Local lymph node assay with non-radioisotope alternative endpoints.
The local lymph node assay has recently been accepted by regulatory agencies as a stand-alone alternate method for predicting allergic contact dermatitis. To compare the sensitivity of non-radioisotope methods with that of the standard assay, we determined if these modified methods would affect evaluation of sensitization potency. For this reason, we used 2,4-dinitrochlorobenzene (DNCB) and benzocaine for different sensitizing criteria. Female CBA mice were treated for 3 days with a test compound or vehicle applied to each side of both ears. Bilateral auricular lymph node proliferative activity was assessed by the following endpoints with incorporation of 3H-methyl thymidine (3H-TdR), bromodeoxyuridine (BrdU) in vivo, and BrdU ex vivo, IL-2 production, and proliferating cell nuclear antigen (PCNA) expression. Ear thickness was also tested. The strong sensitizer DNCB was detectable by any of the non-radioisotope endpoints as well as by radioisotope-dependent standard assay. On the other hand, when evaluating the weak sensitizer benzocaine, significant changes were evident in BrdU incorporation ex vivo and in vivo, and IL-2 production. We believe that these non-radioisotope methods can assess allergic contact dermatitis caused by chemicals even in the laboratory, where it can be difficult to handle radioisotopes.
Suda
Akiko
A
Toxicology Laboratory, Drug Metabolism and Toxicology Research Center, Taisho Pharmaceutical Co., Ltd., 1-403, Yoshino-cho, Saitama-shi, Saitama 330-8530, Japan.
Yamashita
Masahiro
M
Tabei
Mitsuyuki
M
Taguchi
Kazuhiko
K
Vohr
Hans-Werner
HW
Tsutsui
Naohisa
N
Suzuki
Ritsuyoshi
R
Kikuchi
Katsuaki
K
Sakaguchi
Keisuke
K
Mochizuki
Kouki
K
Nakamura
Kazuichi
K
D000485:Allergens / Q000633:toxicity; D000818:Animals; D001566:Benzocaine / Q000633:toxicity; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis*; D004137:Dinitrochlorobenzene / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004431:Ear, External / Q000187:drug effects; D023381:Endpoint Determination / Q000379:methods*; D005260:Female; D005434:Flow Cytometry; D023441:Local Lymph Node Assay; D008198:Lymph Nodes / Q000378:metabolism; D051379:Mice; D008808:Mice, Inbred CBA; D011868:Radioisotopes / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000485:Allergens; D004137:Dinitrochlorobenzene; D011868:Radioisotopes; D001973:Bromodeoxyuridine; D001566:Benzocaine