An In Vitro Comparative Study of the Effects of Tetrabromobisphenol A and Tetrabromobisphenol S on Human Erythrocyte Membranes—Changes in ATP Level, Perturbations in Membrane Fluidity, Alterations in Conformational State and Damage to Proteins

Abstract

Brominated flame retardants (BFRs) are substances used to reduce the flammability of plastics. Among this group, tetrabormobisphenol A (TBBPA) is currently produced and used on the greatest scale, but due to the emerging reports on its potential toxicity, tetrabromobisphenol S (TBBPS)—a compound with a very similar structure—is used as an alternative. Due to the fact that the compounds in question are found in the environment and in biological samples from living organisms, including humans, and due to the insufficient toxicological knowledge about them, it is necessary to assess their impacts on living organisms and verify the validity of TBBPA replacement by TBBPS. The RBC membrane was chosen as the research model. This is a widely accepted research model for assessing the toxicity of xenobiotics, and it is the first barrier to compounds entering circulation. It was found that TBBPA and TBBPS caused increases in the fluidity of the erythrocyte membrane in their hydrophilic layer, and conformational changes to membrane proteins. They also caused thiol group elevation, an increase in lipid peroxidation (TBBPS only) and decreases in the level of ATP in cells. They also caused changes in the size and shape of RBCs. TBBPA caused changes in the erythrocyte membrane at lower concentrations compared to TBBPS at an occupational exposure level.

Binding of Tetrabromobisphenol A and S to Human Serum Albumin Is Weakened by Coexisting Nanoplastics and Environmental Kosmotropes

“…Although the toxicity of TBBPS seems to be weaker than that of TBBPA in terms of cytotoxicity, neural developmental toxicity, and DNA damage in different cell lines, they all induce reactive oxygen species (including hydroxyl radical) formation and cause oxidative damage to proteins . Also, they were found to increase the fluidity of the erythrocyte membrane and cause ATP depletion and conformational changes to membrane proteins . Special concerns have been raised due to the frequent detection of TBBPA and TBBPS residues in blood serum samples from the Chinese population .…”

“…10 Also, they were found to increase the fluidity of the erythrocyte membrane and cause ATP depletion and conformational changes to membrane proteins. 11 Special concerns have been raised due to the frequent detection of TBBPA and TBBPS residues in blood serum samples from the Chinese population. 12 TBBPA was also found in the plasma of Japanese and French males, females, and fetuses with concentrations up to 950 pg/g fresh weight.…”

Assortment of Frontiers in Protein Science

“…The toxicity of tetrabromobisphenol-S (TBBPS) was investigated by Jarosiewicz et al [ 19 ], in order to see whether it would be a proper replacement for the widely used flame retardant tetrabromobisphenol-A (TBBPA), which is potentially toxic. They used red blood cell membranes as a model system.…”