DESMIN EXPRESSING NONHEMATOPOIETIC LIVER-CELLS DURING RAT-LIVER DEVELOPMENT - AN IMMUNOHISTOCHEMICAL AND MORPHOMETRIC STUDY

The expression and cellular distribution of desmin, alpha-smooth muscl e actin (A-SMA) and cytokeratin no. 8 (CK-8) and no. 18 (CK-18) in nor mal adult, neonatal and fetal rat liver were examined immunohistochemi cally on cryostat sections. At days 14 and 15 of gestation, nonhematop oietic cells in embryonic liver were strongly desmin-positive, and som e of the cells, mainly located in the periphery, were also stained wit h anti-A-SMA. Desmin immunoreactivity gradually decreased from day 16 of gestation. A close association of desmin-positive cell processes wi th hematopoietic cells was observed during fetal and early neonatal de velopment. From day 16 of gestation the prehepatocytes became desmin-n egative, remained CK-8 and CK-18 positive. Desmin-expressing cells wer e numerous in the liver from the embryonic period to the neonatal age. However, their absolute number per unit area, as well as their number relative to hepatocytes, decreased with age. We suggest that desmin-p ositive cells in embryonic liver may act as stromal cells in the hepat ic hematopoietic microenvironment and support hepatocyte development.