title: Comparison of toxicity effects of ropivacaine, bupivacaine, and lidocaine on rabbit intervertebral disc cells in vitro.
abstract: BACKGROUND
  It has been shown that bupivacaine, the most commonly used local anesthetic to relieve or control pain in interventional spine procedures, is cytotoxic to intervertebral disc (IVD) cells in vitro. However, some other common local anesthetics, such as ropivacaine and lidocaine, are also frequently used in the treatment of spine-related pain, and the potential effects of these agents remain unclear.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the effect of various local anesthetics on rabbit IVD cells in vitro and further compare the cytotoxicity of ropivacaine, bupivacaine, lidocaine, and saline solution control.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Rabbit annulus fibrosus (AF) and nucleus pulposus (NP) cells were isolated from Japanese white rabbits.
  
  
  METHODS
  Both AF and NP cells at the second generation maintained in monolayer were exposed to various concentrations of local anesthetics (eg, bupivacaine) or different durations of exposure and evaluated for cell viability by use of cell counting kit-8 (CCK-8). In addition, to compare the cytotoxicity of ropivacaine, bupivacaine, lidocaine, and saline solution control in commercial concentration, the viability was analyzed by flow cytometry after 60-minute exposure, and the morphologic changes were observed by the phase-contrast microscopy. Apoptosis and necrosis of IVD cells were confirmed by using fluorescence microscopy with double staining of Hoechst 33342 and propidium iodide.
  
  
  RESULTS
  Rabbit IVD cell death demonstrated a time and dose dependence in response to bupivacaine and lidocaine. However, ropivacaine only exerted a significant time-dependent effect on IVD cells. There was no significant difference in IVD viability after treatment with different doses of ropivacaine. In addition, the results showed that lidocaine was the most toxic of the three local anesthetics and that ropivacaine presented less cytotoxicity than lidocaine and bupivacaine. Fluorescence microscopy also confirmed that the short-term toxic effect of local anesthetics on both AF and NP cells was mainly caused by necrosis rather than apoptosis.
  
  
  CONCLUSIONS
  Results show that bupivacaine and lidocaine decrease cell viability in rabbit IVD cells in a dose- and time-dependent manner. All local anesthetics should be avoided if at all possible. Ropivacaine may be a choice if necessary, but it is also toxic. The increase in cell death is more related with cell necrosis rather than cell apoptosis. If these results can be corroborated in tissue explant models or animal studies, caution regarding diagnosing, treating, and controlling spine-related pain with local anesthetics is prompted.
authors: Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China.
authors: Xian-Yi
authors: XY
authors: Cai
authors: Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China.
authors: Li-Ming
authors: LM
authors: Xiong
authors: Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China. Electronic address: shuhua_yang@yeah.net.
authors: Shu-Hua
authors: SH
authors: Yang
authors: Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China.
authors: Zeng-Wu
authors: ZW
authors: Shao
authors: Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China.
authors: Mao
authors: M
authors: Xie
authors: Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China.
authors: Fei
authors: F
authors: Gao
authors: Department of Orthopaedic Surgery, The First People's Hospital of Jingmen, 448000, Jingmen, China.
authors: Fan
authors: F
authors: Ding
mesh_terms: D000577:Amides / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002045:Bupivacaine / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007403:Intervertebral Disc / Q000166:cytology* / Q000187:drug effects*; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D023421:Models, Animal; D011817:Rabbits; D000077212:Ropivacaine; D013997:Time Factors
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine; D008012:Lidocaine; D002045:Bupivacaine
keywords: Bupivacaine; Intervertebral disc; Lidocaine; Necrosis; Ropivacaine