Cytotoxicity of linoleic acid peroxide, malondialdehyde and 4-hydroxynonenal towards human fibroblasts.

Lipid peroxidation occurs during oxidative stress and leads to the formation of various active compounds. However, controversy remains about its importance in the events leading to cell death. One approach to estimate their role in cell death would be to test the toxicity of oxidative products generated during the stress. In this work, three of these products were incubated with human fibroblasts and their toxicities were compared. The three compounds tested are: linoleic acid peroxide (LOOH), malondialdehyde (MDA) and 4-hydroxynonenal (HNE). Three cellular parameters were assayed: viability, DNA synthesis estimated by thymidine incorporation and protein synthesis measured by leucine incorporation. Protection against cellular damages was also tested adding alpha-tocopherol in the culture medium. The results showed that the peroxide was more toxic than HNE and much more than MDA. The possibility of initiation and propagation of the free radical chain reaction could explain this highest toxicity. The fibroblasts seem to be protected by alpha-tocopherol against LOOH. These effects emphasize the crucial role of this lipophilic antioxidant to protect cells against peroxidation damages.