title: Local anesthetic lidocaine induces apoptosis in human corneal stromal cells in vitro.
abstract: OBJECTIVE
  To demonstrate the apoptosis-inducing effect of lidocaine on human corneal stromal (HCS) cells in vitro, and provide experimental basis for safety anesthetic usage in clinic of ophthalmology.
  
  
  METHODS
  In vitro cultured HCS cells were treated with lidocaine at different doses and times, and their morphology was monitored successively with inverted phase contrast microscopy. The membrane permeability of them was detected by acridine orange/ethidium bromide (AO/EB) double staining. The DNA fragmentation of them was examined by agarose gel electrophoresis, and their ultrastructure was observed by transmission electron microscopy (TEM), respectively.
  
  
  RESULTS
  Exposure to lidocaine at doses from 0.3125g/L to 20g/L induced morphological changes of HCS cells such as cytoplasmic vacuolation, cellular shrinkage, and turning round, and elevated membrane permeability of these cells in AO/EB staining. The change of morphology and membrane permeability was dose- and time-dependent, while lidocaine at dose below 0.15625g/L could not induce these changes. Furthermore, lidocaine induced DNA fragmentation and ultrastructural changes such as cytoplasmic vacuolation, structural disorganization, chromatin condensation, and apoptotic body appearance of the cells.
  
  
  CONCLUSIONS
  Lidocaine has significant cytotoxicity on human corneal stromal cells in vitro in a dose- and time-dependent manner by inducing apoptosis of these cells. The established experimental model and findings based on this model here help provide new insight into the apoptosis-inducing effect of local anesthetics in eye clinic.
authors.affiliation: Key Laboratory for Corneal Tissue Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: School of Medicine, Shanghai Jiaotong University, Shanghai 200025, China.
authors.forename: Yi-Han
authors.initials: YH
authors.lastname: Li
authors.affiliation: Key Laboratory for Corneal Tissue Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China.
authors.forename: Hao-Ze
authors.initials: HZ
authors.lastname: Yu
authors.affiliation: Key Laboratory for Corneal Tissue Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China.
authors.forename: Rui-Xin
authors.initials: RX
authors.lastname: Wang
authors.affiliation: Key Laboratory for Corneal Tissue Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China.
authors.forename: Ting-Jun
authors.initials: TJ
authors.lastname: Fan
keywords: DNA fragmentation; apoptosis-inducing effect; apoptotic body; human corneal stromal cell; lidocaine