Protective effects of a hibernation-inducer on hepatocyte injury induced by hypothermic preservation.

Background/purpose: For hepatocyte-based cell therapy to be realistic, the method chosen for cryopreservation or hypothermic preservation is critical. The aim of the present study was to clarify whether D-Ala2-Leu5-enkephalin (DADLE), a hibernation inducer, has protective effects on hepatocytes with regard to hypothermic preservation injury.

Methods: A suspension of rat hepatocytes was stored at 4 degrees C for 24 h with or without DADLE. Their viability was measured by the trypan blue dye exclusion method, and alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels in the preservation solution were measured. After 24 h of cold storage, viable hepatocytes were cultured at 37 degrees C for another 24 h. Then albumin production and lidocaine clearance were measured.

Results: DADLE significantly improved the survival rate of hepatocytes. The levels of ALT and LDH in the preservation solution with DADLE were significantly lower than those in the preservation solution without DADLE. The treated viable hepatocytes maintained both albumin synthesis and lidocaine clearance.

Conclusions: DADLE appears to have protective effects on hepatocytes with regard to hypothermic preservation injury in vitro. This hibernation-inducer is useful in prolonged hypothermic preservation for hepatocyte-based therapy.