| 17141480 |
Kurita M, Shimauchi T, Kobayashi M, Atarashi K, Mori K, Tokura Y: Induction of keratinocyte apoptosis by photosensitizing chemicals plus UVA. J Dermatol Sci. 2007 Feb;45(2):105-12. Epub 2006 Dec 1.
BACKGROUND: The capacity of photosensitizing chemicals with ultraviolet A light (UVA) to induce apoptosis is one of the methods to assess their phototoxic and potentially photoallergic properties, since apoptotic cells may be easily presented by antigen-presenting cells. OBJECTIVES: We examined the photoaggravated ability to induce keratinocyte apoptosis of various chemicals that are known as causative agents of photocontact dermatitis and drug photosensitivity involving photoallergic and/or phototoxic mechanisms. METHODS: HaCaT keratinocytes were incubated with 3,3',4',5-tetrachlorosalicylanilide (TCSA), bithionol, diphenylhydramine, chlorpromazine, 6-methylcoumarin, sparfloxacin, and enoxacin at 10 (-7) to 10 (-4) M and irradiated with UVA at 4J/cm (2). As positive control, 8-methoxypsoralen (8-MOP) was also tested. Apoptosis and necrosis were evaluated by flow cytometric enumeration of annexin V (+) 7-AAD (-) and annexin V (+) 7-AAD (+) cells, respectively. The expression of apoptosis-related molecules, caspase-3 and poly (ADP-ribose) polymerase (PARP), was tested by flow cytometric and Western blotting analyses. RESULTS: In a comparison with non-irradiated cells, significant apoptosis was found in TCSA, bithionol, chlorpromazine, sparfloxacin and enoxacin at 10 (-4) or 10 (-5) M as well as 8-MOP as assessed by both annexin V and active caspase-3 stainings, while necrosis occurred in most of these chemicals at 10 (-4) M. Neither apoptosis nor necrosis was seen in diphenylhydramine or 6-methylcoumarin. PARP were activated in HaCaT cells phototreated with TCSA, bithionol and chlorpromazine. CONCLUSIONS: We suggest that our method is useful for in vitro assessment of phototoxicity and potential photoallergenicity of chemicals. |
82(1,1,1,2) |