Cell transformation and promoter activity of insulation oils in the Syrian Hamster Embryo cell and in the C3H/10T1/2 mouse embryo fibroblast test systems

Abstract

The ability of mineral‐oil‐based and synthetic cable insulating fluids to transform and promote transformation of mammalian cells in vitro have been studied. In experiments with the Syrian hamster embryo cell transformation assay, it was found that C ₁₅ ‐C ₁₈ alkylbenzenes were the most potent inducers of transformation, followed by low‐viscosity and residual mineral oils. No activity and low cytotoxicity were found for a low‐viscosity polyisobutylene‐based oil. In the two‐stage transformation assay of C3H/10T1/2 cells, promoter activity was obtained with all fluids tested. A blend of residual and low‐viscosity mineral oils showed the highest activity. This oil possessed a low cytotoxicity and was tested at a relatively high concentration. The alkylbenzenes were more potent than the polyisobutylene‐based fluid. The alkylbenzenes were also found to possess initiating activity in the two‐stage assay, when 12‐O‐tetra‐decanoylphorbol 13‐acetate (TPA) was used as promoter. All the fluids showed low potency compared to benzo[a]pyrene and the tumor promoter TPA.