Exposure to air pollution over a long period of time can physically change the brain and lead to learning and memory problems as well as depression, according to a study.
The study, led by Ohio State University's Department of Neuroscience, set out to look at air pollution's impact on the brain. Most studies have looked at pollution and the effect on the heart and lungs. The study was published in the journal Molecular Psychiatry.
According to an Ohio State statement, the study subjected mice to filtered and polluted air for six hours a day, five days a week for 10 months. That time span equated to half the lifespan for the mice.
The polluted air had fine particulate matter, similar to what cars, factories and natural dust produce. The particulates were 2.5 micrometers in diameter. The particles replicate what a human would be exposed to in polluted urban areas. Once the 10 months of exposure was complete, Ohio State researchers conducted behavioral tests.
For learning and memory, mice were put in a brightly lit area and given two minutes to find an escape hole leading to a dark box. The mice were given 5 days of training to find the escape hole. Pollution exposed mice took longer to learn where the escape hole was located and were less likely to remember the location in later tests.
Additional tests showed that mice exposed to polluted air had more depressive behaviors.
- Researchers also tested mice brains to see how air pollution affected the brain. Specifically, the hippocampus was examined. Among the findings:
- Mice exposed to pollution had physical differences in their hippocampi.
- Pollution exposed mice had fewer dendrite spines---branches growing from nerve cells---than counterparts with regular air.
- Mice exposed to pollution also had widespread inflammation, which can lead to a bevy of health problems including depression.