Differential scanning calorimetry of human and animal stratum corneum membranes

Thermal transitions in desiccated stratum corneum membranes of neonatal rats, mice and rabbits and adult abdominal human skin were investigated using differential scanning calorimetry (DSC). Four endothermic transitions at 39-45 (T1), 55-58 (Tx), 68-74 (T2) and 77-86 degrees C (T3), were observed. T1, T2 and T3 were attributed to phase changes in the intercellular lipid bilayers. Tx was a weak transition, the exact nature of which is unknown. A fifth transition at 48 degrees C (Ty) was only observed with neonatal rabbit stratum corneum and was attributed to lipid melting. The DSC results indicated that the temperatures of lipid transitions of human and animal tissues were different although the patterns of their thermograms were similar. The temperatures of T2 and T3 of human stratum corneum were higher than those of the animals. DSC of neonatal rabbit stratum corneum showed a lipid transition not seen in stratum corneum of human or other animal species. (C) 1998 Elsevier Science E.V. All rights reserved.