Tamoxifen is the most commonly used antiestrogen for the treatment of breast cancer. Several clinical trials demonstrate that tamoxifen reduces the risk of heart disease and osteoporosis. However, the mechanism by which tamoxifen causes cardioprotection is unclear. Because increased levels of tumor necrosis factor α (TNFα) in tissue and/or plasma have been observed in virtually all forms of cardiac injury, we investigated whether tamoxifen prevents cardiac injury in a murine model of acute TNFα challenge. Five- to six-week-old female mice were injected (ip) with tamoxifen at 0.25 mg/kg daily for 3 or 7 days before receiving an injection of TNFα. Ultrastructural examination of cardiac tissues revealed remarkable protection against TNFα-induced mitochondrial damage in tamoxifen pretreated mice. Tamoxifen treatment significantly improved the mitochondrial respiratory function and enhanced superoxide-scavenging activity of mitochondria. These findings reveal a novel mitochondria-mediated mechanism by which tamoxifen exerts its cardiac protection effect against acute TNFα-induced heart injury.
|Number of pages||8|
|Journal||Free Radical Biology and Medicine|
|State||Published - Apr 1 2006|
Bibliographical noteFunding Information:
The authors thank Tanya Riddle at the University of Kentucky and Jamie Swanlund at the Veterans Administration Hospital Madison, WI, for excellent technical assistance. This work was supported by NIH Grants CA80152 and CA94853. Luksana Chaiswing is partially supported by the Thailand Research Fund under the Golden Jubilee Program. This work was supported in part by resources and facilities of the Veterans Administration Hospital, Madison, WI.
- Cardiac injury
- Superoxide removal
- Tumor necrosis factor
ASJC Scopus subject areas
- Physiology (medical)