Expression of aquaporins in rat liver regeneration

The remarkable ability of liver to regenerate after insults has been harnessed by surgeons when designing techniques for liver resection or transplantation. However, the underlying mechanisms of liver regeneration are not fully clarified. On the other hand, aquaporins (AQPs) are small transmembrane proteins with unexpected physiological roles in addition to water transport. For example, they play pivotal roles in cell migration, angiogenesis, and cell proliferation, events that are also occurred during liver regeneration. We thus examined the possible involvement of AQPs in this regenerative process.

A two-thirds partial hepatectomy (PH) rat model was employed. The temporal expression of various AQPs in the liver following PH was determined by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blotting. The localization of AQPs was evaluated by immunohistochemistry.

As anticipated, AQP0, 8, 9, and 11 were detected mainly in hepatocytes; unexpectedly, Kupffer cells were observed to express AQP8 during a specific period of time in the regenerative process. AQP9 protein was shown to be expressed in a progressively enhanced pattern at early time points after PH. A transient expression of AQP11 in the nucleus of hepatocytes was observed.

These findings suggest the possibility that AQP might be involved in the PH-induced liver regeneration.