The researchers found that the hair follicles contain a record of the 24-hour circadian cycle that defines our sleep habits. The method could help patients with sleep disorders and assess health problems in night shift workers. – writes the portal Science Now.
Researchers thought that the circadian clock was only located in the brain. However, scientists discovered in the late 90s that circadian rhythm genes are expressed in tissues throughout the body. In a series of experiments with mice, researchers have linked these genes to changes in body weight and even loss of time after consuming marijuana. However, it was more difficult to study this phenomenon in humans. This is because gene analysis is based on invasive tests such as taking blood several times a day or cutting out a small piece of skin.
Makoto Akashi from Yamaguchi University in Japan and his colleagues looked for a simpler way to determine the activity of a gene that regulates the circadian cycle. They used hair torn from the scalp or beard. After RNA isolation from these cells, they found that the activity of the circadian rhythm gene increased when the volunteers were awake and active, and that it was activated first in those who got up unusually in the morning.
Then Akashi and his colleagues interrupted the sleep-wake rhythm of healthy people. They asked volunteers to go to bed later and later and illuminate them with intense light for 30 minutes after waking up. The experiment lasted for 3 weeks. By the end of these 3 weeks, when volunteers were waking up about 4 hours later than usual, home rhythm gene activity in their hair follicles also changed, but only by about 2,5 hours, the team at Proceedings of the National Academy of Sciences.
Akashi’s group saw a similar change in people working at night. The team examined the hair follicles of volunteers who worked the 6st shift from 15am to 15pm the first week, the XNUMXnd shift from XNUMXpm to midnight, and back to the XNUMXst shift the XNUMXrd week.
The activity of the gene was 5 hours delayed in relation to the lifestyle of working shifts, which indicates that 3 weeks is not enough for the body clock to adapt to the new patterns. Tracing the circadian rhythm genes in the hair follicles is helping scientists apply better monitoring of patients with sleep disorders and other circadian rhythm disorders, says molecular biologist Ueli Schibler of the University of Geneva in Switzerland. Because the genes that control everything from organ function to eating rhythm, the delay seen in shift workers could explain some of their important health problems. (PAP)