WASHINGTON - Antioxidants, already widely promoted
as cancer-fighters, also may help protect the brain from chronic alcohol damage.
Chronic alcoholism damages parts of the brain used in learning and memory,
but giving rats an antioxidant protected them from the damage, according to
researchers working in the United States and Spain.
The findings are reported in Tuesday's online issue of Proceedings of the
National Academy of Science.
Antioxidants are chemicals that inhibit the oxidation of a substance to which
they are added. Oxidation can stress or damage cells.
The team, led by Dr. Daniel G. Herrera of Weill Medical College of Cornell
University, fed rats a liquid diet containing alcohol for six weeks.
They found a 66 percent decrease in the number of new cells in crucial parts
of the brain and an increase in cell death of more than 227 percent.
But in rats that also received injections of the antioxidant ebselen, the
damage to developing cells did not occur, the researchers said. Those rats had
the same brain characteristics as a group that received no alcohol.
Alcohol also kills liver cells, and the researchers knew that this can be
reduced with the use of antioxidants, Herrera said. They decided to see if the
same held for the brain.
The antioxidant ebselen was used because it is known to have protective
effects in the liver and digestive tract and has few side effects in humans.
Finding ways to improve mental function in people, particularly the elderly,
might increase positive results of alcohol treatment programs, Herrera said in a
statement.
Dr. Antonio Noronha, chief of the neuroscience and behavior branch of the
National Institute of Alcohol Abuse and Alcoholism, said this is the first study
to show the effects of antioxidants on chronic alcohol damage.
Noronha, who was not part of the research team, said similar findings have
been reported in studies at the University of North Carolina, but those focused
on binge drinking and used a different antioxidant.
The mechanism by which alcohol damages portions of the brain is still not
fully understood, he said. Oxidative stress seems to be part of it, and the
antioxidants appear to be protective.
Other reports in the same issue of Proceedings included:
_RU-486, the chemical used to induce abortions, may extend the life of brain
cells. Abdel Ghoumari, of the National Institute of Health and Medical Research
in France, and colleagues collected brain cells from mice in a laboratory
experiment. The cells normally undergo a programmed cell death in culture. But
when RU-486 was added to the culture, the life of the cells was
extended. The team said the finding may lead to future treatments for
brain-damaging diseases.
_A team of English and American researchers has engineered tobacco plants to
produce the human antibodies that are used to prevent rabies. The group, led by
Hilary Koprowski of Thomas Jefferson University in Philadelphia, developed a
genetic insert to the tobacco plants that codes them to produce the human
antibody. The antibody administered to prevent rabies now can be obtained from
horses and humans, but some people have adverse reactions to horse proteins, and
isolating the material from humans is expensive. The tobacco-produced antibodies
prevented development of rabies in hamsters exposed to the disease.
