Antioxidant action on the level of reactive oxygen species in normal and transformed fibroblasts

The level of reactive oxygen species (ROS) in normal (3T3) and transformed (3T3-SV40) murine fibroblasts treated with antioxidants for 15 min was studied using a carboxy-H 2 DCFDA fluorescent probe. It was shown that N-acetylcysteine (NAC) decreased the ROS level in both cell types. Antioxidant alpha-lipoic acid (ALA) and its reduced form dihydrolipoic acid (DHLA) caused a pro-oxidant effect. ALA and DHLA in the concentration range from 0.1–1.25 mM increased the ROS level in a dose-dependent manner in both cell types. The ability of ALA and DHLA to activate hydrogen peroxide production is discussed.