Microanatomy and behaviour of the date mussel's adductor and foot muscles after chronic exposure to bisphenol A, with inhibition of ATPase enzyme activities and DNA damage

Abstract

Environmental contaminants with estrogenic activity have recently received attention due to the potential harm they could cause to humans and wildlife. To assess the toxic effects of bisphenol A (BPA) on marine mussels, Lithophaga lithophaga were exposed for 4 weeks to 0, 0.25, 1, 2, and 5 μg/L BPA. Aside from DNA damage, a behavioural study including valve closure duration (VCD), valve opening duration (VOD), levels of malondialdehyde (MDA), and total glutathione, as well as superoxide dismutase (SOD) and ATPase activities in adductor muscle extracts, and histopathological examination of the adductor muscle and foot were performed. The behavioural response was marked by an increase in the percentage of VCD and a decrease in the percentage of VOD during 8 h. Furthermore, BPA treatments resulted in a significant concentration-dependent increase in muscle MDA and total glutathione levels. However, when compared to controls, SOD and ATPase activity was significantly reduced in the adductor muscles of BPA treatments. Histological examination of the adductor and foot muscles revealed qualitatively distinct abnormalities. DNA damage was strongly induced in a concentration-dependent manner. Our findings suggested that BPA exposure altered detoxification, antioxidation, ATPase activity, histopathological characteristics, and DNA damage, which resulted in behavioural changes. The multi-biomarker approach used suggests that clear relationships exist between genotoxic and higher-level effects in some cases, which could be used as an integrated tool to evaluate various long-term toxic effects of BPA.