A recent study showed that laboratory rats exposed to Beijing's highly polluted air gained weight and experienced cardio-respiratory and metabolic problems.
The study, published in the Journal of the Federation of American Societies for Experimental Biology, demonstrated that breathing Beijing’s highly polluted air led to metabolism changes that caused weight gain, as well as heart and respiratory dysfunction in rats.
“The purpose of understanding all the biological processes is to see whether we can find some clinical way to help people who unfortunately live in those highly-polluted areas," said Jim Zhang, professor of global and environmental health in the Nicholas School of the Environment and one of the senior authors of the paper.
Zhang explained that the study, which was funded by several agencies of the Chinese government, used two groups of pregnant rats—one group was placed in a chamber with polluted Beijing air, and the other was exposed to air that had been purified with a filter.
"After 19 days of pregnancy, the pregnant rats exposed to the polluted air were heavier compared to the rats living in the clean air chamber and showed increased tissue inflammation,” Zhang said.
He noted that after their birth, the offspring were placed together with their mothers in the same chamber. After eight weeks, the two groups were weighed, and data showed that the offspring exposed to polluted air were significantly heavier than those exposed to clean air,
Yongjie Wei, a researcher at the Chinese Research Academy of Environmental Sciences, explained that limited experimental data showing the casual relationship of exposure to pollution and the increase of susceptibility to diet-induced weight gain currently exists. However, the study is the first to confirm a link between air pollution and non-diet-induced weight increases with more solid data.
Wei said that the study used rats because of their genetic commonality with humans.
"Understanding rats can help us to understand our human beings,” he said.
Using lab animals can help eliminate the differences between different subjects and makes it easier to control factors like diet and consumption, he added.
Although the results confirm that air pollution causes weigh gain and inflammation in rats, Zhang explained that further studies are needed to determine whether humans have a similar response.
“Whether we can see pollution impairing human in terms of weight is a study way more difficult to do because there are other things that are hard to control in humans, like diets and physical exercise," he said. "I don’t want people to over-interpret the study’s result. It’s just one more factor to consider in terms of the obesity problem."
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Further research projects are underway to determine if pollution and a high-fat diet can increase the risk of allergic diseases and asthma, which Wei said he expects to publish this year.
In the future, Zhang noted researchers are interested in finding ways to help people living in highly-polluted areas.
"I have been thinking of finding some therapeutic intervention to deal with the pollution,” Zhang said.