Wang Shuguang, Sheng Yinghong, Feng Manliang, Leszczynski Jerzy, Wang Lei, Tachikawa Hiroyasu, Yu Hongtao
Department of Chemistry, Jackson State University, Jackson, MS 39217, USA.
Environ Toxicol. 2007 Jun;22(3):318-27. doi: 10.1002/tox.20241.
The photocytotoxicity of 16 polycyclic aromatic hydrocarbons (PAHs) on the priority pollutant list of the United States Environmental Protection Agency (US EPA) were tested in human skin HaCaT keratinocytes. A selected PAH was mixed with HaCaT cells and irradiated with a solar simulator lamp for a dose equivalent to 5 min of outdoor sunlight and the cell viability was determined immediately and also after 24 h of incubation. For the cells without incubation after the treatments, it is found that all PAHs with three rings or less, except anthracene, are not photocytotoxic, while the four or five-ring PAHs (except chrysene), benz[a]anthracene, dibenzo[a,h]anthracene, benzo[ghi]perylene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, benzo[b]fluorenthene, fluorenthene, and pyrene, are photocytotoxic to the human skin HaCaT keratinocytes. If the cells were incubated for 24 h after the treatments, the photocytotoxic effect of the PAHs was greatly amplified in comparison to the nonincubated cells. For the 24 h incubated cells, all PAHs except naphthalene exhibit photocytotoxicity to some extent. Exposure to 5 microM of the 4- and 5-ring PAHs (except chrysene) and 3-ring anthracene more than 80% of the cells lose viability. The photocytotoxicity of the PAHs correlates well with several of their excited state properties: light absorption, excited singlet-state energy, excited triplet-state energy, and HOMO-LUMO energy gap. All the photocytotoxic PAHs absorb light at >300 nm, in the solar UVB and UVA region. There is a threshold for each of the three excited state descriptors of a photocytotoxic PAH: singlet energy <355 kJ/mol (corresponding to 337 nm light), triplet energy <230 kJ/mol (corresponding to 520 nm light), HOMO-LUMO gap <3.6 eV (corresponding to 344 nm light) obtained at the Density Functional Theory B3LYP/6-31G(d) level.
在美国环境保护局（US EPA）的优先污染物清单上的16种多环芳烃（PAHs）的光细胞毒性在人皮肤HaCaT角质形成细胞中进行了测试。将一种选定的PAH与HaCaT细胞混合，并用太阳模拟器灯照射，剂量相当于5分钟的户外阳光照射，然后立即以及在孵育24小时后测定细胞活力。对于处理后未孵育的细胞，发现除蒽之外的所有三环或更少环的PAHs都没有光细胞毒性，而四环或五环PAHs（除屈外）、苯并[a]蒽、二苯并[a,h]蒽、苯并[ghi]苝、苯并[a]芘、茚并[1,2,3-cd]芘、苯并[b]荧蒽、荧蒽和芘，对人皮肤HaCaT角质形成细胞具有光细胞毒性。如果处理后细胞孵育24小时，与未孵育的细胞相比，PAHs的光细胞毒性作用会大大增强。对于孵育24小时的细胞，除萘之外的所有PAHs都在一定程度上表现出光细胞毒性。暴露于5 microM的四环和五环PAHs（除屈外）以及三环蒽，超过80%的细胞失去活力。PAHs的光细胞毒性与其几种激发态性质密切相关：光吸收、激发单重态能量、激发三重态能量和HOMO-LUMO能隙。所有具有光细胞毒性的PAHs在>300 nm处吸收光，处于太阳UVB和UVA区域。对于具有光细胞毒性的PAH的三个激发态描述符中的每一个都有一个阈值：在密度泛函理论B3LYP/6-31G(d)水平下获得的单重态能量<355 kJ/mol（对应于337 nm光）、三重态能量<230 kJ/mol（对应于520 nm光）、HOMO-LUMO能隙<3.6 eV（对应于344 nm光）。
