The Chromium-51 Release Cytotoxicity Test: Comparison to the Agar Overlay and Cell-Growth Inhibition Tests

Abstract

The 51Cr-release assay was compared to the agar overlay and cell-growth inhibition assays for cytotoxicity. L-929 mouse fibroblasts were used in each of the three assays. Incubation of Na 51CrO4 labeled cells with increasing concentrations of phenol caused a dose-related accumulation of 51Cr in the medium. The effective dose for a 50% response ED50 was 1.1% phenol. Increasing concentrations of phenol caused a dose-related increase in cell damage as determined in the agar overlay assay (ED50 = 0.75% phenol) and a dose-dependent inhibition of cell growth (ED50 = 0.45% phenol). The sensitivity of the cell-culture methods compared favorably with the in vivo intracutaneous reactivity test in rabbits. These studies demonstrate that the 51Cr-release assay is of similar sensitivity to commonly used cell-culture cytotoxicity tests. The cell-culture tests offer better convenience and are faster and less costly than in vivo methods currently in use.