A multibiomarker approach to explore interactive effects of propranolol and fluoxetine in marine mussels

A multi-biomarker approach, including several lysosomal parameters, activity and mRNA expression of antioxidant enzymes, and DNA damage, was employed to investigate the nominal effects of 0.3 ng/L fluoxetine (FX) and 0.3 ng/L propranolol (PROP) alone or in combination (0.3 ng/L FX þ 0.3 ng/L PROP) on Mediterranean mussels after a 7 day treatment. FX co-exposure appears to facilitate PROP bio- accumulation because PROP only accumulated in digestive gland of FX þ PROP treated mussels. Lyso- somal parameters were significantly impaired by FX þ PROP treatment, while no clear antioxidant responses at the catalytic and transcriptional levels were observed. Biomarker responses led to a “me- dium stress level” diagnosis in FX þ PROP treated mussels, according to the Expert System, whereas 0.3 ng/L PROP or FX alone did not induce consistent stress conditions. These findings suggest vulnera- bility of coastal marine mussels to FX and PROP contamination at environmentally relevant levels.