. Earth Science News .

Air pollution linked to learning and memory problems and depression
by Staff Writers
Columbus OH (SPX) Jul 12, 2011

illustration only

Long-term exposure to air pollution can lead to physical changes in the brain, as well as learning and memory problems and even depression, new research in mice suggests.

While other studies have shown the damaging effects of polluted air on the heart and lungs, this is one of the first long-term studies to show the negative impact on the brain, said Laura Fonken, lead author of the study and a doctoral student in neuroscience at Ohio State University.

"The results suggest prolonged exposure to polluted air can have visible, negative effects on the brain, which can lead to a variety of health problems," Fonken said.

"This could have important and troubling implications for people who live and work in polluted urban areas around the world."

The study appears online this week in the journal Molecular Psychiatry.

For this study, Fonken and colleagues in Ohio State's Department of Neuroscience collaborated with researchers in the university's Davis Heart and Lung Research Institute.

In previous studies in mice, the Davis research group - including Qinghua Sun, associate professor of environmental health sciences, and Sanjay Rajagopalan, professor of cardiovascular medicine - found that fine air particulate matter causes widespread inflammation in the body, and can be linked to high blood pressure, diabetes and obesity. This new study aimed to extend their research on air pollution to the brain.

"The more we learn about the health effects of prolonged exposure to air pollution, the more reasons there are to be concerned," said Randy Nelson, co-author of the study and professor of neuroscience and psychology at Ohio State.

"This study adds more evidence of pollution's negative effects on health."

In the new study, mice were exposed to either filtered air or polluted air for six hours a day, five days a week for 10 months - nearly half the lifespan of the mice.

The polluted air contained fine particulate matter, the kind of pollution created by cars, factories and natural dust. The fine particulates are tiny - about 2.5 micrometers in diameter, or about 1/30th of the average width of a human hair. These particles can reach deep areas of the lungs and other organs of the body.

The concentration of particulate matter that the mice were exposed to was equivalent to what people may be exposed to in some polluted urban areas, according to the researchers.

After 10 months of exposure to the polluted or filtered air, the researchers performed a variety of behavioral tests on the animals.

In a learning and memory test, mice were placed in the middle of a brightly lit arena and given two minutes to find an escape hole leading to a dark box where they feel more comfortable. They were given five days of training to locate the escape hole, but the mice who breathed the polluted air took longer to learn where the escape hole was located. The mice exposed to polluted air also were less likely to remember where the escape hole was when tested later.

In another experiment, mice exposed to the polluted air showed more depressive-like behaviors than did the mice that breathed the filtered air. The polluted-air mice showed signs of higher levels of anxiety-like behaviors in one test, but not in another.

But how does air pollution lead to these changes in learning, memory and mood? The researchers did tests on the hippocampal area of the mice brains to find the answers.

"We wanted to look carefully at the hippocampus because it is associated with learning, memory and depression," said Fonken, who, along with Nelson, are also members of Ohio State's Institute for Behavioral Medicine Research.

Results showed clear physical differences in the hippocampi of the mice who were exposed to polluted air compared to those who weren't.

The researchers looked specifically at branches that grow off of nerve cells (or neurons) called dendrites. The dendrites have small projections growing off them called spines, which transmit signals from one neuron to another.

Mice exposed to polluted air had fewer spines in parts of the hippocampus, shorter dendrites and overall reduced cell complexity.

"Previous research has shown that these types of changes are linked to decreased learning and memory abilities," said Nelson.

In other studies, several of the co-authors of this study from the Davis research center found that chronic exposure to polluted air leads to widespread inflammation in the body, which is linked to a variety of health problems in humans, including depression. This new study found evidence that this low-grade inflammation is evident in the hippocampus.

In mice that breathed the polluted air, chemical messengers that cause inflammation - called pro-inflammatory cytokines - were more active in the hippocampus than they were in mice who breathed the filtered air.

"The hippocampus is particularly sensitive to damage caused by inflammation," Fonken said.

"We suspect that the systemic inflammation caused by breathing polluted air is being communicated to the central nervous system."

Other co-authors, all from Ohio State, included Qinghua Sun, associate professor of environmental health sciences; Sanjay Rajagopalan, professor of cardiovascular medicine; Xiaohua Xu, in environmental health sciences; Zachary Weil, in neuroscience and psychology; and Guohua Chen, in the Davis Heart and Lung Research Institute.

Related Links
Ohio State University
The Air We Breathe at TerraDaily.com

Get Our Free Newsletters Via Email
Buy Advertising Editorial Enquiries

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

New EPA rule targets blowing emissions
Washington (UPI) Jul 8, 2011
The U.S. Environmental Protection Agency issued final regulations capping pollution from coal-fired power plants. The Cross-State Air Pollution Rule, aimed at cutting emissions that contribute to pollution problems in other states, requires coal companies in 27 states to slash emissions of sulfur dioxide and nitrogen dioxide by 73 percent and 54 percent, respectively, from 2005 levels b ... read more

International Experts Blend Space Technologies and Crowdsourcing to Enhance Disaster Management Tools

Cyprus anger mounts over 'criminal' munitions blast

Radioactive ash found in waste plants near Tokyo

Japan quake makes 2011 costliest year: Munich Re

Google eBooks reader to debut in US

EA buying PopCap Games for $750 million

Hynix, Toshiba to develop new memory device

1C adds Russian intrigue to action videogames

Overuse of C.Asia's Amu-Darya a threat to stability: UN

Save the fish and feed the people, says EU fisheries chief

Scientists discover that Hawai'i is not an evolutionary dead end for marine life

LG, Hitachi to set up water treatment plant

Antarctic suvey finds undersea volcanoes

Antarctic krill help to fertilize Southern Ocean with iron

Warming ocean layers will undermine polar ice sheets

Russia to claim Arctic border expansion

New study suggests severe deficits in UK honeybee numbers

Sweetpotato foundation seed tested in commercial operations

Cool-season grasses more profitable than warm-season grasses

Nestle to pay 1.4 bn francs for 60% of Hsu Fu Chi

Support for Japan PM at record-low 15 percent

Intense rains generate alerts in Central America

Floods kill at least 20 in Nigeria's largest city

Australian volcano eruptions overdue

South Sudans wild hope for the future

DR. Congo colonel accused of mass rape surrenders: military

S. Sudan resources raise investor hopes

Ivorian president names ex-rebel general as army head

Early embryos can correct genetic abnormalities during development

Surgeons implant first synthetic organ

Australia moves on head-covering laws

Clues to why 'they' all look alike

Memory Foam Mattress Review
Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2011 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement