A food supplement added to water may offer hope for millions of osteoarthritis patients, a study suggests.
Belgian researchers found mice with the agonising condition given N-acetyl cysteine (NAC) have significantly less cartilage damage.
The team at the Catholic University of Leuven revealed the damage in those mice was similar to that seen in rodents without osteoarthritis.
Eight million people in the UK and 54 million in the US have osteoarthritis – when the cartilage becomes thin.
Medications have been designed only to help relieve pain for sufferers but these have side effects, including stomach ulcers.
The new breakthrough, published in Science Translational Medicine, could add another weapon to the arsenal of patients in agony.
NAC is often dished out by doctors to treat paracetamol poisoning, chest pain and to combat allergic reactions to an epilepsy drug.
But it is also sold in food retailers, such as Holland & Barrett for £8.99, as a supplement that many take for claims it can protect the liver.
Scientists remain baffled as to the exact molecular mechanisms behind the gradual wear and tear of cartilage.
But the new study found levels of a protein are lower in cartilage tissue samples from humans and mice with osteoarthritis.
Further experiments revealed ANP32A drives production of a natural enzyme which halts oxidative stress – a damaging bodily process.
NewScientist reports the finding suggests oxidative stress in cartilage cells could be a key cause of osteoarthritis.
Dr Frederique Cornelis and colleagues then bred mice unable to produce ANP32A. They quickly developed severe osteoarthritis.
However, treating them with NAC added to their drinking water healed their joints and reduced cartilage damage to that seen in healthy mice.
Professor Rik Lories, also involved in the latest study, was quick to point out that NAC may not help humans.
He told the online scientific news site that the supplement may not reach cartilage in sufficient amounts to restore damage.
The researchers now hope to find ways of boosting ANP32A, which, they say, could offer ‘better protection against oxidative stress’.
Osteoarthritis, the most common form of arthritis and mainly affects women, causes the distance between bones to shrink as cushioning cartilage is lost from joints.