Photosensitization of Chinese hamster V79 cells to photoactivated alpha-terthienyl involving membrane damage and oxidative stress

Photosensitization of V79 Chinese hamster lung fibroblasts was tested to investigate if the cells can fit the photoactive effect of alpha-terthienyl for safety application. Using 15-min photoirradiation of a black light (320-400 nm, 40 W), alpha-terthienyl was significantly photoactivated and caused V79 cells to be shrinkage, detachment and necrosis. The photoactivated alpha-terthienyl played a concentration-dependent stress to decrease cell survival and to induce cell death with median inhibitory concentration (IC50) as 4.78 μg/ml. Cell viability in MTT assays also fell down to 10.58% of the control in the treatment of 10.0 μg/ml photoactivated alpha-terthienyl. As the irradiation time prolonged and the concentration of photoactivated alpha-terthienyl increased, cell death increased significantly, the intracellular level of reactive oxygen species (ROS) and the content of extracellular malondialdehyde were gradually increased. The changes of peroxidase, superoxide dismutase and catalase activities in V79 cells were positively responsive to the oxidative stress caused by photoactivated alpha-terthienyl. Moreover, using non-photosensitizing condition, the increased cell death and oxidative stress in the treatment of alpha-terthienyl at >7.0 μg/ml were also observed. The results showed the maladjustment response of V79 cells with membrane damage and cell death, clearly demonstrating the photosensitization of animal cells to the photoactivated cytotoxic effect of alpha-terthienyl.