In MS patients the protective layer around nerve cells in the brain, known as myelin, is broken down.
Scientists have discovered that immune cells, known as macrophages, help trigger the regeneration of myelin.
The researchers hope their work could eventually lead to the development of new drugs.
The sheath around nerves cells, made of myelin, is destroyed in MS, leaving the nerves struggling to pass on messages.
This leads to problems with mobility, balance and vision. There is no cure but current treatments concentrate on limiting the damage to myelin.
Now the team at Edinburgh University has found that the immune cells, known as macrophages, can release a compound called activin-A, which activates production of more myelin.
Dr Veronique Miron, from the Medical Research Council Centre for Regenerative Medicine at the university, said: “In multiple sclerosis patients, the protective layer surrounding nerve fibres is stripped away and the nerves are exposed and damaged.
“Approved therapies for multiple sclerosis work by reducing the initial myelin injury – they do not promote myelin regeneration.
“This study could help find new drug targets to enhance myelin regeneration and help to restore lost function in patients with multiple sclerosis.”
The study, which looked at myelin regeneration in human tissue samples and in mice, was funded by the MS Society, the Wellcome Trust and the Multiple Sclerosis Society of Canada.
The findings are published in Nature Neuroscience.
Scientists now plan to start further research to look at how activin-A works and whether its effects can be enhanced.
Dr Susan Kohlhaas, head of biomedical research at the MS Society, said: “We urgently need therapies that can help slow the progression of MS and so we’re delighted researchers have identified a new, potential way to repair damage to myelin.
“We look forward to seeing this research develop further.”