Dennis K J, Shibamoto T
Photochem Photobiol. 1989 May;49(5):711-6. doi: 10.1111/j.1751-1097.1989.tb08445.x.
Malonaldehyde (MA), a product of lipid peroxidation, is known to have a number of toxicological effects. Among skin surface components, squalene has been suggested as a significant source of MA following UV exposure. Irradiation of squalene coated on the inside surface of glass tubes served as a simple model to examine skin surface photochemistry. Malonaldehyde produced during UV-irradiation was reacted with methyl hydrazine to form N-methylpyrazole, which was then measured by gas chromatographic analysis. Ultraviolet A-irradiation produced low levels of MA from squalene, with a maximum of 1.0 nmol MA/mumol squalene near 6 h. Malonaldehyde production varied with the energy of irradiation, with levels of 176 nmol/mg squalene and 9 nmol/mg squalene produced after 3 h of irradiation with UVB and UVA, respectively. The thiobarbituric acid (TBA) assay for lipid peroxidation showed large overestimations of MA levels under all irradiation conditions tested. The TBA assay predicted the highest levels of MA with UVC but we did not detect any MA with our assay.
丙二醛（MA）是脂质过氧化的产物，已知具有多种毒理学效应。在皮肤表面成分中，角鲨烯被认为是紫外线照射后MA的重要来源。照射涂覆在玻璃管内表面的角鲨烯可作为一个简单模型来研究皮肤表面光化学。紫外线照射过程中产生的丙二醛与甲基肼反应生成N-甲基吡唑，然后通过气相色谱分析进行测定。紫外线A照射从角鲨烯产生的MA水平较低，在6小时左右时最高可达1.0 nmol MA/μmol角鲨烯。丙二醛的产生随照射能量而变化，用UVB和UVA照射3小时后，分别产生176 nmol/mg角鲨烯和9 nmol/mg角鲨烯的MA水平。用于脂质过氧化的硫代巴比妥酸（TBA）测定法在所有测试的照射条件下都显示出对MA水平的大幅高估。TBA测定法预测UVC照射时MA水平最高，但我们的测定法未检测到任何MA。
