Alternative to primary Draize skin irritation test using cultured human skin model: Comparison of six endpoints

Katsuyasu Morota1, Noriyuki Morikawa1, Shin-Ichiro Morita1 Hajime Kojima2, and Hiroaki Konishi2
1Kyoto Research Laboratory, GUNZE Ltd., 1 Ishiburo, Inokura-shinmachi, Ayabe*city, Kyoto 623-0051, Japan
2Research Institute, Nippon Menard Cosmetic Co., Ltd., 2-7 Torimicho, Nishi-ku, Nagoya 451-0071, Japan

Correspondence: Katusyasu Morota, Kyoto Research Laboratory, GUNZE Ltd., 1 Ishiburo, Inokura-shinmachi, Ayabe-city, Kyoto 623-0051, Japan
Phone:+81-773-42-0141 Fax:+81-773-43-0362

Running title: Alternative to Draize skin irritation test

Original paper :AATEX 6(1):41-51,1999
In this study, we evaluated skin irritancy of test chemicals by using six endpoints. As an endpoint, the cell viability was evaluated with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and neutral red (NR). In addition, lactate dehydrogenase (LDH), interleukin-1a (IL-1(alpha)), interleukin-8 (IL-8), and prostaglandin E2 (PGE2) releases from the cells were measured. Each assay was compared with in vivo animal testing and with one another. The results indicated the assays could be divided into 3 groups, MTT/NR, LDH/IL-1(alpha), and IL-8/PGE2. The MTT and NR assays revealed good correlation with in vivo scores, except for croton oil; the IL-8 and PGE2 assays could detect the irritancy of croton oil. On the whole, the LDH, IL-1(alpha), IL-8, and PGE2 assays had poor correlation with in vivo scores.
Furthermore, time transition of skin irritancy was examined by the MTT, IL-8, and PGE2 assays. Production of IL-8 and PGE2 was related to cell viability as determined by the MTT assay.
This model may be reliable for predicting skin irritancy of chemicals and for studying mechanisms of irritancy by using a combination of endpoints

Key words:skin model, skin irritancy, MTT, NR, LDH, IL-1(alfa), IL-8, PGE2