Research: The harm caused by blue light exposure increases with age

Drosophila melanogaster is a useful model organism because it shares cellular and developmental mechanisms with humans and other animals.

A team led by Jaga Giebultowicz, a scientist at the OSU Institute of Science specializing in circadian rhythms, studied the survival rate of flies maintained in darkness and then transferred to a continuous blue light environment provided by Light-emitting diode (LED) lamps as their age increased.

The transition from darkness to light occurs at 2 days, 20 days, 40 days, and 60 days; the study focuses on the effect of blue light on the mitochondria of fly cells.

Mitochondria act as the power plants of cells, producing adenosine triphosphate (ATP)--a source of chemical energy.

In early studies, Giebultowicz pointed out that long-term exposure to blue light affects the lifespan of flies, regardless of whether the blue light reaches their eyes.

Giebultowicz stated: "The novelty of this new study lies in demonstrating that long-term exposure to blue light damages the pathways for energy production, even in cells that do not specifically perceive light. We identified that specific reactions in mitochondria are sharply reduced by blue light, while other reactions decline with age, unrelated to blue light. You can view it as blue light adding insult to injury in aging flies."

It is reported that this study was conducted by Yujuan Song, Jun Yang, David Hendrix, and Matthew Robinson from the OSU College of Science, along with Alexander Law and Doris Kretzschmar from Oregon Health & Science University, in collaboration with Giebultowicz. This research received partial funding from the U.S. National Institutes of Health.

Natural light is very important for a person's circadian rhythm, which is a 24-hour physiological cycle that affects a person's eating and sleeping habits—including hormone secretion, brain wave activity, and cell regeneration.

However, according to Giebultowicz, studies suggest that increased exposure to artificial light may be a risk factor for sleep and circadian rhythm disorders. Due to the widespread use of LED lights and device screens, humans are also exposed to increasing amounts of blue light, as these devices emit high levels of blue light.

She said: "This technology, LED lighting, has not been used long enough in most developed countries to understand its impact on human lifespan. There is growing concern that prolonged exposure to artificial light, especially LED light rich in blue light, may cause harm to human health. Although the full impact of blue light exposure over a lifetime remains unclear in humans, the accelerated aging observed in short-lived model organisms should alert us to the potential damage this stressor can cause to cells."

研究人员还表示，与此同时，人们可以做一些事情来帮助自己，而不需要在黑暗中坐几个小时。带琥珀色镜片的眼镜将过滤掉蓝光并保护视网膜，而手机、笔记本电脑和其他设备可以被设置为阻止蓝光发射。

"Our previous work has shown that lifelong exposure to blue light, as opposed to other visible wavelengths, has a destructive impact on the brain, motor function, and lifespan of model organisms. We now report that the detrimental effects of blue light on flies are strongly age-dependent: under the same light intensity and exposure duration, older flies exhibit shortened lifespans and increased neurodegeneration compared to younger flies," said Giebultowicz.

In early studies, flies kept on a 12-hour light/dark cycle had shorter lifespans compared to those kept in complete darkness or under filtered blue-wavelength light.

Flies exposed to blue light show damage to their retinal cells and brain neurons, along with impaired motor abilities--their ability to climb walls (a common behavior) is also weakened.

Since some flies in the experiment were mutants that did not grow eyes, and even those without eyes showed damage, this indicates that flies do not necessarily need to see light to be harmed.

Source: cnBeta.COM