Annexin A3-expressing cellular phenotypes emerge from necrotic lesion in the pericentral area in 2-acetylaminofluoren/carbon tetrachloride-treated rat livers.

Recently we found a small hepatocyte-specific protein, annexin A3 (AnxA3), in fractionated adult rat hepatocytes. Here we describe the results of an in vivo demonstration of AnxA3-expressing cellular phenotypes in the liver with 2-acetylaminofluoren (2-AAF)/carbon tetrachloride (CCl(4))-injury. In association with an elevation of alanine amino transferase (ALT) and aspartic acid amino transferase (AST) activities, hepatic AnxA3 mRNA increased markedly. AnxA3-positive cells were detected in clustered cells present in or emerging from the pericentral region. These albumin-expressed cells were histologically similar to cells expressing CD34, a hematopoietic cell marker protein. The number of clusters decreased in the days following CCl(4) treatment, and annexin-negative, but albumin-positive, oval cells appeared. We concluded that the agent-induced liver defect initially recruits bone marrow-derived cells, and that it promotes differentiation of these cells into AnxA3-positive cells, followed by emergence of the oval cells, which might have a role in the restitution of the damaged liver.