Di-rhamnolipids improve effect of trehalose on both hypothermic preservation and cryopreservation of rat hepatocytes

Trehalose, a disaccharide of glucose, is a highly hydrophilic small molecule (MW?=?342D) and a bioprotectant normally impermeable to the membrane phospholipid bilayer. Di-rhamnolipids, a major component of rhamnolipids, were applied to increase the effect of trehalose in cryopreservation and hypothermic preservation. We found that di-rhamnolipids (10 mg/L) increased the survival of hepatocytes after cryopreservation or hypothermic preservation as indicated by cell viability using trypan blue exclusion and methyl thiazolyl tetrazolium assay. Correspondingly, after hepatocytes were preserved in the presence of di-rhamnolipids, their hepatospecific functions were comparable to those of freshly cultured cells in terms of intracellular glutathione level, albumin secretion, urea production, and metabolic activities of cytochrome P450 isoforms. Measurement of trehalose intracellular concentration showed that its accumulation increased in the presence of di-rhamnolipids (10 mg/L) but was not altered by two other well-known surfactants, Tween-80, and Pluronic 127. Hence, di-rhamnolipids, which are non-toxic, effective, and commercially available, could be a promising protectant by potentiating the function of trehalose against hypothermic or cryopreservation cell damage.