Comparison of BALB/c and CBA/J mice for the local lymph node assay using bromodeoxyuridine with flow cytometry (LLNA: BrdU-FCM).
The local lymph node assay using 5-bromo-2-deoxyuridine (BrdU) with flow cytometry (LLNA: BrdU-FCM) is a modified LLNA that is used to identify skin sensitizers by counting BrdU-incorporated lymph node cells (LNCs) with flow cytometry. Unlike other LLNA methods (OECD TG 429, 442A and 442B) in which the CBA/J mouse strain is used, LLNA: BrdU-FCM was originally designed to be compatible with BALB/c, a mouse strain that is more widely used in many countries. To justify the substitution of CBA/J for BALB/c, the equivalence of the test results between two strains shall be established prior to the official implementation of LLNA: BrdU-FCM. This study aims to compare the test results of LLNA: BrdU-FCM produced in BALB/c mice with those in CBA/J mice for 18 reference substances, including 13 sensitizers and 5 non-sensitizers, listed in OECD Test Guideline 429. Based on the LLNA: BrdU-FCM test procedure, we selected an appropriate solvent and then performed preliminary tests to determine the non-irritating dose ranges for the main study, which revealed the difference in the irritation responses to 8 of the 18 chemicals between the two strains. In the main study, we measured the changes in the number of total LNCs, which indicated differences in the responses to test chemicals between the two strains. However, the stimulation index obtained with the counts of BrdU-incorporated LNCs with 7-AAD using flow cytometry yielded comparable results and 100% concordance between the BALB/c and CBA/J mouse strains was achieved, suggesting that the performance of LLNA: BrdU-FCM using BALB/c mice was equivalent to that with CBA/J mice.
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea.
Yong Sun
YS
Lee
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea.
Jung-Sun
JS
Yi
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea.
Souk Jin
SJ
Seo
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea.
Joo Hwan
JH
Kim
Pharmacology Efficacy Team, Biotoxtech Co., Ltd., Ochang-eup, Cheongju-si, Republic of Korea.
Mi-Sook
MS
Jung
Pharmacology Efficacy Team, Biotoxtech Co., Ltd., Ochang-eup, Cheongju-si, Republic of Korea.
Im-Kwon
IK
Seo
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea.
Ilyoung
I
Ahn
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea.
Kyungyuk
K
Ko
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea.
Tae Sung
TS
Kim
College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea.
Kyung Min
KM
Lim
Toxicological Screening & Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si, Republic of Korea. Electronic address: sjsohn@korea.kr.
Soojung
S
Sohn
D000279:Administration, Cutaneous; D000818:Animals; D001973:Bromodeoxyuridine; D049109:Cell Proliferation / Q000187:drug effects*; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D007509:Irritants / Q000008:administration & dosage / Q000633:toxicity*; D023441:Local Lymph Node Assay; D008198:Lymph Nodes / Q000187:drug effects* / Q000473:pathology; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D015203:Reproducibility of Results; D013045:Species Specificity; D013997:Time Factors
D007509:Irritants; D001973:Bromodeoxyuridine
BALB/c; BrdU-FCM; CBA/J; Flow cytometry; LLNA; Local lymph node assay; Skin sensitization