Effect of 25-hydroxycholesterol, 26-hydroxycholesterol and its analogue, 26-aminocholesterol, on protein content, protein synthesis and LDH leakage in mouse epidermal cells

The cytotoxicity of 25-hydroxycholesterol, 26-hydroxycholesterol and its analogue, 26-aminocholesterol was investigated in murine epidermal cell line, HEL-30. Lactate dehydrogenase (LDH) leakage, protein synthesis and protein content were determined after exposure of cell monolayers to the compounds ranging from 0.1-200 μM for 2, 6 or 24 h. 26-Aminocholesterol affected all the parameters studied time and concentration dependently; 25-hydroxycholesterol and 26-hydroxycholesterol were not toxic for HEL-30 cells. The cellular target for 26-aminocholesterol was primarily the membrane, since the LDH leakage was already detectable 10 min after exposure. On the other hand, for the other two oxysterols a protective role on this structure might be postulated. In fact 25-hydroxycholesterol and 26-hydroxycholesterol decreased the natural LDH leakage due to the ageing of the culture. In addition, 20 μM 25-hydroxycholesterol reversed the effect of moderately lytic doses of 26-aminocholesterol and Triton X-100, but not of sodium dodecyl sulfate.