title: Cytotoxic effects of ropivacaine, bupivacaine, and lidocaine on rotator cuff tenofibroblasts.
abstract: BACKGROUND
  Concern has recently arisen over the safety of local anesthetics used on human tissues.
  
  
  OBJECTIVE
  Aminoamide local anesthetics have cytotoxic effects on human rotator cuff tenofibroblasts.
  
  
  METHODS
  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 protein kinases (MAPKs) and caspase-3/7 were investigated.
  
  
  RESULTS
  The control and PBS groups showed no significant differences in cell viability (P > .999). In the local anesthetic study groups, cell viability decreased significantly with increases in anesthetic concentrations (P < .001) and exposure times (P < .001), with the exception of the lidocaine subgroups, where this effect was masked by the very high cytotoxicity of even low concentrations. Among the studied local anesthetic subgroups, 0.2% ropivacaine was the least toxic. The levels of intracellular ROS of each local anesthetic subgroup also increased significantly (P < .05). The studied local anesthetics showed increases in the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 as well as in levels of caspase-3/7 activity (P < .001).
  
  
  CONCLUSIONS
  The cytotoxicity of the anesthetics studied to tenofibroblasts is dependent on exposure time and concentration. Of the evaluated anesthetics, ropivacaine is the least toxic in the clinically used concentration. The studied anesthetics induce tenofibroblast cell death, mediated by the increased production of ROS, by the increased activation of ERK1/2, JNK, and p38 and by the activation of caspase-3/7.
  
  
  CONCLUSIONS
  This study identified the cytotoxic mechanisms of aminoamide local anesthetics acting on rotator cuff tenofibroblasts. The greatest margin of safety was found in lower anesthetic concentrations in general and more specifically in the use of ropivacaine.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Gyeongsang National University, Jinju, Korea.
authors.forename: Chang-Meen
authors.initials: CM
authors.lastname: Sung
authors.affiliation: Biomedical Research Institute, Gyeongsang National University Hospital, Jinju, Korea.
authors.forename: Young-Sool
authors.initials: YS
authors.lastname: Hah
authors.affiliation: Surgery of Foot & Ankle, Eulji Medical Center, Eulji College of Medicine, Eulji University, Seoul, Korea.
authors.forename: Jin-Su
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Musculoskeletal Research Center, Gyeongsang National University Hospital, Jinju, Korea.
authors.forename: Jeoung-Bin
authors.initials: JB
authors.lastname: Nam
authors.affiliation: Department of Convergence Medical Science, Gyeongsang National University, Jinju, Korea.
authors.forename: Ra Jeong
authors.initials: RJ
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Barun Hospital, Jinju, Korea.
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Gyeongsang National University, Jinju, Korea hbinpark@gnu.ac.kr.
authors.forename: Hyung Bin
authors.initials: HB
authors.lastname: Park
mesh_terms: D000577:Amides / Q000009:adverse effects; D000779:Anesthetics, Local / Q000009:adverse effects*; D002045:Bupivacaine / Q000009:adverse effects; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000187:drug effects*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008012:Lidocaine / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D000077212:Ropivacaine; D017006:Rotator Cuff / Q000166:cytology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D017382:Reactive Oxygen Species; D000077212:Ropivacaine; D008012:Lidocaine; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3; D053179:Caspase 7; D002045:Bupivacaine
keywords: aminoamide local anesthetics; cytotoxicity; rotator cuff; tenofibroblast