Immunotoxic effects of triclosan in the clam Ruditapes philippinarum

The effects of Triclosan (TCS) on the immune parameters of the clam Ruditapes philippinarum were investigated after a 7-day exposure to sublethal TCS concentrations (300, 600, and 900 ng l(-1)). Hemocytes from controls and exposed clams were collected, and the effects of TCS on total hemocyte count (THC), hemocyte diameter and volume, uptake of the vital dye Neutral Red (an indicator of pinocytosis), lysozyme activity, and proliferation were evaluated. The cytotoxicity, which was evaluated using the lactate dehydrogenase assay, and the capability of TCS to induce DNA fragmentation, which indicated apoptosis, were also investigated. The exposure of clams to all tested TCS concentrations significantly decreased THC, whereas the highest tested TCS concentration significantly reduced the diameter and volume of hemocytes. TCS negatively affected pinocytosis and the proliferation of hemocytes, but it did not alter hemocyte lysozyme activity. TCS exerted cytotoxic effects and induced DNA fragmentation in hemocytes of R. philippinarum. Overall, these results suggest a relationship between TCS exposure and changes in the measured immune parameters and indicate immunosuppression in TCS-treated clams.