吸烟烟气的细胞毒性作用和茶多酚保护作用的研究

以体外培养的中国仓鼠肺成纤维细胞V79为模型，用分光光度法和ESR自旋标记方法研究了吸烟烟气对细胞的损伤以及抗氧化剂茶多酚（GTP）的保护作用。结果表明，吸烟烟气能引发V79细胞膜的脂质过氧化，导致细胞死亡，使膜浅层的流动性增加，但对膜深层的动态性质没有明显改变。加入GTP后能抑制烟气引起的膜脂过氧化和膜流动性的改变以及细胞死亡，且这种抑制作用与GTP的浓度呈量效关系，而GTP本身对细胞膜浅层的流动性无明显作用，但对深层的流动性则有一定的影响。此外，还用马来酰亚胺自旋探针研究吸烟烟气对细胞膜膜蛋白巯基结合位点局部构象的影响，结果发现，随着烟气作用增强，ESR波谱的强弱固定化比值（S/W）增大，表明膜蛋白上巯基结合位点处结构变得紧密，这说明吸烟烟气改变了膜蛋白的构象，GTP本身在高浓度（＞0.1mg/mL）时也能使S/W增大，当低浓度（＜0.05mg/mL）则没有影响。当GTP浓度为0.01mg/mL时就可以抑制烟气引起的S/W的增大。

Cytotoxicity of gas phase cigarette smoke and the protection by green tea polyphenols

To assess the toxicological effect of gas phase cigarette smoke (GPCS) on cells and their protection by green tea polyphenols(GTP), a mouse fibroblast cell line, Chinese hamster lung V79 cell, was used. Exposure of the cultured V79 cells to GPCS decreased cell viability and caused lipid peroxidation of cell membrane as measured by thiobarbituric acid reaction. ESR spin labeling studies indicated that GPCS exposure could increase the fluidity in the polar surface of cell membrane, but the membrane fluidity in the hydrophobic region was not affected. The conformation of sulfhydryl binding sites on membrane was changed. Incubation ofV79 cells with GTP aqueous solution before GPCS treatment could decrease cell death and lipid peroxidation and inhibit the changes of the biophysical properties of cell membrane induced by GPCS in a dose-dependent manner. GTP itself(0. 1mg/mL) had no effect on the polar surface of membrane, but could increase the fluidity in the hydrophobic region and change the conformation of sulfhydryl binding sites on membrane proteins. These findings indicate that GPCS can induce lipid peroxidation and affect the biophysical properties of cell membrane ,which may account for the toxicity of GPCS, and that GTP can prevent these changes possibly by inhibiting the membrane lipid peroxidation.