Brisson Lydie, Castan Stéphane, Fontbonne Hervé, Nicoletti Cendrine, Puigserver Antoine, Ajandouz El Hassan
BiosCiences FRE CNRS 3005-Université Paul Cézanne-Aix Marseille III, Case 342, Faculté des Sciences et Techniques de Saint Jérôme, 13397 Marseille, France.
Chem Phys Lipids. 2008 Jul;154(1):33-7. doi: 10.1016/j.chemphyslip.2008.04.002. Epub 2008 Apr 26.
Caco-2 cells were used as a model for investigating and comparing the absorption of alpha-tocopherol (Tol) and alpha-tocopheryl acetate (Tac) solubilized in micelles based on a mixture of sodium taurocholate (NaTC) and oleic acid. Surprisingly, the uptake of Tac was found to be similar to that of Tol, and in both cases, the dose-response plots suggest that protein-mediated transport processes were involved. Moreover Tol or Tac were also secreted into the basolateral medium of Caco-2 cells but Tac was mainly hydrolyzed either prior to absorption or intracellularly. The solubilization of Tol or Tac by NaTC on the apical side of the cell monolayer is a prerequisite for the uptake process, although larger amounts of the bile salt are necessary to solubilize Tac than Tol. Caco-2 cells showed hydrolytic activity on Tac, and additional cholesterol esterase may be taken up by the cells, thus increasing the rates of intracellular hydrolysis of Tac. Based on our findings, a scheme is suggested accounting for the absorption of alpha-tocopheryl acetate by enterocytes.
以牛磺胆酸钠（NaTC）和油酸混合物为基础制备的胶束中增溶的α-生育酚（Tol）和α-生育酚乙酸酯（Tac），采用Caco-2细胞作为模型来研究和比较它们的吸收情况。令人惊讶的是，发现Tac的摄取与Tol相似，并且在两种情况下，剂量反应曲线表明涉及蛋白质介导的转运过程。此外，Tol或Tac也分泌到Caco-2细胞的基底外侧培养基中，但Tac主要在吸收前或细胞内被水解。细胞单层顶端侧NaTC对Tol或Tac的增溶作用是摄取过程的前提条件，尽管增溶Tac所需的胆盐量比Tol多。Caco-2细胞对Tac具有水解活性，并且细胞可能摄取额外的胆固醇酯酶，从而提高Tac的细胞内水解速率。基于我们的研究结果，提出了一个解释肠细胞吸收α-生育酚乙酸酯的方案。
