Date Published: February 2, 2017
Publisher: Public Library of Science
Author(s): Marcelo Verdugo, Jorge Ruiz Encinar, José Manuel Costa-Fernández, Mario Menendez-Miranda, Diego Bouzas-Ramos, Manuel Bravo, Waldo Quiroz, Jamshidkhan Chamani.
Antimony is a metalloid that affects biological functions in humans due to a mechanism still not understood. There is no doubt that the toxicity and physicochemical properties of Sb are strongly related with its chemical state. In this paper, the interaction between Sb(III) and Sb(V) with bovine serum albumin (BSA) was investigated in vitro by fluorescence spectroscopy, and circular dichroism (CD) under simulated physiological conditions. Moreover, the coupling of the separation technique, asymmetric flow field-flow fractionation, with elemental mass spectrometry to understand the interaction of Sb(V) and Sb(III) with the BSA was also used. Our results showed a different behaviour of Sb(III) vs. Sb(V) regarding their effects on the interaction with the BSA. The effects in terms of protein aggregates and conformational changes were higher in the presence of Sb(III) compared to Sb(V) which may explain the differences in toxicity between both Sb species in vivo. Obtained results demonstrated the protective effect of GSH that modifies the degree of interaction between the Sb species with BSA. Interestingly, in our experiments it was possible to detect an interaction between BSA and Sb species, which may be related with the presence of labile complex between the Sb and a protein for the first time.
Antimony is widely used in the manufacture of different goods, such as flame retardants, catalysers, munitions and as an anti-parasitic drug against Leishmaniasis. Additionally, one of the main sources of Sb pollution comes from the wear on vehicle braking systems which generates atmospheric particulate matter (APM) with high Sb content[2,3]. High levels of Sb enrichment in APM have been reported in Tokyo, Buenos Aires and Valparaiso, finding a significant Sb enrichment in the blood of workers exposed to heavy vehicle traffic. Recent studies have reported the toxic behaviour of antimony. As an example, in a recent study it has been shown that Sb(V) and Sb(III) are able to penetrate the erythrocyte membrane to reach the cytoplasm. Chronic exposure to Sb can cause irritation of the eyes and skin and even cancer of the kidney, liver and lungs.
Based on the evidence gathered in this study, it can be stated that Sb(III) generates conformational changes in the structure of the protein BSA, while Sb(V) does not. In addition, GSH is a protective agent against the effects of Sb on protein conformational changes.