Adrenaline is a neurotransmitter and hormone that plays an important role in physiological regulatory mechanisms. The objective of this study was to assess primary DNA damage in isolated human lymphocytes exposed to adrenaline using the in vitro comet assay. Dose-response of human lymphocytes was determined at concentration range of adrenaline from 0.01 μM to 300 μM for various treatment times (1h, 2h, 4h and 24h). The obtained results showed that adrenaline induced DNA damage at concentration range from 5 μM to 300 μM after 1h, 2h and 4h of treatment. The slightest DNA damage was observed after 24 h of adrenaline treatment -only the highest concentrations of adrenaline (150 μM and 300 μM) caused increased level of DNA damage. In order to evaluate the potential contribution of reactive oxygen species (ROS) in adrenaline-induced DNA damage we used antioxidants catalase (100 IU/mL and 500 IU/mL) and quercetin (100 μM and 500 μM). Co-treatment of lymphocytes with adrenaline (300 μM) and antioxidants for 1 h, signifi cantly reduced the quantity of DNA in the comet tails. Therefore, it can be concluded that adrenaline exhibits genotoxic effects mainly through induction of reactive oxygen species and that some of the DNA damage is repaired during the fi rst four hours following the treatment with adrenaline.

Objective. Inosine 5'-monophosphate dehydrogenase (IMPDH) activity in cancer cells is increased. Tiazofurin selectively inhibits the activity of IMPDH, and it has been granted for the treatment of different cancers and new viral diseases. Its widespread use was limited because exposure to tiazofurin under certain circumstances was found to have a higher frequency of severe non-hematologic toxicity. Therefore, the objective of this study was to examine genotoxic action and inducement of DNA damage of tiazofurin using the comet assay. Methods. The ability of tiazofurin to induce DNA damage was evaluated using single-cell gel electrophoresis (SCGE) technique/comet assay. Human whole blood cells were exposed to three final concentrations of tiazofurin (1µM/mL, 2 µM/mL, and 5 µM/mL) for 30 min in vitro. Results. Our results indicate that tiazofurin produced a significant level of DNA damage on whole blood cells after 30 min of exposure vs. control. All tested concentrations were significantly comet-forming, in a concentration-dependent manner. Conclusion. Our investigation on the tiazofurin-treated cells and their relationship to the formation of DNA damage demonstrated that the genotoxic effect was induced after exposure to tiazofurin under described conditions.