Thiol-Containing Antioxidants Reduce Accumulation of Collagen I on the Surface of Human Skin Fibroblasts

— The effects of the antioxidants N-acetylcysteine (NAC), a pair of α-lipoic (LA) and dihydrolipoic (DHLA) acids on human skin fibroblasts in vitro was compared. More specifically, we tried to determine changes in the generation of active oxygen species (ROS), activity of matrix metalloproteinases (MMP-1 collagenase and MMP-2 and MMP-9 gelatinases), and accumulation of collagen I on the surface of cultured cells. Here, we showed that NAC decreased both ROS level in cells (detected by an H 2 DCFDA fluorescent probe) and activity of all MMPs in the culture medium. In contrast to NAC, LA and DHLA did not change ROS level and increased the activity of collagenase MMP-1, but had little effect on the gelatinase activity. At the same time, the amount of collagen I on the cell surface was reduced by about 20% in the presence of NAC and DHLA. Taken together, our findings indicate that, under normal physiological conditions, antioxidants are able to interfere with the composition/properties of the extracellular matrix.