Histopathological changes in Melanopsis praemorsa exposed to imidacloprid and the protective effect of ascorbic acid

The widespread use of neonicotinoid pesticides, particularly imidacloprid, poses significant risks to aquatic ecosystems. This study investigates the histopathological effects of sublethal concentrations of imidacloprid (4.016 µg/L, 40.16 µg/L, and 80.32 µg/L) on the hepatopancreas and mantle tissues of Melanopsis praemorsa and evaluates the protective role of ascorbic acid. Snails were exposed to imidacloprid, with and without ascorbic acid, under laboratory conditions for 7, 14, and 21 days. Histopathological analysis revealed severe tissue damage, including vacuolation in digestive cells, hypertrophy of basophilic cells, lipid accumulation, and necrosis in the hepatopancreas. In the mantle, epithelial desquamation, muscle fiber atrophy, and increased lipid vacuoles were observed. However, ascorbic acid mitigated these effects, reducing the severity of tissue damage. The extent of histopathological alterations correlated with imidacloprid concentration and exposure duration. These findings suggest that M. praemorsa can serve as a bioindicator for pesticide pollution, and ascorbic acid may play a protective role against oxidative damage in aquatic organisms.