Effects of Arsenic Exposure on Oxidative and Cellular Stress in Lymnaea stagnalis

Arsenic is confirmed as one of the most persistent and threatening environmental contaminants to the integrity of aquatic ecosystems, frequently originating from industrial discharges related to microelectronics, textiles, and glass production. In order to gain deeper insights into toxicity pathways in macroinvertebrates, this study analyzed the biological responses of the freshwater gastropod Lymnaea stagnalis, an established bioindicator model. Adult specimens were subjected to a 7-day exposure to arsenic concentrations ecologically representative of contaminated sites.

The investigation focused on the digestive gland, which represents the primary organ involved in metabolic detoxification processes. The results highlighted severe structural and histological damage, characterized by tissue disorganization, intense cytoplasmic vacuolization, and marked inflammatory infiltration phenomena. At the biochemical level, the sub-lethal exposure triggered a massive production of reactive oxygen species (ROS) in the target tissues, providing clear evidence of severe oxidative stress. This altered redox status promoted a significant up-regulation of the molecular chaperone protein HSP70, confirming the activation of cellular defense and protein protection systems.

Furthermore, the concomitant modulation of key apoptotic biomarkers suggested that arsenic exposure can successfully trigger the early stages of programmed cell death pathways. Overall, this research elucidates the complex molecular networks and tissue alterations underlying metalloid toxicity in freshwater invertebrates. The findings reaffirm the high sensitivity and effectiveness of L. stagnalis as an ideal biological sentinel for environmental risk assessment and water quality monitoring programs.