大量腸管切除にて腸管細胞内レチノール結合タンパク質 II およびアポリポ タンパク質 A-IV の遺伝子発現が上昇しラット腸管におけるビタミン A 環境 を変化させる

摘要

Short bowel (SB) syndrome causes the malabsorption of various nutrients. Among them, vitamin A isimportant for many physiological activities. Vitamin A is taken up by absorptive epithelial cells of the smallintestine and discharged into lymphatics as a component of chylomicrons and delivered to the liver. Here, weused a rat model of SB syndrome to assess its effects on the expression of genes associated with theabsorption, transport and metabolism of vitamin A. In SB rats, intestinal expression levels of mRNAs forcellular retinol-binding protein II (CRBP II, gene symbol Rbp2) and apolipoprotein A-IV (gene symbolApoa4) were higher than in shams. Absorptive epithelial cells stained positively for both CRBP II andlecithin:retinol acyltransferase, both needed for effective esterification of vitamin A. In SB rats, the ilealretinol content and the jejunal retinyl esters content were lower than in sham rats. These results suggest thatthe elevated expression levels of Rbp2 and Apoa4 mRNAs in SB rats contribute to the effective esterificationand transport of vitamin A.