Tuesday, August 08, 2006

Delayed cell death

Brain injuries, traumatic, toxic, or ischemic (lack of blood flow due to stroke or aneurysm) cause immediate cell death that is unavoidable. A secondary wave of death occurs, however, when cells adjacent to the damaged site basically commit molecular hari-kari. This secondary die-off is called apoptosis which means 'fading away,' an unfortunate event occurring in healthy neurons exposed to inflmmation.

Researchers have found in animal experiments that estrogen "dramatically" protects against this delayed cell death in brain injury. Neurobiologists at the University of Kentucky began the investigation by removing the ovaries of 100 rats, plummeting the unsuspecting rodents into menopause.

They then gave half the rats low doses of estrogen. After one week, the rats were subjected to an 'experimental stroke' as the researchers cut off blood flow through a cerebral artery. While estrogen did not protect against the initial cell death that occurred within hours of the stroke, it did markedly reduce the secondary damage.

The scientists have identified the mechanism by which the hormone protects the brain. They hope to develop designer estrogens in the future that have purely protective actions without any detrimental effects on body tissues such as the breasts.

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