Effects of UVA and visible light on the photogenotoxicity of benzo[a]pyrene and pyrene

Abstract

This study investigated the role of UVA/visible light (U, 320-800 nm) and visible light (V, 400-800 nm) in the phototoxicity and photogenotoxicity of two ubiquitous polycyclic aromatic hydrocarbons (PAH): benzo[a]pyrene (BaP) and Pyrene (Pyr). These mechanisms were evaluated by the WST-1 test and the comet assay on normal human keratinocytes (NHK) and by the micronucleus test on CHO cells. The production of reactive oxygen species (ROS) was assessed through the induction of 8-oxodeoxyguanine (8-oxodG) lesions by immunofluorescence staining in NHK. Results of the WST-1 test revealed the phototoxic properties of BaP and Pyr after irradiation with U and V lights. BaP presented the highest phototoxic properties. Results of the comet assay showed that U- and V-irradiated BaP and Pyr induced increasing rates of DNA single-strand breaks in NHK, in a dose dependent manner. The tested PAH could also induce increased levels of micronuclei in CHO cells after U and V irradiations. Increasing 8-oxodG levels were detected after U and V irradiations in BaP- and Pyr-treated keratinocytes and confirmed the involvement of ROS in the photogenotoxicity of PAH. Overall, this study highlighted the existence of an alternative pathway of PAH genotoxicity that is induced by UVA and/or visible light. Visible light is suggested to photoactivate PAH by a mechanism which is mainly based on oxidative reactions.

Phototoxicity and Environmental Transformation of Polycyclic Aromatic Hydrocarbons (PAHs)—Light-Induced Reactive Oxygen Species, Lipid Peroxidation, and DNA Damage

“…There are numerous reports that photooxidation of PAHs in the environment produces oxygenated PAHs and PAH quinones [55,[74][75][76][77][78][79][80]. A number of reviews have reported photooxidation and photodegradation of PAHs in the environment [81][82][83][84].…”

Genotoxic and mutagenic effects of lipid-coated CdSe/ZnS quantum dots

“…The UVB are highly mutagenic for the tester strains. The irradiation dose was 45 kJ/m 2 , which has been shown to be without genotoxic activity [17]. During the irradiation experiments the temperature of the samples was kept at 4 • C with a regulated cooling system.…”

A study of the phototoxic effect of Benzo[a] Pyrene on bacteria

“…The results of Tobit et al [39] showed that the 1 O 2 generation by BaP produced phototoxicity under the exposure of UVA, UVB and sunlight (mentioned above). Botta et al [41] investigated the effect of UVA/visible light role (320-800 nm) and visible light role (400-800 nm) on the phototoxicity and photogenotoxicity of BaP. Results revealed the phototoxic properties of BaP after irradiation with both light sources.…”

“…Results revealed the phototoxic properties of BaP after irradiation with both light sources. BaP as one of the major carcinogens PAHs has a relatively high phototoxicity [41].…”