Development of an in vitro model to study oxidative DNA damage in human coronary smooth muscle cells

Oxidative damage in the vascular system has been linked to the development of atherosclerosis. The aim of the present study was to establish a cell culture model for the investigation of in vitro induced oxidative DNA injury, its modulation and repair kinetics. Primary cultures of human coronary artery smooth muscle cells were used as target cells. The cells were exposed to hydrogen peroxide (H2O2). DNA damage was quantified by the alkaline single-cell gel electrophoresis assay (comet assay). This method allows quantification of DNA single and double strand breaks and of alkali-labile sites in individual cells. In the present study H2O2 concentration-responses and dependence of damage on exposure time and temperature were evaluated and the repair kinetics were studied. The results show that this cell culture model can be employed to study oxidative DNA injury in the cells of the human cardiovascular system, a promoter of cardiovascular disease. Further it offers the possibility to investigate pharmacological modulators of such oxidative effects. Such modulators are antioxidants like vitamin C and E, steroid hormones, phytoestrogens, or synthetic agents. Today, pigs, rabbits or rats are used to test systemic and local administration of the named modulating substances, the latter by use of special catheters or stents placed inside the arteries. These experiments require treatment observation over a number of weeks and killing of the animals at the end of the experiment. By using the proposed cell culture model such animal experiments could be partly avoided.