title: Cytotoxicity and negligible genotoxicity of borax and borax ores to cultured mammalian cells.
abstract: The cytotoxicity and genotoxicity of refined borax and borax ores were studied in cultured mammalian cells. In V79 Chinese hamster cells, C3H/10T1/2 mouse embryo fibroblasts, and diploid human foreskin fibroblasts, crude borax ore, kernite ore, and refined borax were all cytotoxic. The lowest concentrations at which cytotoxicity was observed were 0.02 mg/ml and 0.1 mg/ml for borax ore in C3H/10T1/2 and human fibroblasts, respectively, 0.2 mg/ml for kernite ore in both cell types, and 0.1 mg/ml for refined borax in both C3H/10T1/2 and human fibroblasts. The cytotoxicity was dose dependent above these concentrations. The concentrations of borax ore, kernite ore, and refined borax that reduced the relative plating efficiency to 50% were approximately 3.2, 1.6, and 0.8 mg/ml, respectively, in human fibroblasts and were 0.8 mg/ml for all three substances in C3H/10T1/2 cells. All three borax samples were not significantly mutagenic in assays for mutation to ouabain resistance in human fibroblasts an C3H/10T1/2 cells and were at most only weakly mutagenic in an assay for mutation to 8-azaguanine resistance in V79 Chinese hamster cells. Refined borax did not induce neoplastic transformation in C3H/10T1/2 cells. Crude borax ore and kernite ore induced weak transformation that was not dose-dependent and was not reproducible in another experiment. Therefore, borax and its ores are cytotoxic to mammalian cells at high (mg/ml) concentrations and are at most weakly mutagenic but not significantly oncogenic as measured in a cell transformation assay.
mesh_terms: D000818:Animals; D001881:Borates / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced; D002478:Cells, Cultured; D006224:Cricetinae; D004351:Drug Resistance; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D051379:Mice; D009152:Mutagenicity Tests; D010042:Ouabain / Q000494:pharmacology
chemical_list: D001881:Borates; C018851:borax; D010042:Ouabain