Animal study shows fatigue from brain inflammation found to worsen with age
A procedure that induces fatigue in mice by activating the immune system has produced new insights into the underlying neural mechanisms that trigger fatigue, a common and often disabling symptom, according to research presented November 17 at Neuroscience 2014, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health.
“It’s important to have a method to induce fatigue in mice so that we can develop better clinical treatments,” said senior author Mary Harrington, PhD, of Smith College in Northampton, Mass. “With this new procedure, we can now identify the brain cells that generate fatigue in mice and are beginning to map the brain pathways by which inflammation in the brain leads to that fatigue.”
It’s estimated that more than one - third of the workforce in the United States has experienced fatigue lasting longer than two weeks, costing employers more than $100 billion every year. Chronic fatigue is also common in people with neurological disorders. Up to 40 percent of people with Parkinson’s disease and multiple sclerosis, for example, cite fatigue as being the most disabling symptom of their disease.
The procedure developed by Harrington and her colleagues uses the cytokine IL-1 to initiate fatigue in mice without other symptoms, thus allowing researchers to explore the brain pathways related specifically to fatigue. With the procedure, Harrington and her team have recently discovered that the fatigue associated with inflammation within the mouse brain gets worse with age and that it does not require, as was previously suspected, a reduction in the activity of orexin neurons, which play a big role in keeping the brain alert and awake.