RESUMO
The tolerance and cryoprotective effect of propane-1,2-diol on human skin was evaluated using tetrazolium reductase enzyme activity to assess tissue viability. The tolerance of human skin was tested by exposing the skin to increasing concentrations of propane-1,2-diol (10, 20, and 40% v/v), at two permeation temperatures (4 degrees C or room temperature), in a stepwise manner, to reduce osmotically induced changes in cell volume. There was no evidence of specific toxicity attributable to the cryoprotectant during the permeation period, even at a concentration of 40%; however a significant decrease in human skin viability was observed after freezing and thawing with high concentrations of cryoprotectant. The only useful protocol was that employing a low cooling rate (-1 degree C min-1) with 10 or 20% (v/v) propane-1,2-diol at a low permeation temperature. The data suggest that propane-1,2-diol does not produced improved results when compared with other cryoprotectants used for skin cryopreservation.
