Phototoxicity of the fluorescent membrane dyes PKH2 and PKH26 on the human hematopoietic KG1a progenitor cell line

Cytometry. 1999 Aug 1;36(4):312-8. doi: 10.1002/(sici)1097-0320(19990801)36:4<312::aid-cyto5>3.0.co;2-v.

Abstract

Background: The phototoxic effects of the well-known fluorescent membrane dyes PKH2 and PKH26 have been unknown, although their use in cell tracking experiments has increased dramatically. To eliminate the phototoxicity-induced alteration in cell function and morphology, it is essential to examine the suspicious phototoxicity of these dyes.

Methods: Chemical and phototoxic effects of PKH dyes on the human hematopoietic KG1a cell line were examined. To minimize phototoxicity in long-term cell tracking experiments lasting up to 18 h with a fluorescence microscope system, time-lapse monitoring with different time intervals and exposure times was introduced.

Results: There were no significant effects of the two PKH dyes on cell viability and growth when using dye concentrations up to 5 microM. However, when stained cells were exposed to excitation light, cell viability decreased dramatically, showing the phototoxicity of the PKH dyes. More than 60% of cells stained with 5 microM PKH26 died after 5 min of continuous light exposure. The phototoxic effect was more extensive in cells stained with higher concentrations of the dyes.

Conclusions: We present guidelines for the optimal use of these dyes by using a defined hardware configuration.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Division / drug effects
  • Cell Membrane / drug effects
  • Cell Survival / drug effects
  • Fluorescent Dyes / toxicity*
  • Hematopoietic Stem Cells / drug effects*
  • Humans
  • Light*
  • Microscopy, Fluorescence
  • Organic Chemicals*
  • Signal Processing, Computer-Assisted
  • Time Factors
  • Tumor Cells, Cultured

Substances

  • Fluorescent Dyes
  • Organic Chemicals
  • PKH 26
  • PKH2-GL