stellate cells (HSCs) are known to play a role in hepatic regeneration.
We investigated hepatocyte/HSC interaction and HSC activation at
various times after 70% partial hepatectomy (PHx) in the rat.MethodsThe
hepatic microcirculation was studied using intravital fluorescence
microscopy (IVFM). Desmin and α-SMA within liver tissue were detected by
immunohistochemistry. In isolated parenchymal liver cells (PLCs) and
HSCs, double immunostaining was used to identify activated HSC.ResultsUsing
IVFM, hepatocyte-clusters were often seen in vivo at 3 days after PHx
(PHx3). Distance between HSC fell from 61.7±2.1 μm in controls to
36.1±1.4 μm (P<0.001) while the HSC/hepatocyte ratio rose (0.71±0.01 to 1.08±0.03; P<0.001).
In >80% of in vivo microscopic fields in the PHx3 group, clusters of
HSCs were observed especially near hepatocyte-clusters. At PHx1 and
PHx3, >20% of cells in the PLC-fraction were HSCs which adhered to
hepatocytes. At PHx3, in addition to desmin staining, isolated HSCs were
also positive for BrdU and α-SMA, and formed clusters. HSCs in the
HSC-fraction were only positive for desmin which indicated that
adherence to hepatocytes is required for HSC activation.ConclusionsOur data suggest that HSCs are activated by adhering to hepatocytes in the early phase of liver regeneration.