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If you want your brain to function as well as possible up to old age, make sure you exercise a lot. Even if you dislike physical activity, and also if you are only happy behind a computer screen or reading a book, a sedentary lifestyle is disastrous for your brain. Italian researchers from the University of Milan come to this conclusion in an animal study, which has been published in Frontiers in Neurology.
Study
The researchers put a group of young C57BL / 6 mice for 14 days in a kind of wheelchair for rodents. The mice could do everything they normally did, except using their hind legs [Hind limb unloading; HU]. When the 2 weeks were over, the Italians studied the subventricular zone in the brains of the mice. The subventricular zone is a part of the brain where stem cells develop into full-fledged brain cells, that can take over the function of damaged and aged brain cells.
The researchers also studied the subventricular zone of mice that had full control over their hind legs [Control; CTR].
Results
In the studied tissues of the physically inactive mice, the stem cells were less vital than the stem cells of the animals in the control group.
In the stem cells of the inactive mice, the gene Cdk5rap1 was less active. That gene is involved in keeping the mitochondria, the 'power plants of the cell' , healthy.
"The discovery that Cdk5rap1 (which acts as methylthiotransferase in mitochondria RNA) was altered in its expression after motor deprivation is very intriguing in this context, and opens a new link between neurogenesis metabolism and cell regulation", write the Italians.
In the stem cells of the inactive mice, the researchers found fewer cells that produced the protein beta-tubulin-3. As only neurons and cells in the testis produce this protein, this means that fewer stem cells developed into new neurons in the inactive mice.
The researchers also found fewer stem cells with O4, a marker for oligodendrocytes. Oligodendrocytes are cells that provide neurons with nutrients. Physical inactivity also inhibits the production of this type of brain cell.
Conclusion
"Our study supports the notion that people who are unable to do load-bearing exercises not only lose muscle mass, but their body chemistry is altered at the cellular level and even their nervous system is adversely impacted", says first author Raffaella Adami in a press release.