Cytotoxic Effects of Ropivacaine, Bupivacaine, and Lidocaine on Rotator Cuff Tenofibroblasts

Background:Concern has recently arisen over the safety of local anesthetics used on human tissues.Hypothesis:Aminoamide local anesthetics have cytotoxic effects on human rotator cuff tenofibroblasts.Study Design:Controlled laboratory study.Methods:Cultured human rotator cuff tenofibroblasts were divided into control, phosphate buffered saline (PBS), and local anesthetic study groups; the PBS study group was further subdivided by pH level (pH 7.4, 6.0, and 4.4). The 6 local anesthetic subgroups (0.2% and 0.75% ropivacaine, 0.25% and 0.5% bupivacaine, and 1% and 2% lidocaine) were also studied at 10% dilutions of their original concentrations. Exposure times were 5, 10, 20, 40, or 60 minutes for the higher concentrations and 2, 6, 12, 24, 48, or 72 hours for the lower concentrations. Cell viability was evaluated through live, apoptotic, and necrotic cell rates using the annexin V–propidium iodide double-staining method. Intracellular reactive oxygen species (ROS) and the activity of mitogen-activated protei...