An ex vivo biochemical model to study the antioxidant clinical properties of cosmetic products in human antiaging skin care

It is generally accepted that lipid peroxides play an important role in the pathogenesis of free radical-induced cellular injury and that endogenous t hiois are vital in cellular defense against oxidative stress. The purpose o f this study was to investigate in cultured human skin fibroblasts the effe ct of oxidative stress on the synthesis of heat shock protein (HSP70) and o n the sulfhydryl group content in the absence and presence of a-tocopherol as an antioxidant compound. The interesting observation emerging from this study was a marked increase in malonaldehyde and fluorescent peroxide level s associated with a significant thiol depletion and induction of HSP70 stre ss proteins observed in primary cultures of normal human skin fibroblasts s ubjected to heat shock or incubated with hydrogen peroxide. These changes w ere significantly reduced in the presence of cl-tocopherol. Our findings su ggest a correlation between the mechanisms of oxidative stress, antioxidant s and HSP70 induction, which can be assessed to evaluate either the perturb ation of skin oxidant/antioxidant balance or the protection afforded by ant ioxidant test compounds.