Design of the in vitro model with a cultured intestinal cell monolayer and pseudo lymph and blood streams for assessment of the absorption of a hydrophobic substance

在体内，疏水物质从肠道吸收到血液或淋巴中。本项目旨在设计一种简单的体外模型，可以与体内吸收过程相比较，利用培养的分化细胞层独立控制血流和淋巴流。本研究的主要内容是分析疏水性物质对细胞和通过细胞层的吸收情况。研究发现，疏水物质积累到细胞层中，由于两种物质之间的静电相互作用阻止了物质的酶解，加快了吸收速度，因此有可能通过添加另一种具有反电荷的疏水物质来改善疏水物质的吸收，因为疏水物质容易被消化酶分解并带有电荷。并详细分析了具有抗氧化性能的抗坏血酸酰基化合物在细胞层的吸收情况，包括非酶解过程。此外，还发现酰基抗坏血酸酯对从肠腔侧到肠道吸收细胞Caco-2的抗氧化剂具有很强的抗氧化性能。三尖杉酯是一种较好的假性淋巴成分。选择了膜过滤器，以便于将疏水物质从亲水性溶液(适用于血液)传输到疏水性溶液(适用于淋巴)。此外，还验证了输液泵可以控制溶液流入血侧隔室的流量，并确定了小隔室完全混合的搅拌条件。这些发现将使建立评估疏水物质吸收的体外模型成为可能。

The hydrophobic substance is absorbed from the intestinal tract into the blood or lymph in vivo. This project intended to design the simple in vitro model which can be compared with the absorption process in vivo and independently control the blood stream and the lymph stream making use of the cultured cell layer which differentiates.Most part of this research was analysis of absorption of the hydrophobic substance to the cells and through the cell layer. It was found that the hydrophobic substances accumulated into the cell layer and that there was a possibility to improve the absorption of a hydrophobic substance, which is easily decomposed by digestive enzymes and possesses an electric charge, by adding another hydrophobic substance which possesses the counter electric charge because the electrostatic interaction between both substances prevented enzymatic hydrolysis of the substance and accelerated the absorption rate. And the absorption of acyl ascorbates, which possess an anti-oxidation property, to the cell layer was also analyzed in detail including the non-enzymatically hydrolytic process. Furthermore, it was found that the acyl ascorbates granted a strong anti-oxidation property against the oxidant from the lumen side to the intestinal tract absorption cell, Caco-2.The various conditions necessary for model construction were examined. Tricaprylin was one of the good compounds as a pseudo lymph component. A membrane filter was selected for the easy transmit of a hydrophobic substance from the hydrophilic solution (suitable to the blood) to the hydrophobic solution (suitable to the lymph). In addition, it was verified that the influx outflow of the solution to the compartment of blood side can be controlled with an infusion pump and was decided the churning condition for complete mixing of the small compartment. These findings would enable the construction of the in vitro model for assessment of the absorption of a hydrophobic substance.