University of Maryland (UMD) researchers have found evidence that a common, inexpensive, and safe antioxidant chemical called methylene blue could slow the aging of human skin, based on tests in cultured human skin cells and simulated skin tissue.

"The effects we are seeing are not temporary. Methylene blue appears to make fundamental, long-term changes to skin cells," said Kan Cao, senior author on the study and an associate professor of cell biology and molecular genetics at UMD.

The researchers tested methylene blue for four weeks in skin cells from healthy middle-aged donors, as well as those diagnosed with progeria — a rare genetic disease that mimics the normal aging process at an accelerated rate. The researchers also tested three other known antioxidants: N-Acetyl-L-Cysteine (NAC), MitoQ and MitoTEMPO (mTEM).

In these experiments, methylene blue outperformed the other three antioxidants, improving several age-related symptoms in cells from both healthy donors and progeria patients. The skin cells (fibroblasts, the cells that produce the structural protein collagen) experienced a decrease in damaging molecules known as reactive oxygen species (ROS), a reduced rate of cell death, and an increase in the rate of cell division throughout the four-week treatment.

Next, Cao and her colleagues tested methylene blue in fibroblasts from older donors (>80 years old), again for a period of four weeks. At the end of the treatment, the cells from older donors had experienced a range of improvements, including decreased expression of two genes commonly used as indicators of cellular aging: senescence-associated beta-galactosidase and p16.