A widely used household chemical could provide a new way to treat skin disease, skin damage and even turn back the hands of time for ageing skin. At dilute concentrations, the chemical sodium hypochlorite, commonly used as bleach, can block a key regulator of inflammation in our bodies, researchers have found.
Dilute bleach baths have long been used to treat moderate to severe eczema, but while a paper in 2009 confirmed this clinically (Pediatrics, doi:10.1542/peds.2008-2217), scientists have never been able to work out why it works. ‘Because eczema is an inflammatory skin disease, we thought sodium hypochlorite was blocking this process and allowing the skin to heal better,’ says dermatologist Thomas Leung at Stanford University, US; the solution is so dilute that it is unlikely to work just by killing bacteria, he adds.
The group’s new study shows that bleach blocks NF-kB, a molecule known to play a crucial role in inflammation, ageing and in response to radiation (J. Clin. Invest., doi:10.1172/JCI70895).
Skin cells exposed to 0.005% bleach for one hour appeared to block the effects of NF-kB. Lab mice with radiation dermatitis given daily, 30-minute baths in bleach solutions experienced less severe skin damage and better healing and hair regrowth, compared with animals bathed in water.
As people and animals get older, NF-kB increases in our cells. ‘We took elderly mice and bathed them in a sodium hypochlorite solution and assessed them for any changes,’ says Leung. ‘We found that the skin of these mice appeared to look younger, had an increase in cell proliferation and some ageing genes reversed back to younger levels, which is exciting given it is such a simple treatment.’ The researchers also report that the skin thickened, though this effect diminished after the spa treatment ended.
The finding is ‘exciting,’ says systems biologist Alexander Hoffman at University of California, San Diego, US. ‘The fact that this commonly used chemical has such a strong anti-inflammatory activity blew my socks off. Why did I not know this? How was this missed previously?’ he asks. ‘This is exciting because NF-kB is inhibited. It may well inform treatment of disease, but eczema is not just about NF-kB. But it is definitely worth pursuing this clinically.’
The findings could also have implications for bed sores, foot ulcers and diabetic ulcers.