Scientists have discovered a new mechanism behind the staying power of tattoos after a test involving inking laboratory mice. Even though your skin cells are constantly being replaced, the ink manages to persist. The science behind this involves immune cells known as macrophages. It is the macrophages that help the ink designs to last from generation to generation of skin cells. The research comes from a group of French researchers.
If this is the case, this would disprove former theories related to how and why tattoo ink manages to last in connective tissue or in the long-lasting macrophages. Sandrine Henri, an Immunologist at the Immunology Center of Marseille-Luminy in France and her colleagues tattooed mice tails with green ink in order to witness how waste-disposing macrophages might be involved in tattoo ink's persistence in the skin.
<blockquote>“Macrophages will scavenge everything. That’s their job,” Henri says. “If they could do their job properly, tattoo ink would be removed rapidly.”</blockquote>
The experiment was written up on March 6 in the Journal of Experimental Medicine. The research suggests that macrophages absorbed the ink but did not digest and dispose of it. The cells absorbed the ink until researchers killed the cells, but around 90 days later, new macrophages appeared which would reabsorb the ink. It was this "capture-release-recapture" cycle that was fundamental to what preserves the tattoo under the skin.
Desmond Tobin, a dermatology expert at the University of Bradford in the United Kingdom, was not involved in the study but offered his professional opinion that this mouse study doesn't necessarily settle the science of how and why tattoos persist in human skin. Macrophages may live long in humans than in mice, so the persistence of those cells may be responsible for preserving tattoos in human skin. This science, if corroborated by future studies, could help improve the process of tattoo removal. Laser treatment and a process of removing macrophages would possibly be helpful at removing the tattoo.
Check out The Goldwater documentary below to see some of the Goldwater gang get tattoos in the traditional Kalinga tradition using a pomelo thorn, bamboo and charcoal ink:
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