Age-dependent effects of blue light exposure on lifespan, neurodegeneration, and mitochondrial physiology in Drosophila melanogaster Summary Blue light is a predominant component of light-emitting devices (LEDs), increasingly present in our environment. There is already accumulating evidence that blue light exposure causes damage to retinal cells in vitro and in vivo ; However, much less is known about the potential effects of blue light on non-retinal cells. That blue light can be harmful at the organismal level independently of the effect on the retina was recently demonstrated by findings that it reduces lifespan in worms and also in flies with genetically ablated retinas. Here, we investigated the effects of blue light exposure throughout the life of the fly and found that susceptibility to blue light stress is highly age- dependent . Blue light of the same intensity and duration reduced survival and increased neurodegeneration more significantly in old flies than in young flies. These differences appear to be caused, at least in part, by alterations in mitochondrial respiratory function. We report that blue light significantly reduces the activity of Complex II in the electron transport system and decreases the biochemical activity of succinate dehydrogenase in young and old flies. Furthermore, complex I and complex IV activities decline with age, as do ATP levels. Therefore, we propose that older flies are more sensitive to blue light because light-induced mitochondrial damage potentiates age-related deficiencies in energy metabolism that occur even in the dark. Taken together, our results show that the harmful effects of blue light at the organismal level are highly age-dependent and associated with reduced activity of specific components of energy production pathways in mitochondria. |
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The harmful effects of daily and lifetime exposure to blue light emanating from phones, computers and home accessories worsen as a person ages, new research from Oregon State University suggests.
The study, published in Nature Partner Journals Aging , involved Drosophila melanogaster, the common fruit fly, an important model organism because of the cellular and developmental mechanisms it shares with other animals and humans.
Jaga Giebultowicz, an OSU College of Science researcher who studies biological clocks, led a collaboration that examined the survival rate of flies kept in the dark and then moved at progressively older ages to an environment of constant blue light from diodes. light emitters, or LEDs.
The transitions from dark to light occurred at the ages of two, 20, 40 and 60 days, and the study involved the effect of blue light on the mitochondria of the flies’ cells.
Mitochondria act as a cell’s power plant, generating adenosine triphosphate or ATP, a source of chemical energy.
In previous research, Giebultowicz showed that prolonged exposure to blue light affected the longevity of flies, regardless of whether it shined in their eyes.
“The novel aspect of this new study shows that chronic exposure to blue light can affect energy production pathways even in cells that are not specialized for detecting light,” Giebultowicz said. “We determined that specific reactions in mitochondria were dramatically reduced by blue light, while other reactions were reduced with age, regardless of blue light. "You can think of it as blue light exposure adding insult to injury in aging flies."
Yujuan Song, Jun Yang and David Hendrix of the OSU College of Science, Matthew Robinson of the College of Public Health and Human Sciences, and Alexander Law and Doris Kretzschmar collaborated with Giebultowicz on the work, partially funded by the National Institutes of Health. from Oregon Health and Science University.
Scientists point out that natural light is crucial to a person’s circadian rhythm - the 24-hour cycle of physiological processes such as brain wave activity, hormone production and cell regeneration that are important factors in eating patterns. and I dream.
But there is evidence to suggest that increased exposure to artificial light is a risk factor for sleep and circadian disorders , Giebultowicz said. And with the predominant use of LED lighting and device displays, humans are subject to increasing amounts of light in the blue spectrum, as commonly used LEDs emit a high fraction of blue light.
“This technology, LED lighting, even in most developed countries, has not been used long enough to know its effects over the human lifespan,” he said. “There is growing concern that prolonged exposure to artificial light, especially blue-enriched LED light, may be harmful to human health. "While the full effects of lifelong blue light exposure in humans are not yet known , the accelerated aging observed in the short-lived model organism should alert us to the potential for cellular damage from this stressor." .
In the meantime, there are some things people can do to help themselves that don’t involve sitting for hours in the dark, researchers say. Glasses with amber lenses will filter out blue light and protect your retinas. And phones, laptops, and other devices can be set to block blue emissions.
“Our previous work demonstrated that lifelong daily exposure to blue light, but not other visible wavelengths, has detrimental effects on the brain, motor skills, and lifespan of the model organism,” Giebultowicz said. “We now report that the harmful effects of blue light in flies are highly age-dependent: the same duration of exposure to the same light intensity reduces lifespan and increases neurodegeneration more significantly in old flies. than in young women.”
In previous research, flies subjected to daily cycles of 12 hours in light and 12 hours in darkness had shorter lifespans compared to flies kept in total darkness or those kept in light at the lengths of filtered blue waves.
Flies exposed to blue light showed damage to retinal cells and brain neurons and had problems with locomotion: the flies’ ability to climb the walls of their enclosures, a common behavior, was diminished.
Some of the flies in the experiment were mutants that did not develop eyes, and even those eyeless flies showed disability, suggesting that the flies did not have to see light to be harmed by it.
| In summary , our results show that the damaging effects of BL at the organismal level are highly age-dependent and associated with reduced activity of specific components of energy-producing pathways in mitochondria. |
