Histochemistry and Cell Biology

, Volume 127, Issue 3, pp 263–271

Enzyme-assisted photosensitization with rose Bengal acetate induces structural and functional alteration of mitochondria in HeLa cells

  • M. G. Bottone
  • C. Soldani
  • A. Fraschini
  • C. Alpini
  • A. C. Croce
  • G. Bottiroli
  • C. Pellicciari
Original Paper

DOI: 10.1007/s00418-006-0235-9

Cite this article as:
Bottone, M.G., Soldani, C., Fraschini, A. et al. Histochem Cell Biol (2007) 127: 263. doi:10.1007/s00418-006-0235-9

Abstract

Rose Bengal acetate (RB-Ac) can be used as a fluorogenic substrate for photosensitization of cells both in vivo and in vitro: once inside the cells, RB-Ac is converted into photoactive rose Bengal (RB) molecules which redistribute dynamically in the cytoplasm and, upon irradiation by visible green light, can damage organelles such as the endoplasmic reticulum, the Golgi apparatus, and the cytoskeleton. Recently, evidence has been provided that mitochondria may also be affected. The aims of the present study were to describe RB-induced photodamage of mitochondria in single HeLa cells and to define, on a quantitative basis, the effects of photosensitization on their morphofunctional features. HeLa cell cultures were exposed to 10−5 M RB-Ac for 60 min and then irradiated with a light emitting diode at 530 nm (total light dose, 1.6 J/cm2). After irradiation, the cells were transferred to a drug-free complete medium and allowed to grow for 24–72 h. Using conventional and confocal fluorescence microscopy, transmission electron microscopy, and flow cytometry, we demonstrate that, in photosensitized cells, mitochondria undergo structural and functional alterations which can lead cells to apoptosis. Interestingly, in our system some cells were able to survive 72 h post-treatment and to recover, exhibiting the same mitochondrial structure, distribution and inner membrane potential as those in untreated controls. Taking into account that the photoactive molecules redistribute dynamically inside the cell upon RB-Ac administration, it may be hypothesized that cells can be differently affected by irradiation, depending on the relative amount and organelle location of the photosensitizer.

Keywords

Rose bengal acetate Photodamage Mitochondria Fluorescence microscopy Electron microscopy Cytometry 

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • M. G. Bottone
    • 1
    • 2
  • C. Soldani
    • 1
  • A. Fraschini
    • 1
  • C. Alpini
    • 3
  • A. C. Croce
    • 2
  • G. Bottiroli
    • 2
  • C. Pellicciari
    • 1
  1. 1.Dipartimento di Biologia AnimaleUniversità di PaviaPaviaItaly
  2. 2.Sezione di Istochimica e CitometriaIGM-CNRPaviaItaly
  3. 3.Laboratorio di Analisi Biochimico-ClinicheIRCCS San MatteoPaviaItaly

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