Cytotoxicity evaluation of the whole protein extract from Bar-transgenic rice on Mus musculus lymphocytes.
With the expanding demand for genetically modified (GM) rice, its safety evaluation is of great significance. Therefore, this study was carried out to assess the acute cytotoxicity of the whole protein extract from GM rice Bar68-1 in Mus musculus lymphocytes in vitro. Cell viability was determined by Cell Counting Kit-8 (CCK-8) and Neutral Red Uptake (NRU) tests. CCK-8 tests was carried out according to the manufacturer's instructions. Cell dehydrogenase (catalytic redox enzymes) activity was spectrophotometrically determined at 450 nm. The tests result were recorded immediately. NRU tests were completed under yellow light in a dark room according to an improved protocol. Lysosomal uptake of neutral red was spectrophotometrically determined at 540 nm and the results were recorded immediately. The results showed that the survival rate of M. musculus lymphocytes in the positive control group was significantly less than in the blank control group (P < 0.05). Moreover, an exposure- time-effect relationship was observed in the positive control group with CCK-8 and NRU tests. There was no significant difference in survival rate between GM rice Bar68-1group and non-GM rice D68 group (P > 0.05). The GM rice Bar68-1 group also did not show a higher survival rate than non-GM rice D68 group (P > 0.05). These results suggested that the whole protein extract from Bar68-1 and D68 were equivalent in their cytotoxicity, and GM rice Bar68-1 had no acute cytotoxic effect on M. musculus lymphocytes in vitro.