Biochemical marker analysis of Unio tumidus response to Roundup, chlorpromazine and elevated temperature applied separately and jointly

Abstract

Bivalve molluscs represent the most recognised bioindicators of freshwater pollution. However, their ability to indicate specific xenobiotics in complex exposures is unclear. This study aimed to explore the effects of common pollutants, pesticide Roundup (Rn) and antipsychotic drug chlorpromazine (Cpz) on the mussels Unio tumidus at environmentally relevant concentrations. The mussels were treated separately to Rn (17 µg L−1) and Cpz (18 µg L−1) and jointly to Rn and Cpz at 18 oC (RnCpz) as well as to Rn at 25 oC (RnT). Digestive glands were examined after 14 days of exposure. Shared responses were the increase of the level of Zn-metallothioneins and antioxidant activity (ABTS test) in all groups, the increases of the GSH/GSSG ratio, protein carbonyls, CYP450 related activity (EROD) (by three times in RnT- and Cpz-groups), and citrate synthase activity in the RnT-, RnCpz- and Cpz-groups, and increase of metallothionein protein concentration in all groups except Cpz. Cholinesterase and caspase-3 activities increased in Rn- and RnCpz- groups and GST in Rn-group. Cpz caused a decrease in GST activity and Zn level in the tissue and an increase in lysosomal integrity. The highest injury was indicated in the RnT-group due to the decrease of lysosomal integrity. According to discriminant analysis, Rn- and control groups were less different, Cpz caused major response diverseness, and complex exposures abolished the individual response traits. Summarising, multi-marker expertise with the application of integrated indices has benefits when evaluating the effects of complex exposures