The nervous system’s own immune cells help protect the spinal cord from age-related damage, research suggests.
The findings may contribute to new knowledge about how certain neurological diseases arise.
Ageing affects the entire body, including the spinal cord, which transmits signals between the brain and the rest of the body.
Researchers at Karolinska Institutet investigated how ageing affects myelin, the protective layer which envelops nerve fibres in the brain and spinal cord.
By studying mice of different ages, they found that the myelin in a specific region of the spinal cord, the dorsal columns, gradually accumulates damage during ageing.
The researchers focused on microglia, the immune cells of the brain and spinal cord which help to keep the nervous system functioning properly.
Harald Lund, assistant professor at the Department of Physiology and Pharmacology at Karolinska Institutet, said: “It is known that microglia can affect the quality of myelin, so we wanted to understand how these cells respond to age-related myelin damage.”
In the ageing spinal cord, the researchers discovered that the microglia activated a signalling molecule called TGF-beta.
This appears to act as a brake, preventing the cells from becoming overactive and damaging nerve fibres.
To test the significance of this brake, the researchers switched off TGF-beta production in older mice.
Without the signal, the microglia began to attack the myelin, resulting in the mice developing clinical movement problems.
Robert Harris, professor at the Department of Clinical Neuroscience at Karolinska Institutet led the research together with Lund.
Harris said: “Damage has also been found in this particular region of the spinal cord in people with certain neurological diseases. Our results may help us understand why.”
The study was conducted in collaboration with researchers in China, the US and France.
