Scientists have found that RNA production is behind the regenerative affects of laser skincare treatments.

Laser treatments are a widespread cosmetic procedure to make skin appear younger and healthier. The laser slightly damages the skin cells, forcing them to repair themselves. After the repair process, the skin looks younger, but until recently the mechanism to how this happens was not well understood.

To understand this process, researchers looked at hair follicle rejuvenation in mice. Unlike humans, mice can regenerate hair follicles after a deep wound. The damaged cells release self-noncoding double stranded RNA molecules (dsRNA), which start the regeneration process. RNA are biological molecules that carry the information coded in DNA molecules to the cell’s protein synthesis machinery. 

Scientists measured the dsRNA expression levels in human cells after laser treatment and found the expression levels were elevated. Genes coding for the production of retinoic acid also had elevated expression. The scientists then introduced dsRNA to human faces, without laser treatment, and confirmed that the produced retinoic acid concentration was ten times higher than the normal level.

A receptor called TLR3 binds to dsRNA in both humans and mice. When scientists prevented expression of TLR3 in mice, they could no longer regenerate damaged hair follicles. However, when retinoic acid was administered to them their regenerative properties were restored. This indicates that the damaged cells release dsRNA, which triggers the synthesis of retinoic acid by binding to the TLR3 receptor. The retinoic acid then initiates the regenerative pathway.

This research could enable the development of new therapies for skin damage.

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