Magnetic Shielding Extended Life in a Fruit Fly Model of Parkinson’s
Every person who has ever lived has spent every second of life inside a magnetic field. Earth’s magnetic field points compass needles north and helps migrating birds find their way. Whether the cells of the creatures living beneath it need that field for anything has been a far murkier question.
A new study in fruit flies points to an answer, and it comes with a twist. When researchers at the University of Nottingham shielded flies from nearly all of Earth’s magnetic field, flies carrying a gene defect linked to inherited early-onset Parkinson’s disease lived longer. Healthy flies became better climbers, while the Parkinson’s-model flies climbed worse. Same change in environment, opposite results, depending on the underlying health of each fly.
Professor Lisa Chakrabarti, who led the study with doctoral researcher Jacob Reed at Nottingham’s School of Veterinary Medicine & Science, laid out the gap the team set out to fill. Earth’s magnetic field “passes through our bodies, our cells and every living organism on the planet, yet we know surprisingly little about whether and how this invisible force affects the way our cells work,” she said in a university statement.
Her team also sees a possible medical payoff. In the paper, published in the journal Aging, the authors propose that removing the magnetic field could someday serve as a non-invasive way to target mitochondria, the tiny energy producers inside cells, in diseases like Parkinson’s. That idea sits a long way from the clinic. Nothing in the study involved people, and some of the results cut in unexpected directions.
Shielding fruit flies from Earth’s magnetic field
Earth’s magnetic field ranges in strength from about 25 to 60 microteslas, a unit scientists use to measure magnetic force. To strip it away, the researchers placed flies inside a benchtop shield made of MuMetal, an alloy that blocks magnetic fields. Inside the box, the field measured roughly 5 nanoteslas, thousands of times weaker than the planet’s natural field. Comparison flies lived outside the shield under the same light, noise and temperature conditions.
Fruit flies are a longtime workhorse of brain-disease research, and the team worked with two kinds: ordinary healthy flies and flies lacking a working Pink1 gene. In people, faulty versions of Pink1 are associated with inherited, early-onset Parkinson’s. Its job is to help cells clear out worn-out mitochondria. Without it, damaged mitochondria pile up, and the flies develop problems that mirror the disease, including sluggish movement, loss of the brain cells that make dopamine, and shorter lives.
Only male flies were used, because the Pink1 mutation sits on the X chromosome. One group of flies went into the shield at 10 days old and another at 20 days old, and both stayed inside for the rest of the experiment. Each starting point came before Parkinson’s-like symptoms usually appear in the mutant flies, at around 30 days of age. Researchers tracked survival for 70 days, using 40 to 60 flies per group, and tested climbing ability every five days.
Longer lives, weaker climbing
Among the Parkinson’s-model flies, those moved into the shield at 20 days old survived better than unshielded flies, with about half the risk of dying at any given point during the study. In their summary, the authors put the lifespan gain for these flies at 20%. Flies shielded starting at 10 days old showed a smaller improvement, too small to rule out chance, which led the researchers to conclude that the timing of shielding matters.
Longer life did not come with better movement. In a standard fly fitness test, researchers tap a vial so the flies drop to the bottom, then count how many climb past a marked line within a set time. Shielded Parkinson’s-model flies did worse than their unshielded counterparts at every checkpoint from day 20 through day 40, on top of the movement problems the mutation already causes.
Healthy flies flipped that pattern. Shielded healthy flies out-climbed unshielded ones at days 20, 30 and 40. Their survival dipped somewhat inside the shield, and both the paper’s summary and the university’s press release describe a shorter lifespan for these flies. In the paper’s own statistical analysis, though, that drop was small enough that it could have been due to chance.
Earth’s magnetic field and the cell’s power plants
To understand the split, the team looked inside the flies’ mitochondria, which turn food and oxygen into usable energy. Mitochondria rely on a chain of protein machines that pass electrons along like a bucket brigade. One of those machines works as a kind of backup generator, a reserve the cell can lean on when it is under stress.
In healthy flies shielded from the magnetic field, that backup system ran harder than in unshielded flies. Parkinson’s-model flies showed a similar uptick, but it was too small to confirm with only four samples per group, each made from three ground-up flies.
Researchers also measured free radicals, unstable molecules that can damage cells in large amounts. For this, they used an unusual tool: quantum sensors built from nanodiamonds, tiny diamond particles with atom-sized flaws whose glow shifts, with the help of a chemical probe, when free radicals are present. Shielded flies showed higher free-radical levels, most clearly the Parkinson’s-model flies at rest. In those same flies, the jump in free radicals that normally comes when mitochondria shift into high gear was smaller under shielding. Because the test ran on samples of ground-up whole flies, it could not pin down exactly where the free radicals came from, though the authors consider them most likely tied to mitochondrial activity.
According to the authors, losing the magnetic field may act as a mild stress that pushes cells to lean on their backup energy system. In healthy flies, that extra demand could strain the mitochondria. In Parkinson’s-model flies, where the first machine in the energy chain is already known to work poorly, the backup could help fill the gap. Researchers present that explanation as a proposal, not a proven mechanism.
Source : https://studyfinds.com/earths-magnetic-hidden-role-aging/
