title: Supraphysiologic temperature enhances cytotoxic effects of bupivacaine on bovine articular chondrocytes in an in vitro study.
abstract: OBJECTIVE
  The purpose of this study was to determine the effects of temperature or 0.25% bupivacaine treatment in combination with supraphysiologic temperatures on chondrocyte viability.
  
  
  METHODS
  Bovine articular chondrocytes in suspension culture were treated with phosphate-buffered saline solution at 20°C, 37°C, 40°C, 42°C, 45°C, 47°C, and 50°C for 15, 30, and 60 minutes or with phosphate-buffered saline solution at 37°C, 45°C, and 50°C for 30 and 60 minutes followed by 0.25% bupivacaine at 20°C for 60 minutes. Chondrocyte viability was analyzed by flow cytometry with the LIVE/DEAD Viability/Cytotoxicity Kit (Molecular Probes, Eugene, OR). Annexin V and ethidium double staining determined whether apoptosis or necrosis occurred.
  
  
  RESULTS
  Temperatures from 20°C to 42°C did not cause chondrocyte death. Temperatures at or above 45°C caused significant chondrocyte death, particularly at 50°C for 60 minutes, compared with 37°C at 60 minutes (P < .01). When the chondrocytes were incubated at 50°C, subsequent exposure to bupivacaine significantly increased chondrocyte death compared with the saline solution-treated control group (P < .001). There were additive cytotoxic effects when bupivacaine was combined with supraphysiologic temperatures. It was also found that bupivacaine at supraphysiologic temperatures caused necrosis of articular chondrocytes.
  
  
  CONCLUSIONS
  Temperatures at or above 45°C caused significant chondrocyte death. Bupivacaine treatment in the presence of 45°C and 50°C temperatures significantly increased necrosis of bovine articular chondrocytes in this in vitro study.
  
  
  CONCLUSIONS
  Immediate intra-articular injection of bupivacaine after heat-generating procedures may cause damage to the cartilage because of the additive cytotoxic effects of bupivacaine and elevated temperature.
authors.affiliation: Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, Louisiana, USA.
authors.forename: R Nelson
authors.initials: RN
authors.lastname: Mead
authors.forename: Jessica
authors.initials: J
authors.lastname: Ryu
authors.forename: Sen
authors.initials: S
authors.lastname: Liu
authors.forename: Dongxia
authors.initials: D
authors.lastname: Ge
authors.forename: Justin
authors.initials: J
authors.lastname: Lucas
authors.forename: Felix H
authors.initials: FH
authors.lastname: Savoie
authors.forename: Zongbing
authors.initials: Z
authors.lastname: You
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002045:Bupivacaine / Q000008:administration & dosage / Q000009:adverse effects*; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects*; D005434:Flow Cytometry; D006358:Hot Temperature / Q000009:adverse effects*; D009336:Necrosis / Q000209:etiology
chemical_list: D000779:Anesthetics, Local; D002045:Bupivacaine