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

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 12460057
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 食品科学・栄養科学
• Research Institution: KYOTO UNIVERSITY
• Principal Investigator: MATSUNO Ryuichi Graduated school of Agriculture, Professor, 農学研究科, 教授 (30032931)
• Co-Investigator(Kenkyū-buntansha): SHIMA Moohiro Graduated school of Agriculture, Instructor, 農学研究科, 助手 (60293916) ; KIMURA Yukitaka Graduated school of Agriculture, Instructor, 農学研究科, 助手 (70211878)
• Project Period (FY): 2000 – 2002
• Keywords: Absorption model / Absorption of a hydrophobic substance / Caco-2 cells

Research Abstract

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.