Skip Navigation



ToxSci Advance Access published online on November 4, 2003
Toxicological Sciences, doi:10.1093/toxsci/kfh015
Toxicological Sciences © Society of Toxicology 2003; all rights reserved
This Article
Right arrow Advance Access manuscript (PDF) Freely available
Right arrow All Versions of this Article:
77/2/299    most recent
kfh015v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Bolduc, J.-S.
Right arrow Articles by Jumarie, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bolduc, J.-S.
Right arrow Articles by Jumarie, C.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Received June 10, 2003; accepted October 6, 2003
© 2003 Society of Toxicology

In Vitro Toxicology and Alternative Testing

Cadmium-Induced Mitochondrial Membrane Potential Dissipation Does Not Necessarily Require Cytosolic Oxydative Stress: Studies Using Rhodamine-123 Fluorescence Unquenching

J.-S. Bolduc 1, F. Denizeau 1, and C. Jumarie 2*

1 Département de Chimie, Centre TOXEN, Université du Québec à Montréal, C.P. 8888, Succ. centre-ville, Montréal, Québec, Canada H3C 3P8
2 Département des Sciences Biologiques, Centre TOXEN, Université du Québec à Montréal, C.P. 8888, Succ. centre-ville, Montréal, Québec, Canada H3C 3P8

* To whom correspondence should be addressed. E-mail: jumarie.catherine{at}uqam.ca.


  Abstract

The impact of cadmium on the cellular redox state and mitochondria membrane potential ({psi}m) has been studied by monitoring DCF, CMXRos and Rh-123 fluorescence in 5-day-old TC7 cells, a highly differentiated clone of the human intestinal Caco-2 cell line. Flow cytometry analyses using DCFH oxidation to DCF clearly revealed that a 30-min incubation to 50 µM Cd is sufficient to induce reactive oxygen species (ROS) formation; this effect was completely eliminated by the presence of 50 mM mannitol for the 30-min incubation period, but mannitol scavenged only partially ROS for the longer period of time studied. Imaging studies using fluorescence video microscopy revealed a parallel increase in DCF fluorescence in the nuclear and cytoplasmic regions as soon as Cd was added to the exposure medium. Flow cytometry analyses monitoring CMXRos fluorescence clearly showed that Cd also lead to {psi}m disruption but, contrary to what was observed for ROS formation, mannitol was completely inefficient in preventing this effect. Further investigation using fluorescence microscopy and Rh-123 fluorescence unquenching revealed that although mannitol did not protect against Cd-induced dissipation of {psi}m, it considerably delayed the process. We found that Rh-123 unquenching occurring during probe redistribution is a suitable tool to monitor the decrease of {psi}m. We conclude that Cd rapidly induces ROS formation, mainly hydroxyl radical species OH•, as well as the loss of {psi}m. However, {psi}m dissipation does not necessarily require cellular OH• and may occur in the absence of apparent oxidative injury.

Key Words: cadmium, CMXRos, Rhodamine-123, ROS, mitochondria membrane potential, intestinal Caco-2 cells .


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.