[Determination of the irritating potential of environmental substances in an epidermal cell suspension in vitro].

A simple in vitro screening method was established, which allows estimation of the effect of environmental products on cell alteration or irritative potential. Primary cell suspensions, prepared from the epidermis of guinea pig ears through trypsination (0.2%) over night at 4 degrees C, were used. The cell suspension (3 mill./ml) and test substances were mixed in equal portions (500 microliters) and incubated at room temperature for approximately 90 min. The degree of cell alteration was determined by the trypan blue exclusion test. Chemically defined substances as well as disinfectants were employed. The cell alteration was clearly dependent upon substance concentration as well as incubation time. On the basis of the mean alteration time (AT50) measured in vitro, and the mean irritation time (IT50) determined in the patch test in vivo, the substances were ranked according to strength of cell alteration or irritative potency in vitro and in vivo. A good correlation (Spearman's rank correlation, rs = 0.76) was found between the in vitro and in vivo results. Thus, this method is suited for the screening of chemical products especially in industrial laboratories.