Effects of cypermethrin on the clams Ruditapes philippinarum (A. Adams & Reeve, 1850).

Abstract

Cypermethrin, highly toxic to aquatic life, impacts Ruditapes philippinarum (A. Adams & Reeve, 1850), an economically valuable species. Thus, studying its toxicity mechanism to R. philippinarum is crucial. In this research, R. philippinarum was exposed to 5000 ng/L cypermethrin and sampled on days 0, 1, 3, 6, 10, 15, and 21 to assess enzymatic activities and conduct transcriptome sequencing. The enzymatic activity results showed that cypermethrin could increase the activity of the ethoxyresorufin-O-deethylase (EROD), turn on the antioxidant defenses, cause an initial increase in total antioxidant capacity (T-AOC) and then a decrease, increase the activities of antioxidant enzymes catalase (CAT) and glutathione peroxidase (GPx), and inhibit superoxide dismutase (SOD). Furthermore, the contents of malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) increased in the body at 10, 15, and 21 days of exposure. Transcriptome sequencing was carried out to analyze the responses of cypermethrin stress for 1 day and 21 days. Differentially expressed genes (DEGs) were linked to detoxification metabolism and oxidative stress, according to Gene Ontology (GO) enrichment analysis. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis demonstrated that cypermethrin had toxic effects through key factors affecting detoxification metabolism, oxidative stress, immune response, and apoptosis-related pathways. This study gives insights into the harmful mechanism of cypermethrin stress on R. philippinarum, as well as a theoretical basis for assessing the ecological danger of cypermethrin in Chinese coastal waters.