Air pollution makes it difficult to breathe and it can also increase the blood pressure and heart rate of the person. Those issues are well known. Now new research suggests breathing diesel fumes can trigger another toxic and dangerous change. It can inappropriately turn some genes on while turning some genes off.
A gene is a segment of our DNA that tells the cells of our body what to do and when to do it. Genes can be controlled by a chemical switch, also known as a methyl group. Methyl groups can cause a chemical reaction called methylation, thus affecting a component of DNA. This then tends to happen near a gene. If a methyl group is added, it can turn some gene off. The opposite tends to happen when you take a methyl group away or if you demethylate a gene. Either change can affect health.
That can be a good thing. The body can naturally produce methyl groups and it can allow it to turn off genes when their action is no longer needed. The factors outside the body, like air pollutants, may step in inappropriately and it may add methyl groups to DNA. They might remove methyl groups. These environmental changes can hijack the genes and they can change when or what they instruct the cells to do.
Harmful effects of air pollution
The study of methylation's role in gene action is named epigenetics. Epigenetics describes the changes that could happen outside of your DNA. These changes do not harm DNA. Instead, epigenetics may silence a gene or it can switch some gene on at the wrong time.
Researchers also stated that breathing diesel fumes of two hours can already have an epigenetic effect. It was done by the researchers at the University of British Columbia in Vancouver, Canada. They gathered 16 volunteers in an enclosed booth. The booth was about the same size as that of a small bathroom. They had the volunteer go inside the booth one by one and each of them remained there for at least two hours. They half breathed in clear air and the other half breathed air polluted with diesel fumes. The levels of that pollution were equal to the air along a highway in Beijing, China. The levels also might happen at rail yards, mines, busy ports, and industrial sites.
To check on the effects of pollution, the researchers looked at the blood of the volunteers. They compared the gathered samples collected before the experiment to those taken 6 and 30 hours after someone had sat in the exposure booth. The methyl groups changed at about 2,800 different points on the DNA of those who breathed in diesel fumes. Those changes affected 400 genes. No similar changes were seen among those breathing the clean air.
At some DNA locations, the exposure to diesel fumes added methyl groups. It reduced how many were present and that means that a switch that normally would turn off a gene was even more often flipped the other way. That could eventually lead to very high gene activity.
How these changes that are related to diesel might affect health is still not clear, according to Huawei Jiang, the author of the study. But the tests show that air pollution can alter the DNA. The data also showed that diseases like asthma might stem from prolonged episodes of methylation.
DNA changes in the body
Jiang stated that even short-term exposure can cause these types of changes. She hopes that other researches can identify the cumulative effects for someone who breathes in diesel fumes regularly. The findings of her team were published in the journal Particle and Fibre Toxicology.