New research on mice shows that continually inhaling dirty air could be bad not just for the lungs but could also damage the brain tissue.
In the study, eight male mice were exposed to polluted air, and eight controls were exposed to filtered air.
On examining the brain tissues of the 16 mice, the researchers found that the mice that inhaled dirty air had developed amyloid deposits, neurofibrillary tangles, and plaques, while those that had inhaled filtered air showed no such developments.
While the whole experiment lasted two years, the mice were exposed to dirty air six days a week, eight hours a day, for 24 weeks (six months).
The researchers used a number of different analytical techniques to examine different tissues.
The exposure system used in this study could filter the ambient PM2.5. The composition of filtered air is similar with the outdoor air from which PM2.5 has been filtered.
The brains of mice exposed to dirty air showed tangles and plaques as well as neurofibrillary inflammations. In addition, chemical analysis found concentration increase in ceramide and sulfatides.
Earlier studies have shown that ceramide is directly involved in the aggregation of amyloid beta and the progression of Alzheimer’s disease. Sulphated galactosyl ceramide, also known as sulphatides (ST), are found in abundance at the myelin sheath of brain cells.
- This hypothesis is supported by previous reports that have shown that the expression levels of sulphatides are associated with the physiological activity of the blood-brain barrier, and increased concentration of sulphatide has impact on myelin sheath at early stages of HIV-1 infection.