本研究对比了生育酚（tocopheryl,VE）、生育酚琥珀酸酯（α-tocopheryl succinate,α-TOS）、生育酚聚乙二醇1000琥珀酸酯（tocopheryl polyethylene glycol 1000 succinate,TPGS）对自由基诱导的蛋白质、脂质、DNA氧化损伤的保护作用,以及对人肝癌细胞（HepG2细胞）增殖抑制作用的差异。结果表明:TPGS对生物大分子氧化损伤的保护作用最明显,α-TOS次之,VE效果最弱。α-TOS、TPGS均能显著降低Hep G2细胞存活率（P＜0.05）,其中TPGS效果更佳,而VE对HepG2细胞增殖无显著影响（P＞0.05）。这可能是由于两亲性的TPGS疏水端吸附在生物大分子表面,亲水端在缓冲液中充分伸展,形成较大的空间位阻,保护生物大分子免受自由基攻击;同时,更好的水溶性使TPGS更易透过生物膜,提高了其在Hep G2细胞内的有效浓度。本研究可为生育酚衍生物应用于健康营养食品提供理论依据。

Objective: The suppressive cytokine interleukin-10(IL-10) plays a central role in allergic and autoimmune diseases.Complement regulatory factor CD46 is a newly found costimulatory molecule for T cell activation, and it can induce IL-10 production in CD4+T cells. The other researches showed CD4+CD25+regulatory T cells(CD4+CD25+Tregs) as an important immuno-suppressive cells can induce surrounding cells secreting IL-10 so as to enlarge the suppressive function. This study was to investigate IL-10 production by CD4+CD25-T cells co-cultured with CD4+CD25+Tregs under CD46 costimulation. Methods: Purified CD4+CD25+Tregs and CD4+CD25-T cells were cultured alone or cocultured at a ratio of 1:10 under stimulation with CD3/CD28 or CD3/CD46, undivided CD4+T cells were also cultured under the same condition for comparison. The levels of IL-10, in supernatants were assessed by enzyme-linked immunosorbent assay(ELISA). Proliferation rates were assayed by(3H-TdR)thymidine incorporation. Results: Levels of IL-10 in the supernatants were higher in cocultured CD4+CD25+Tregs/CD4+CD25-T cells and CD4+T cells than in CD4+CD25-T cells alone, either under CD46 or under CD28 costimulation. Under CD46 costimulation, Levels of IL-10 in CD4+CD25-T cells, cocultured cells and CD4+T cells were higher than under CD28 costimulation, the proliferation rates were lower than CD28. Conclusion: Under CD46 or CD28 stimulation,CD4+CD25+Tregs can induce IL-10 secreting in CD4+CD25-T cells, CD46 as a new co-stimulatory signal can activate higher IL-10 secretion than traditional signal. This study revealed the function of CD4+CD25+Tregs in inducing IL-10 production under CD46 costimulation, thus further researches about activation of immune cells under CD46 pathway are important to identified the relationship of the alterations of immune cells through this new pathway with pathogenesis of some disease.