Washington: A compound in dark chocolate may protect the brain after a stroke by increasing cellular signals already known to shield nerve cells from damage, Johns Hopkins researchers have discovered.
Ninety minutes after feeding mice a single modest dose of epicatechin, a compound found naturally in dark chocolate, the scientists induced an ischemic stroke by essentially cutting off blood supply to the animals`` brains.
They found that the animals that had preventively ingested the epicatechin suffered significantly less brain damage than the ones that had not been given the compound.
While most treatments against stroke in humans have to be given within a two- to three-hour time window to be effective, epicatechin appeared to limit further neuronal damage when given to mice 3.5 hours after a stroke. Given six hours after a stroke, however, the compound offered no protection to brain cells.
Sylvain Doré, Ph.D., associate professor of anesthesiology and critical care medicine and pharmacology and molecular sciences at the Johns Hopkins University School of Medicine, says his study suggests that epicatechin stimulates two previously well-established pathways known to shield nerve cells in the brain from damage.
When the stroke hits, the brain is ready to protect itself because these pathways — Nrf2 and heme oxygenase 1 — are activated. In mice that selectively lacked activity in those pathways, the study found, epicatechin had no significant protective effect and their brain cells died after a stroke.
The study appears online in the Journal of Cerebral Blood Flow and Metabolism.