ASSESSMENT OF ANTIMUTAGENIC EFFECTS OF STOBADINE DIHYDROCHLORIDE ON MNNG-INDUCED MUTATIONS IN CHINESE-HAMSTER CELLS V79

Mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and antimu tagenic effect of antioxidant stobadine (STB) were investigated by so called HGPRT/V79 system, Cells were treated by STB before, during and after MNNG-treatment. Our results showed that the highest antimutageni c effect of STB was observed if the drug was given as a pretreatment b efore exposure of cells to MNNG. This effect was not concentration-dep endent within the framework of 1.5-9 mmol. Ail other combinations of M NNG- and STB-treatment led to the weaker but statistically significant decrease of 6-TG(r) mutations. Inhibition of proteosynthesis induced by methylxanthine pentoxifylline in the time of pre-MNNG-treatment rem oved completely antimutagenic effects of STB. In addition to mutagenic ity assays, cytotoxicity of STB and combined effects of MNNG and STB w ere studied. Trypan blue exclusion and growth activity of influenced c ells showed that the application of STB (1.5 mmol) before or after MNN G (0.5 mu g/ml) treatment had a similar toxic effect as MNNG alone. Ap plication of STB during MNNG-treatment or pretreatment of cells with S TB followed by combined treatment of cells by STB + MNNG statistically significantly decreased viability of cells. There are probably no rel ationships between the antimutagenic and the toxic effects of combined influence of STB and MNNG on V79 cells.