NHIK-3025 CELL-CULTURE - A NEW IN-VITRO TEST FOR PHOTOTOXICITY SCREENING

In this study, we used NHIK (Norsk Hydro's Institutt for Kreftforsknin g) 3025 cells, derived from a human carcinoma of the cervix, to screen for phototoxicity. Previously, NHIK 3025 cells have been used in porp hyrin research. A number of sulphonamide-derived oral anti-diabetics a nd diuretics were incubated together with the NHIK cells far one hour and irradiated with broad band UV and WA radiation. Cell death was obs erved in the presence of two oral anti-diabetic drugs and ten diurecti c drugs, and was dependent on WA exposure and the concentration of the test substance. This model proved valuable for the detection of known phototoxic substances, and, in addition, phototoxic properties were d emonstrated far a number of substances not previously shown to exert t hese effects. Electron microscopy of the cells, in the presence of the diuretic bemetizide, showed that biomembranes are the main target for phototoxicity, although nuclear damage was also demonstrated. The add ition of antioxidants reduced the amount of phototoxic cell death, ind icating the participation of reactive oxygen species in the process. T hese procedures shaw that this model can be useful both in screening p rocedures and in mechanistic investigations.