Effects of local anesthetics (lidocaine and dibucaine) on osteoblast and osteoclast activities: An in vitro study using goldfish scales

抄録

Local anesthetics such as lidocaine and dibucaine are widely used in surgical and therapeutic applications and are subsequently released into aquatic environments through human excretion and household wastewater. Lidocaine has been detected in rivers and in both influent and effluent of wastewater treatment plants at concentrations ranging from 7 ng/L to 9.133 µg/L, raising concerns about its potential effects on aquatic organisms. In this study, we used goldfish scales as a model system to investigate the effects of lidocaine and dibucaine on bone cells, as they contain osteoblasts (bone-forming cells) and osteoclasts (bone-resorbing cells), which are sensitive to environmental pollutants. Alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) activities, markers of osteoblast and osteoclast activity, respectively, were measured in goldfish scales after 6 h of incubation with lidocaine or dibucaine. The results showed that neither lidocaine nor dibucaine affected osteoblast or osteoclast activity in goldfish scales at environmentally relevant concentrations (10⁻¹¹ to 10⁻⁷ M; lidocaine: 2.34 ng/L–23.4 µg/L; dibucaine: 3.43 ng/L–34.3 µg/L). To evaluate the ratio of Measured Environmental Concentration (MEC) to Predicted No Effect Concentration (PNEC), additional experiments were conducted using higher concentrations of lidocaine (10⁻⁶ to 10⁻² M). TRAP activity significantly decreased following treatment with lidocaine at 10⁻² M. The MEC/PNEC ratio was 0.0038, which is below 1, suggesting that the environmental risk of lidocaine to fish bone metabolism is very low.