Modification of the action of misonidazole. I. Effect of TAN on toxicity

The toxicity of misonidazole, an electron affinic radiosensitizer, is greatly reduced by TAN, a free radical radiosensitizer. The production of single-strand breaks in DNA of mammalian cells incubated in dilute suspension with misonidazole (15 mM) under hypoxic conditions is greatly decreased by the presence of TAN (10 mM). The survival of such cells is also greatly enhanced if TAN is present at a concentration of 10mM even less. The implications and possible mechanisms of this finding are discussed.