Toxicological effects of pyraclostrobin on the antioxidant defense system and DNA damage in earthworms (Eisenia fetida)

Abstract

In recent years, pyraclostrobin has been widely used as a fungicide. However, pesticides remain in soil and water, potentially causing irreversible damage to non-target organisms. Thus, the present study investigated the toxicity of different pyraclostrobin concentrations (0, 0.1, 1.0, and 2.5 mg/kg) on earthworms (Eisenia fetida). On days 7, 14, 21, and 28, reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), glutathione-S-transferase (GST), and malondialdehyde (MDA) levels as well as DNA damage were evaluated. The ROS content under 0.1 mg/kg pyraclostrobin treatment first increased and later returned to the control level. High concentrations of pyraclostrobin (1.0 and 2.5 mg/kg) led to excessive ROS during the experiment. Enzyme activities and MDA contents in the experimental groups first increased and then decreased. Except for POD activity with 0.1 mg/kg pyraclostrobin treatment, SOD, POD, and GST activities under pyraclostrobin treatment were inhibited on day 28. However, CAT activities and MDA contents in the experimental groups were similar to control levels on day 28. DNA damage was promoted with increasing concentrations of pyraclostrobin. On days 21 and 28, DNA damage in earthworms treated with 0.1 mg/kg pyraclostrobin decreased. However, DNA damage in earthworms treated with 1.0 and 2.5 mg/kg pyraclostrobin rose slowly after the 14th day. In summary, pyraclostrobin can break the dynamic balance of ROS in the organism, which can affect the antioxidant defense system and ultimately cause DNA damage.