Evaluation of Skin Irritation in a Reconstituted Human Dermal Model (3-D Model) Using Water Insoluble Fatty Acids, Fatty Alcohols and Hydrocarbons

Hajime Kojima, Atsushi Sato, Asao Hanamura, Tomonori Katada and Hirokaki Konishi

Research Institute, Nippon Menard Cosmetic Co., Ltd., 2-7 Torimi-cho, Nishi-ku, Nagoya 451-0071 Japan

Original Article AATEX 5(4):201-210,1998
With the aim of improved prediction of human skin irritation, cytotoxicity tests were conducted using a reconstituted human dermal model (Skin2TM cultured 3-Dimensional Skin Model, ZK1300: 3-D model). A range of water-insoluble substances, namely fatty acids, fatty alcohols and hydrocarbons, were tested with MTT(3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyl tetrazolium bromide) reduction, LDH (lactate dehydrogenase) release and prostaglandin E2(PGE2) release using as cytotoxicity markers. Results for these parameters were compared with those obtained from a cytotoxicity test (MTT reduction assay) using cultured monolayers of human dermal fibroblasts (NB1RGB), from a rabbit primary skin irritation test and from human patch testing.
The MTT reduction assay with the 3-D model proved able to predict human primary and cumulative skin irritation of the test substances, though the match to fibroblasts results and rabbit primary skin irritation score was not perfect. Our finding also showed little variation with the different cytotoxicity markers applied in the 3-D model for the present insoluble test substances.
We therefore consider that the MTT reduction assay in the 3-D model is a reliable method to evaluate the human skin irritation potential of new chemicals.

Key words: skin irritation, reconstituted human dermal model, in vitro, fibroblasts, fatty acid, fatty alcohol, hydrocarbon.