title: Imaging of reactive oxygen species burst from mitochondria using laser scanning confocal microscopy.
abstract: OBJECTIVE
  Although several methods have been used to detect the intracellular reactive oxygen species (ROS) generation, it is still difficult to determine where ROS generate from. This study aimed to demonstrate whether ROS generate from mitochondria during oxidative stress induced mitochondria damage in cardiac H9c2 cells by laser scanning confocal microscopy (LSCM).
  
  
  METHODS
  Cardiac H9c2 cells were exposed to H2 O2 (1200μM) to induce mitochondrial oxidant damage. Mitochondrial membrane potential (ΔΨm) was measured by staining cells with tetramethylrhodamine ethyl ester (TMRE); ROS generation was measured by staining cells with dichlorodihydrofluorescein diacetate (H2 DCFDA).
  
  
  RESULTS
  A rapid/transient ROS burst from mitochondria was induced in cardiac cells treated with H2 O2 compared with the control group, suggesting that mitochondria are the main source of ROS induced by oxidative stress in H9c2 cells. Meanwhile, the TMRE fluorescence intensity of mitochondria which had produced a great deal of ROS decreased significantly, indicating that the burst of ROS induces the loss of ΔΨm. In addition, the structure of mitochondria was damaged seriously after ROS burst. However, we also demonstrated that the TMRE fluorescence intensity might be affected by H2 DCFDA.
  
  
  CONCLUSIONS
  Mitochondria are the main source of ROS induced by oxidative stress in H9c2 cells and these findings provide a new method to observe whether ROS generate from mitochondria by LSCM. However, these observations also suggested that it is inaccurate to test the fluorescence intensities of cells stained with two or more different fluorescent dyes which should be paid more attention to.
authors.affiliation: Heart Institute, Medical Experimental Research Center, Hebei United University, Tangshan, Hebei, 063000, China.
authors.forename: Jingman
authors.initials: J
authors.lastname: Xu
authors.forename: Zhimei
authors.initials: Z
authors.lastname: Hao
authors.forename: Xiangbo
authors.initials: X
authors.lastname: Gou
authors.forename: Wei
authors.initials: W
authors.lastname: Tian
authors.forename: Yulan
authors.initials: Y
authors.lastname: Jin
authors.forename: Shuxia
authors.initials: S
authors.lastname: Cui
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.forename: Yujie
authors.initials: Y
authors.lastname: Sun
authors.forename: Ya
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhelong
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000818:Animals; D002460:Cell Line; D006861:Hydrogen Peroxide / Q000633:toxicity; D018613:Microscopy, Confocal / Q000379:methods*; D008928:Mitochondria / Q000737:chemistry* / Q000502:physiology*; D018384:Oxidative Stress; D051381:Rats; D017382:Reactive Oxygen Species / Q000032:analysis*; D016897:Respiratory Burst
chemical_list: D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide