Isolation and characterization of reticulum fibers and portal tract connective tissue of the normal human liver - With a special emphasis on collagen composition-

Intralobular (A) and interlobular (B) tissue fragments of the liver were separated from normal human liver tissue by tissue fractionation with a metal mesh. Connective tissue extracted from A was composed of reticulum fibers and that from B was thick and contained vascular structures, and a small amount of muscle and elastic fibers. It was revealed by histological methods that the tissue fragments and connective tissues retained the integrity of intra- and interlobular tissue as observed in vivo. These connective tissues were solubilized with either pepsin in acetic acid or 4 M guanidine-HCl, and analyzed for the amount of collagen, neutral sugar, fibronectin, laminin and hexuronic acid. Pepsin digestion resulted in solubilization of about 70% of total collagen. Collagen type analysis revealed that 29% was type I, 28% was type III and 43% was the other types in intralobular connective tissue, and that 42% was type I, 29% was type III and 29% was the other types in interlobular connective tissue. Guanidine-HCl extraction resulted in solubilization of 32.4% (A) and 22.1% (B) of total neutral sugar. The concentration of fibronectin and laminin in the guanidine extract were 16.4 μg and 53.6 ng per 1 g of A, and 3.4 μg and 157.0 ng per 1 g of B. Guanidine-HCl extraction resulted in solubilization of 41.8% (A) and 24.2% (B) of total hexuronic acid, which accounted for 3.1 mg/g and 1.3 mg/g, respectively. These results indicated that the two connective tissues histologically defined as intralobular and interlobular connective tissue were different in the amount of components.