| Research Abstract |
In this study, the role of extracellular matrix (ECM) which presents in intracellular space of non-parenchymal hepatic cells was evaluated in remodeling after hepatectomy. Because, it has not been well known about the roles of most of ECM in liver. Especially, tenascin is one of the ECM. However, there was few reports about expression of tenascin in liver. Thus, we determined the mechanism of remodeling of remnant liver following liver resection, focusing on the role of tanascin.
The regeneration rates of remnant liver in tenascin (TN)-knockout mouse were significantly higher than those of wild type mouse (control mouse) at 1,2,3,4 weeks after 70% hepatectomy (TN-knock out group : 83.3, 94.4, 99.5, 101.9%, control group : 66.2, 75.3, 77.1, 79.2% respectively). Additionally, there were no difference between TN-knockout mouse and control mouse in protein content and DNA concentration of remnant liver. Thus, it is suggested that the expression of TN in remnant liver controls the remodeling the structure of remnant liver and down-regulates the regeneration of liver.
In immunopathological findings, TN-protein was strongly expressed in sinusoidal space around the central vein of remnant liver a week after liver resection. Using the technique of in situ hybridization, the expression of TN-mRNA was evaluated after liver resection. TN-mRNA was strongly expressed in sinusoidal wall, especially Ito cell a week following hepatectomy. On the other side, The expression of other ECMs such as laminin was not shown at central vein. These ECMs expect TN were expressed at portal area and bile duct wall cell. There was complete difference between TN and other ECMs on the roles of remodeling of remnant liver regeneration following liver resection.
These results suggested that TN has the role of inhibiting the hepatic cell regeneration. Thus, expression on TN has the role of control and/or down-regulation in regeneration and remodeling of remnant liver following resection.
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