Acute dermal toxicity: in vivo and in vitro comparisons in mice

Mouse skin was exposed topically to solutions of dinitrochlorobenzene (DNCB), croton oil (CO), epoxyethylbenzene (EEB), ethanolamine (EtNH2), or isopropylmyristate (IPM), and the histologic response evaluated 20 hr later with light microscopy. In a parallel series of experiments, discs of mouse skin were collected, exposed in vitro to the same chemicals and examined histologically after 20 hr in culture. Additionally, cellular enzyme leakage was determined in the culture medium. DNCB was the most toxic to the skin followed by CO and EEB. IPM and EtNH2 were toxic only at the highest concentration used (10%). There were good correlations between the magnitude of the skin lesions and the levels of enzyme activity in the culture medium. The results show that morphologic responses of skin maintained in organ culture are an indicator of in vitro skin toxicity. Moreover, enzyme leakage may provide a means for detecting sublethal cell injury which might not be observed histologically.