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One flash of light

Artificial light at night disrupts cell division

Issued on 13 April 2010

A new study from the University of Haifa and University of Leicester has found that just one "pulse" of artificial light at night disrupts the circadian mode of cell division - one of the body's mechanisms that is damaged in the development of cancer.

Just one "pulse" of artificial light at night disrupts circadian cell division, reveals a new study carried out by Dr. Rachel Ben-Shlomo of the University of Haifa-Oranim Department of Environmental and Evolutionary Biology along with Prof. Charalambos P. Kyriacou of the University of Leicester. "Damage to cell division is characteristic of cancer, and it is therefore important to understand the causes of this damage," notes Dr. Ben-Shlomo. The study has been published in the journal Cancer Genetics and Cytogenetics.

The current research was carried out by placing lab mice into an environment where they were exposed to light for 12 hours and dark for 12 hours. During the dark hours, one group of mice was given artificial light for one hour. Changes in the expression of genes in the rodents' brain cells were then examined.

Earlier studies that Dr. Ben-Shlomo carried out found that the cells' biological clock is affected, and in the present research she revealed that the mode of cell division is also harmed and that the transcription of a large number of genes is affected.

She states that it is important to note that those genes showing changes in their expression included genes that are connected to the formation of cancer as well as genes that assist in the fight against cancer. "What is certain is that the natural division is affected," Dr. Ben-Shlomo clarifies.

Professor Kyriacou, who is Professor of Behavioural Genetics at the University of Leicester added:

The work was done by Dr Rachel Ben-Shlomo in my laboratory at the University of Leicester as a study that examines the effects on brain gene expression of a one hour light pulse during the ‘night’ of a nocturnal rodent.

“The rational for doing this was to mimic human shift work schedules in which workers routinely are exposed to light during what would otherwise be their night. There have been many reports over the years of shift workers having health problems, including, in some cases, elevated levels of cancer.

“We observed that genes that are important in the control of the cell cycle, by which cells grow and divide, were affected by the light exposure. As these are the types of genes that have been implicated in tumour progression, we can see that chronic exposure to light during nightime, might not be such a good thing for health, and may underlie some of the illnesses that seem to afflict the shift-working population.

“Our current work continues to probe the relationship between health and the human 24 hour internal biorhythm.”

Note to Newsdesks

For more details contact Rachel Feldman via, Tel: +972-4-8288722

Or Professor Bambos Kyriacou on + 44 (0) 116 252 3430

Press office contacts:

Amir Gilat, Ph.D. Communication and Media Relations, University of Haifa Tel: +972-4-8240092/4 press@univ.haifa.ac.il

Ather Mirza, University of Leicester Press Office +44 116 252 3335 pressoffice@le.ac.uk