/g wet weight).…”

Potential Use of Spin Traps to Control ROS in Antipollution Cosmetics—A Review

“…The cytotoxicity of ozone is due to its capability of antioxidant depletion [63][64][65] and its interaction with unsaturated lipids to generate damaging free radicals or toxic intermediate products [66]. Ozone exposure can influence antioxidant levels and oxidation markers in the outermost stratum corneum layer [67,68].…”