An electron microscope study of developing bile canaliculi in the rat,

Abstract

The development of bile canaliculi and the sequence of appearance of pericanalicular bodies has been explored by electron microscopy. The first bile canaliculi appear on about the thirteenth embryonic day in close association with linear attachment zones between adjacent hepatic cells. These canaliculi are formed by only two apposed cell surfaces and the configuration of a central biliary lumen bounded by 4-5 contiguous cells described classically as typical for developing mammalian liver is not apparent until day 16 or 17. The enlarged biliary spaces apparently arise as separate vesicles or saccules which subsequently elongate into tubules and interconnect. Evidence obtained in this study supports the concept that terminal bile ductules develop by direct transformation of tubular channels lined by hepatic cells under the influence of periportal connective tissue. Pericanalicular bodies develop in association with an hypertrophied Golgi zone. The sequence of appearance is: multivesicular bodies, microbodies, typical lysosomes. There is no evidence from this study that microbodies arc related to differentiating mitochondria but the chronology of appearance suggests a close relationship to lysosomes.

Development of the Bile Canalicular System in Rat Liver: with Special Reference to Bile Canalicular Actin Filaments and Mg2+, Ca2+-ATPase Activity.

“…The prominent organ of the rat liver appears from the 11th-12th day of gestation (8,36). The early form of BC was detected from the 12th-13th day of gestation by electron microscopic observation (36).…”

“…The early form of BC was detected from the 12th-13th day of gestation by electron microscopic observation (36). However, no information is available about the formation of bile canalicular F-actin at these early stages.…”

FGF signaling segregates biliary cell‐lineage from chick hepatoblasts cooperatively with BMP4 and ECM components in vitro

“…BECs originate from bipotential hepatoblasts, which can also differentiate into mature hepatocytes (Shah and Gerber, 1989;Shiojiri, 1994;Haruna et al, 1996). The portal mesenchyme is believed to induce hepatoblasts to differentiate into BECs (Wilson et al, 1963;Wood, 1965;Enzan et al, 1974;Shiojiri, 1984). Major components of the extracellular matrix (ECM) of the portal mesenchyme, such as collagen, fibronectin, and laminin, may be involved in the induction of bile duct differentiation (Shah and Gerber, 1990;Baloch et al, 1992;Shiojiri and Nagai, 1992;Terada and Nakanuma, 1994).…”

Cell Lineage Analysis during Liver Development Using the spfash-Heterozygous Mouse

“…differentiation (Doljanski and Roulet, 1934;Wilson et al, 1963;Wood, 1965), which could be equivalent in its potential to differentiate into hepatocytes and biliary epithelial cells. It has been stated that periportal connective tissue is crucial for bile duct differentiation (Doljanski and Roulet, 1934;Wilson et al, 1963), but its mechanism is still uncertain.…”

“…Thus, at around 15.5 days of gestation, biliary cell progenitors and hepatocyte progenitors may already be determined in mouse liver development. Because intrahepatic bile duct development continues during the remainder of fetal life along the developing branches of the portal vein towards the periphery of the liver organ (Wilson et al, 1963;Wood, 1965), commitment or determination of biliary cells may proceed successively. In any event, experimental studies, such as clonal cultures of hepatoblasts for strict demonstration of the differentiation potency of each hepatoblast, are required in the future.…”