Bisphenol A is one of the most widespread chemicals in the world. Due to its massive production and applications it is ubiquitous in the environment and various consumer products used daily. Human exposure to bisphenol A has become practically unavoidable. Bisphenol A is a well-known endocrine disruptor and exhibits many toxic effects on living organisms. Publication of studies demonstrating its toxic effects was followed by regulations of its production or complete prohibition of its use in various applications. The regulations were followed by introduction of structurally similar chemicals, with similar physio-chemical properties, called bisphenol analogues on the global market. But the question arises, if bisphenol analogues are also safer for the environment and if their exposure to humans is less hazardous. Due to their widespread occurrence, human co-exposure to multiple bisphenol analogues should also be researched. Among all the bisphenols currently used in industrial applications, bisphenol A is the most ubiquitous and most researched, followed by bisphenols S, F and AF. Most studies are focused on their toxic effects exhibited via their disruption of endocrine system, while not many data exist regarding their genotoxicity. In our research we examined cytotoxic and genotoxic potential of bisphenols A, S, F, AF and their complex mixtures on human hepatoma cell line (HepG2). To determine their cytotoxicity MTS test was used. For determination of their genotoxic activity we analyzed the presence of DNA double strand breaks, by indirect detection of γ-H2AX foci using flow cytometry. We examined bisphenols A, S, F and AF respectively at different concentrations after 24- and 72-hour exposure of HepG2 cells to each chemical. We also assessed cytotoxic and genotoxic activity of complex mixtures of bisphenol analogues on HepG2 cells, at concentrations that are found in the environment and concentrations relevant for human exposure after 24-hour and 72-hour exposure time. The results of our research showed that bisphenol AF exhibited the highest cytotoxic effect in HepG2 cells, whereas the least cytotoxic was bisphenol A. Bisphenol A did not reduce cell viability at any of the tested concentrations after 24- nor 72-hour exposure. Bisphenols F and AF exhibited the highest genotoxic effect. After 24-hour exposure time they caused an increase in DNA double strand breaks at concentrations 10 μg/mL and 20 μg/mL. After 72-hour exposure time bisphenol F caused an increase in DNA double strand breaks at concentration 20 μg/mL, whereas bisphenol AF did not show any genotoxic effect at non-cytotoxic concentrations. Bisphenol A induced an increase in DNA double strand breaks in HepG2 cells at the highest tested concentration (20 μg/mL) after 72-hour exposure time. The least genotoxic was bisphenol S which did not induce an increase in DNA double strand breaks in HepG2 cells after 24-hour nor 72-hour exposure time. Exposure of the HepG2 cells to complex mixtures of bisphenols A, S, F and AF at concentrations relevant for the environment and human exposure, did not affect cell viability, neither induce an increase in DNA double strand breaks, after 24-hour nor 72-hour exposure time.
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