RESUMO
BACKGROUND: The morphological characteristics of hepatocytes transplanted into the spleen have been studied. However few attempts has been made to determine the expression of genes in intrasplenically transplanted hepatocytes. The aim of this study was to explore whether the pattern of expression of albumin gene in intrasplenically transplanted hepatocytes is similar to that in adult liver, resulting in the long-term expression of this hepatocyte-specific gene. METHODS: Hepatocytes isolated from liver of syngeneic Fischer 344 rats and transplanted into the spleen of rats from the same strain survived for 12 months in the absence of immunosuppressive drugs. Microscopic examination of intrasplenic hepatocytes and Northern blotting for albumin gene expression of RNA extracted from liver and spleen was performed. RESULTS: Microscopy demonstrated that hepatocytes attached themselves only in the red pulp of the spleen and isolated hepatocytes preserved the fine structures characteristic of normal hepatic parenchymal cells. Throughout the 12 months period, intrasplenically transplanted hepatocytes expressed albumin mRNA. CONCLUSIONS: Intrasplenically transplanted hepatocytes represent a unique in vivo system of extrahepatic maintenance of hepatocytes. This novel transplantation system could be used to investigate hepatocyte engraft, proliferation and gene expression.