Isolation and Expansion of Rat Hepatocytic Progenitor Cells.

This protocol showed procedures to isolate and expand small hepatocytes (SHs), as hepatocytic progenitor cells, from a rat liver. SHs are identified as a subpopulation of mature hepatocytes in a healthy liver. SHs can proliferate to form colonies in serum-free medium on hyaluronic acid-coated dishes, of which cells show CD44 positivity (CD44+ SHs). CD44+ SHs can be separated and purified from colonies by using anti-CD44 antibodies after enzymatic dissociation. CD44+ SHs can proliferate to form colonies on Engelbreth-Holm-Swarm gel (EHS-gel)-coated dishes in the serum-free medium for a long period and subculture for several times. Even after the second passage, the cells possess characteristics of hepatocytes such as expression of albumin and HNF4α. In addition, when the cells are treated with EHS-gel, they can recover highly differentiated functions of hepatocytes such as glycogen production, CYP activity, and bile secretion.