With Inflammation, It's Better to Have a Cool
Head
By Rosalie
Marion Bliss August 21, 2007
An abnormal immune system can mistake body tissue for a foreign
invader and attack it, causing inflammation. Researchers are learning how
similar dynamics occur in the brain. Agricultural Research Service (ARS) scientists have found that blueberry
extracts helped quell the inflammation that was produced when the brain's
immune cells responded to oxidative stress, based on a cell-culture study.
Lead author, molecular biologist Francis Lau, and neuroscientist
James
Joseph conducted the study at the USDA's Jean Mayer Human Nutrition
Research Center on Aging at Tufts University in Boston, Mass. Joseph leads the
HNRCA's
Neuroscience
Laboratory. ARS is USDA's chief scientific research agency. The study was
published in the Journal of
Neuroscience Research.
Inflammation is thought to be stoked by the overactivation of the
brain's immune cells, called microglia. While seeking to protect and repair
injured brain tissue, microglia produce and send out chemical stress
signalssome of which are called cytokinesto other cells. Those
signals begin a cascade of reactions, including the activation of genes that
express proteins and other stress chemicals to help clear away cellular
debris.
Microglia can become chronically overactivated, for example, in
response to accumulation of brain plaques, which in turn is thought to trigger
inflammation.
Lau used a rodent microglial cell line as a model to study
toxin-induced microglial activation. He exposed groups of those test cells to
various levels of blueberry extracts. He then challenged the cells with
oxidative stress by exposing them to the toxin that triggers the secretion of
inflammatory chemicals.
Neuroinflammation has been linked to the expression of genes that
spew, among others, two inflammatory enzymes, iNOS and COX-2, and two
cytokines, IL-1β and TNF-α. Lau used a detection method to find and
measure the expression of genes that produced iNOS and COX-2 in the
stress-induced cell cultures. He found that the blueberry treatment
significantly reduced that expression.
The blueberry extract also markedly lessened secretion of the two
inflammatory cytokines.
Read more
about this research in the August issue of Agricultural Research
magazine.