The Potential Effect of Silver Nanoparticles on the Expression and Levels of Skin Matrix Metalloproteinases (Gelatinases): In Vivo Assessment

Abstract

The current work aimed to investigate the enzymatic activities and the expression profiles of the metalloproteinases MMP-2 and MMP-9 in the skin of rabbits as an animal model, upon sub-acute dermal exposure to Ag-NPs. This was done in order to determine their potential effect on these proteolytic enzymes which have been traditionally involved in many physiological processes such as inflammation and wound healing which are among the main applications Ag-NPs containing medical products. The rabbits were topically exposed to every other day dose of 0.5% Ag-NPs for 7- and 14-days experimental periods. Both periods were followed by 7 days recovery time. The results revealed the remarkable effect of Ag-NPs on MMPs at both the enzyme production and the transcriptional levels. The effect was time dependent where no significant changes were found after the 7 days of exposure, while the concentrations of MMP-2 and MMP-9 as well as the expression of their encoding genes were significantly elevated in the skin of the exposure and recovery groups at the 14 days experimental period. MMP-9 was the most affected enzyme, whereas MMP-2 showed the minimal effect. Several mechanisms and pathways have been suggested to explain the disturbance of MMPs which require further molecular studies to obtain more evidence supporting the most probable explanation.