The duration of sleep and wakefulness is regulated by circadian rhythms generated by the body’s internal clocks which are synchronized with the 24-hour period during which light changes occur. These internal clocks are responsible for regulating various biological processes and functions, such as the secretion of hormones, digestion of food or reproduction, and the aforementioned sleep-wake cycle, i.e. the appointed time to sleep or to perform various activities while awake.
The problem is that clocks can be easily disturbed by exposure to light at night, and shift workers experience this when they have to work night shifts. Various works have analyzed how this affects health and now a new study with female rats has shown that just four weeks of shift work patterns can alter their biological clock and reduce their fertility. are sufficient for
The research has just been presented at the 25th European Congress of Endocrinology and its results provide new clues for scientists to better understand how circadian disturbances affect female fertility, and ways to prevent future fertility problems in women. Can help develop strategy. Work non-standard hours.
Disrupting circadian rhythms lowers fertility
The ‘master biological clock’ is found in the suprachiasmatic nucleus, a small region of the brain called the hypothalamus, which is also the regulatory center for reproductive function by acting on the pituitary gland – linked to the lower part of the hypothalamus – which triggers ovulation. Regulates ovarian activity to promote. Several studies in rats and humans have shown that disrupting circadian rhythms have negative effects on female reproduction. However, why this happened could not be ascertained.
“Understanding the mechanisms by which circadian disruption impairs reproductive function may pave the way for mitigating some of the negative effects of shift work on women’s fertility”
Researchers from the Institute for Cellular and Integrative Neurosciences (INCI) and the University of Strasbourg, France, have previously shown that shift work patterns over several weeks reduce pregnancy rates in female rats. In the new study, researchers mimicked long-term shift work conditions in female mice by alternating light-dark cycles continuously, alternating light exposure for 10 hours over four weeks, and found that the massive release of a pituitary hormone called Is. Luteinizing hormone, which triggers ovulation, was removed, reducing fertility in these animals.
“The loss of fertility is caused by disturbances in the master circadian clock signaling to the hypothalamic reproductive circuitry,” said lead researcher Marine Simoneau. “Specifically, our research shows that four weeks of chronic exposure per shift disrupts the transmission of light information from the master biological clock to kisspeptin neurons, which is known to drive pre-ovulation or luteinizing hormone surges.” Is.”
The researchers’ next goal is to see whether additional internal clocks are disturbed after shift-work-like patterns change. “Circadian rhythms require not only the correct functioning of biological clock patterns, but also the synchronized activity of several secondary clocks found in other areas of the brain and peripheral organs, including the reproductive organs,” explained Ms. Simonenko. “Understanding the precise mechanisms by which circadian disruption alters reproductive function is important, as it may pave the way for potential preventive and therapeutic interventions to reduce some of the negative effects of shift work on women’s fertility. “