An investigation of detergent action on cells in vitro and possible correlations with in vivo data

Synopsis A cell fluorescence method for quantifying the effects of detergents on cultured cell lines is described. The results are discussed in relation to other findings in the literature. These results are compared to data obtained with the same detergents in the rabbit eye test and the possible correlations and discrepancies are considered. Summary Details are given of the culture of two human epithelioid cell lines (HeLa and HEp2) and their utilization in a procedure to assess the cytotoxicity of detergents on cells in monolayer culture. The method is dependent on the ability of relatively intact cells to liberate and retain fluorescein from fluorescein diacetate. Ethidium bromide, a red fluorescent compound, is used to stain the nuclear material remaining in membrane-damaged cells. The results of the in vitro test are compared to the data obtained from the responses seen in the rabbit eye on instillation of the same detergents. For sodium and triethanolamine alkyl sulphates at comparable concentrations, an increase in chain length increases the in vitro cytotoxicity but decreases the effects seen in the conjunctivae, cornea and iris. For the C12, C14 and C16 alkyl trimethylammonium bromides, an increase in chain length increases in vitro cytotoxicity as well as the in vivo responses. Tweens 20 and 40 appeared more damaging in vivo than Tweens 60 and 80; this differentiation was not observed in vivo. The findings of both tests are discussed in terms of detergent solubilities, penetration of, and adsorption of tissues in vivo as well as the effects of detergents on enzymes.