Abstract
Synopsis: We have successfully demonstrated that cells in culture are sensitive to damage produced by a variety of phototoxic agents. Differences in the apparent sensitivity of the three cell systems employed (photohaemolysis, phototoxicity to macrophages and to Chinese hamster CHV79 cells) have been exploited to reflect the mechanism of action of the phototoxic materials. Overall four distinct patterns of phototoxic response were observed which indicate specific sites of action of the phototoxic materials within the cell. Of the two halogenated antiseptics tested 3,3′,4′,5‐tetrachlorosalicylanilide (T4CS) was phototoxic and 3,4,4′‐trichlorocarbanilide (TCC) was not; of the drugs both 8‐methoxypsoralen (8‐MOP) and chlorpromazine (CP) were phototoxic; and of the three dyes rose bengal (RB) and Blankophor (FB) were phototoxic and Tinapol (EMS) was not. Phototoxic cellular damage produced by CP, RB and FB could be totally prevented by continuous gassing with O2‐free, 5% CO2 in N2. T4CS and 8‐MOP phototoxic cellular damage was found to proceed independently of the presence or absence of O2.