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Photodynamic sensitizers as useful alternative agents have been used for population control against insect pests, and the response of insect ovarian cells towards the photosensitizers is gaining attention because of the next reproduction. In this paper, antioxidative responses of lepidopteran ovarian Tn5B1-4 and Sf-21 cells to photoactivated alpha-terthienyl (PAT) are investigated. PAT shows positive inhibitory cytotoxicity on the two ovarian cells, and its inhibition on cell viability is enhanced as the concentrations are increased and the irradiation time is extended. Median inhibitory concentrations (IC 50 ) are 3.36 μg/ml to Tn5B1-4 cells, and 3.15 μg/ml to Sf-21 cells at 15 min-UV-A irradiation 2 h-dark incubation. Under 10.0 μg/ml PAT exposure, 15 min-UV-A irradiation excites higher ROS production than 5 min-UV-A irradiation does in the ovarian cells, the maximum ROS content is about 7.1 times in Tn5B1-4 cells and 4.3 times in Sf-21 cells, and the maximum malondialdehyde levels in Tn5B1-4 and Sf-21 cells are about 1.47- and 1.36-fold higher than the control groups, respectively. Oxidative stress generated by PAT strongly decreases the activities of POD, SOD and CAT, and induces an accumulation of Tn5B1-4 cells in S phase and Sf-21 cells in G2/M phase in a concentration-dependent fashion. Apoptosis accumulation of Tn5B1-4 cells and the persistent post-irradiation cytotoxicity are further observed, indicating different antioxidative tolerance and arrest pattern of the two ovarian cells towards the cytotoxicity of PAT. [ABSTRACT FROM AUTHOR]

The cytotoxic potential of 13 commonly used agricultural insecticides was examined using cell-based systems with three human HepG2, Hek293, HeLa cells and three insect Tn5B1-4, Sf-21, and Drosophila S2 cells. Data showed that (1) an enhancement of some insecticides (e.g. pyrethroids) on cells proliferation; (2) an inhibition of some insecticides on cells viability; (3) various levels of susceptibility of different cells to the same insecticide; and (4) the cell type dependent sensitivity to different insecticides. The degree of cytotoxicity of insecticides on human cells was significantly lower than that on insect cells ( P <0.05). Methomyl, even 20 μg/ml, showed little cytotoxicity at 24 h exposure whereas emamectin benzoate possessed the strongest cytotoxic potential in a dose-dependent fashion. The results revealed comparable cytotoxic property of agricultural insecticides against intact cells. [ABSTRACT FROM AUTHOR]