Diclofenac (DCF), one of the most current and widely used nonsteroidal anti-in ammatory drugs (NSAIDs), has been frequently detected in aquatic environments worldwide. However, the ecotoxicological effects of DCF on freshwater invertebrates remain largely unknown. In the present study, Corbicula uminea were exposed to environmentally relevant concentrations of DCF (0, 2, 20 and 200 µg/L) for 28 days, and the potential adverse effects of DCF on siphoning behavior, antioxidant responses and apoptosis were investigated. Our results showed that the siphon e ciencies of clams were signi cantly suppressed by DCF exposure. DCF exerted neurotoxicity via reducing the activity of acetylcholinesterase (AChE) in gills and digestive gland of C. uminea. Exposure to DCF induced antioxidant stress and led to increased malondialdehyde (MDA) levels in both tissues of C. uminea. Transcriptional alterations of apoptosis-related genes indicated that DCF might induce apoptosis by triggering mitochondrial apoptotic pathway. Our ndings will help enhance our awareness of the negative effects of DCF on freshwater bivalves and highlight the ecological risks of DCF in freshwater ecosystems.

Diclofenac (DCF), one of the most current and widely used nonsteroidal anti-inflammatory drugs (NSAIDs), has been frequently detected in aquatic environments worldwide. However, the ecotoxicological effects of DCF on freshwater invertebrates remain largely unknown. In the present study, Corbicula fluminea were exposed to environmentally relevant concentrations of DCF (0, 2, 20 and 200 µg/L) for 28 days, and the potential adverse effects of DCF on siphoning behavior, antioxidant responses and apoptosis were investigated. Our results showed that the siphon efficiencies of clams were significantly suppressed by DCF exposure. DCF exerted neurotoxicity via reducing the activity of acetylcholinesterase (AChE) in gills and digestive gland of C. fluminea. Exposure to DCF induced antioxidant stress and led to increased malondialdehyde (MDA) levels in both tissues of C. fluminea. Transcriptional alterations of apoptosis-related genes indicated that DCF might induce apoptosis by triggering mitochondrial apoptotic pathway. Our findings will help enhance our awareness of the negative effects of DCF on freshwater bivalves and highlight the ecological risks of DCF in freshwater ecosystems.