Shvedova A A, Kisin E R, Murray A R, Kommineni C, Castranova V, Mason R P, Kadiiska M B, Gunther M R
National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA.
Chem Res Toxicol. 2002 Nov;15(11):1451-9. doi: 10.1021/tx0200313.
Organic peroxides are widely used in the chemical industry as initiators of oxidation for the production of polymers and fiber-reinforced plastics, in the manufacture of polyester resin coatings, and pharmaceuticals. Free radical production is considered to be one of the key factors contributing to skin tumor promotion by organic peroxides. In vitro experiments have demonstrated metal-catalyzed formation of alkoxyl, alkyl, and aryl radicals in keratinocytes incubated with cumene hydroperoxide. The present study investigated in vivo free radical generation in lipid extracts of mouse skin exposed to cumene hydroperoxide. The electron spin resonance (ESR) spin-trapping technique was used to detect the formation of alpha-phenyl-N-tert-butylnitrone (PBN) radical adducts, following intradermal injection of 180 mg/kg PBN. It was found that 30 min after topical exposure, cumene hydroperoxide (12 mmol/kg) induced free radical generation in the skin of female Balb/c mice kept for 10 weeks on vitamin E-deficient diets. In contrast, hardly discernible radical adducts were detected when cumene hydroperoxide was applied to the skin of mice fed a vitamin E-sufficient diet. Importantly, total antioxidant reserve and levels of GSH, ascorbate, and vitamin E decreased 34%, 46.5%. 27%, and 98%, respectively, after mice were kept for 10 weeks on vitamin E-deficient diet. PBN adducts detected by ESR in vitamin E-deficient mice provide direct evidence for in vivo free radical generation in the skin after exposure to cumene hydroperoxide.
有机过氧化物在化学工业中被广泛用作聚合物和纤维增强塑料生产、聚酯树脂涂料制造以及制药过程中的氧化引发剂。自由基的产生被认为是有机过氧化物促进皮肤肿瘤形成的关键因素之一。体外实验表明，在与氢过氧化异丙苯孵育的角质形成细胞中，金属催化形成了烷氧基、烷基和芳基自由基。本研究调查了暴露于氢过氧化异丙苯的小鼠皮肤脂质提取物中的体内自由基生成情况。采用电子自旋共振（ESR）自旋捕获技术，在皮内注射180 mg/kg α-苯基-N-叔丁基硝酮（PBN）后，检测PBN自由基加合物的形成。结果发现，局部暴露30分钟后，12 mmol/kg的氢过氧化异丙苯在维生素E缺乏饮食喂养10周的雌性Balb/c小鼠皮肤中诱导了自由基的产生。相比之下，当将氢过氧化异丙苯应用于喂食充足维生素E饮食的小鼠皮肤时，几乎检测不到明显的自由基加合物。重要的是，在维生素E缺乏饮食喂养小鼠10周后，总抗氧化储备以及谷胱甘肽、抗坏血酸和维生素E的水平分别下降了34%、46.5%、27%和98%。通过ESR在维生素E缺乏小鼠中检测到的PBN加合物为暴露于氢过氧化异丙苯后皮肤中体内自由基的产生提供了直接证据。
