Disposition and biotransformation of 14C-Benzo(a)pyrene in a pig ear skin model: ex vivo and in vitro approaches.
Biotransformation of chemicals by the skin is a critical determinant of systemic exposure in humans following dermal absorption. Pig ear skin potentially represents a valuable alternative model since it closely resembles to human skin. We developed an ex vivo pig ear skin system which absorption, diffusion and metabolic capabilities were investigated using benzo(a)pyrene [B(a)P] as a model molecule. The potential of the ex vivo pig ear skin model to biotransform xenobiotics was compared with metabolic data obtained using dermal and hepatic microsomes from human and pig. (14)C-B(a)P [50-800 nmol] was applied on the surface of skin models. The diffusion and the production of B(a)P metabolites were quantified by radio-HPLC, LC-MS/MS and NMR. B(a)P was extensively metabolized by pig ear skin explants, the major metabolites being B(a)P-glucuronide and sulfate conjugates. B(a)P-OHs, B(a)P-diols, B(a)P-catechols and B(a)P-diones were also identified. In the pig ear skin model developed, skin diffusion was maintained over 72 h and both phase I and phase II activities were expressed, with the formation of similar metabolites as produced in incubations with liver and skin microsomal fractions. This ex vivo model, which combines a functional skin barrier and active biotransformation capabilities, appears to represent a valuable alternative tool in transdermal exposure studies.
Jacques
Carine
C
INRA, UMR 1089 Xénobiotiques, 180 Chemin de Tournefeuille, BP 93173, 31027 Toulouse Cedex 3, France.
Perdu
Elisabeth
E
Duplan
Hélène
H
Jamin
Emilien L
EL
Canlet
Cécile
C
Debrauwer
Laurent
L
Cravedi
Jean Pierre
JP
Mavon
Alain
A
Zalko
Daniel
D
D000279:Administration, Cutaneous; D000818:Animals; D001564:Benzo(a)pyrene / Q000493:pharmacokinetics*; D001711:Biotransformation; D002250:Carbon Radioisotopes; D002273:Carcinogens / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D004431:Ear, External; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D012867:Skin / Q000187:drug effects* / Q000378:metabolism; D012869:Skin Absorption / Q000187:drug effects / Q000502:physiology; D021241:Spectrometry, Mass, Electrospray Ionization; D013552:Swine; D053719:Tandem Mass Spectrometry
D002250:Carbon Radioisotopes; D002273:Carcinogens; D001564:Benzo(a)pyrene