South Korean Research Team Confirms Movement to Lymph Nodes, Lungs, and Liver in Mice
Also Finds Twofold Increase in Inflammation and Aging Gene Activity
A Korean research team has found through animal experiments that nanoplastics can penetrate the skin and spread to major organs such as the lymph nodes, lungs, and liver.
On December 1, Dr. Kim Jinsu's research team at the Korea Institute of Radiological & Medical Sciences announced that, using radioactive isotope labeling technology, they have for the first time demonstrated in mice that nanoplastics can permeate the skin and spread throughout the body.
The team applied nanoplastics measuring 20 nanometers in size, labeled with radioactive iodine (I-205), to the skin of laboratory mice and tracked their movement throughout the body using single-photon emission computed tomography imaging. The results showed that the nanoplastics reached the axillary lymph nodes within 10 days.
In long-term exposure experiments, the nanoplastics that entered through the skin were found to move to the lymph nodes in the first week, the lungs in the third week, and the liver in the fourth week, indicating a stepwise pattern of spread. By the end of the fourth week, nanoplastics were also detected in the bloodstream, which the research team explained demonstrates that even localized skin exposure can lead to systemic circulation of nanoplastics via the blood.
In contrast, when only radioactive iodine was administered, it was not detected in the lymph nodes, confirming that it was the nanoplastics themselves that penetrated and moved within the body.
The researchers also observed changes resulting from repeated long-term exposure. After three months of repeated exposure to nanoplastics, the expression of 294 genes increased while 144 genes decreased, indicating changes in gene expression.
Notably, the expression of genes related to inflammation and aging increased more than twofold, and tissue analysis revealed a decrease in skin layer thickness, confirming that nanoplastics can induce skin aging and chronic inflammation, according to the research team.
Furthermore, even as these changes occurred, indicators of skin barrier function remained within normal ranges. The team added that this suggests nanomaterials can penetrate the body even when the skin barrier is intact.
The research team confirmed that nanoplastics can pass through the skin barrier, which has been considered a shield protecting the body from external harmful substances. They also emphasized that this is the first time the pathway by which nanoplastics penetrate the body through the skin and spread systemically has been identified.
Dr. Kim Jinsu stated, "We hope this research will enhance our understanding of the movement and biological effects of nanoplastics within the body, and contribute to creating a safer living environment by minimizing the potential risks of plastics to human health and the environment in the future."
The results of this study were published in the international journal Journal of Hazardous Materials on November 21.
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