Michael Brand, Presenter: Nothing to Disclose

Sabine Vogt, Abstract Co-Author: Nothing to Disclose

Christina Engert, Abstract Co-Author: Nothing to Disclose

Michael Uder MD, Abstract Co-Author: Speakers Bureau, Bracco Group Speakers Bureau, Siemens AG Research Grant, Siemens AG

Michael Andreas Kuefner, Abstract Co-Author: Nothing to Disclose

Aim of this study was to evaluate the effect of different antioxidants like N-acetylcysteine (NAC), Vitamin C, Selenium, and β-Carotene on the formation of radiation induced DNA double-strand breaks (DSBs).

For in-vitro experiments blood samples were obtained from 40 healthy volunteers. Samples were irradiated with 10 mGy both without treatment as well as after pre-incubation with NAC (final concentration 50 mg/l), Vitamin C (100 mg/l), Selenium (20 µg/l) or β-Carotene (1 mg/l). Non-irradiated samples served as controls. Blood lymphocytes were isolated, stained against the phosphorylated histone variant γ-H2AX using a specific antibody and DSBs were quantified using fluorescence microscopy. Numbers of x-ray induced DSBs were calculated by subtracting pre-exposure from corresponding post-exposure levels.

Baseline levels ranged from 0.089-0.123 DSBs/cell (median 0.100/cell). In non-treated samples the median x-ray induced DSB level was 0.121/cell (range 0.115-0.129/cell) 5 minutes after irradiation. At the same radiation dose in samples pre-treated with NAC median of DSBs was 0.058/cell (range 0.010-0.076/cell, p=0.04). Pre-incubation with Vitamin C (median 0.133/cell; range 0.125-0.146/cell; p>0.05), Selenium (median 0.142/cell; range 0.125-0.153/cell; p>0.05) and β-Carotene (median 0.143/cell; range 0.124-0.189/cell, p>0.05) did not lead to a significant reduction of x-ray induced DSB-levels. Addition of NAC after irradiation did not result in lower DSB levels indicating that the effect is caused by reduced DSB induction and not by accelerated DSB repair.

In the tested concentration the antioxidant NAC leads to a 50% reduction of radiation induced DNA-DSBs. There is no effect of Vitamin C, Selenium and β-Carotene on DSB induction. Whether an application of NAC before radiologic examinations is useful for radiation protection should be subject of future patient studies.

The antioxidant NAC protects cells from x-ray induced DNA damages.

Brand, M, Vogt, S, Engert, C, Uder, M, Kuefner, M, Effect of Antioxidants on Radiation-induced DNA Double-Strand Breaks.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043879.html