番茄汁对DNA损伤的保护作用研究

Study on the Protective Effect of Tomato Juice on DNA Damage in Cells

目的探讨番茄汁对人正常细胞和肿瘤细胞增殖的影响及DNA损伤的保护作用。方法采用MTT法检测不同剂量的番茄汁对细胞增殖的影响，彗星实验检测不同剂量番茄汁对细胞DNA的影响及对DNA损伤的保护作用。结果当番茄汁体积在培养液中所占比例低于15％时。对正常细胞和肿瘤细胞的增殖没有任何影响；当番茄汁在培养液中所占比例达到或超过20％时。此时的培养液不是细胞生长的最适条件，表现为细胞生长抑制。番茄汁在培养液中体积分数为50-500μL／mL时没有引起细胞DNA损伤，而低浓度（20～100μL／mL）番茄汁对重铬酸钾诱导的DNA损伤具有明显的保护作用，该作用随着番茄汁剂量的增加而增强。表现为拖尾细胞减少,尾长减短，番茄汁剂量与拖尾细胞尾长具有明显的剂量-反应关系。呈负相关（r=-0．917，P=0．00369）。肿瘤细胞和正常细胞实验结果一致。结论番茄汁不但不会引起细胞DNA损伤。而且对重铬酸钾诱导的DNA损伤具有明显的保护作用；此外，在研究番茄汁对细胞增殖影响时应该注意番茄汁在培养液中所占的体积，本实验显示番茄汁不能超过20％，否则会得到错误的结论。

Objective To test the effect of tomato juice on the growth of human normal cells （HLF line） and tumor cells （A549 cells line） and its protective effects on DNA damages for both cells. Methods The effect of tomato juice on the proliferation of cells was measured by MTT assay. The comet assay was undertaken to detect the protective effect of tomato juice on DNA damages of cells induced by potassium dichromate （K2Cr2O7）. Results No effect of tomato juice on the growth of human normal cells and tumor cells when the proportion of tomato juice in cell culture fluid under 15% ; cell growth was inhabited when the proportion of tomato juice in cell culture fluid was up to or higher than 20%. No DNA damages were identified when tomato juice was set at a concentration between 50 to 500 μL/mL. Protective effects of tomato juice at 20-100 μL/mL on DNA damages were found, showing decreased. Percentage of tailed cells and length of tails for both normal and tumor cells. A negative dose-response relationship between the concentration of tomato juice and tail length was revealed （r=-0. 917, P：0. 00369）. Conclusion Tomato juice can＇t damage the DNA of cells, but reduce the DNA damage induced by potassium dichromate （KzCr2O7） in both human normal and tumor cells. Furthermore, to test the effect of tomato juice on the growth of cells, we must consider the volume proportion of tomato juice in cell culture fluid, just as the result shown in our study, if the proportion of tomato juice exceed 20%, the conclusion may be unbelievable.