Research Paper|Volume 1, Issue 10|pp 855—865

Circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in rats

Irina A. Vinogradova¹, Vladimir N. Anisimov², Andrey V. Bukalev¹, Anna V. Semenchenko², Mark A. Zabezhinski²

¹Petrozavodsk State University, pr. Lenina, 33, Petrozavodsk 185910, Russia
²Department of Carcinogenesis and Oncogerontology, N.N.Petrov Research Institute of Oncology, Pesochny-2, St.Petersburg 197748, Russia

Received: August 26, 2009Accepted: September 30, 2009Published: October 2, 2009

Copyright: © 2009 Vinogradova et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

We evaluated the effect of various light/dark regimens on the survival, life span and tumorigenesis in rats. Two hundred eight male and 203 females LIO rats were subdivided into 4 groups and kept at various light/dark regimens: standard 12:12 light/dark (LD); natural lighting of the North-West of Russia (NL); constant light (LL), and constant darkness (DD) since the age of 25 days until natural death. We found that exposure to NL and LL regimens accelerated development of metabolic syndrome and spontaneous tumorigenesis, shortened life span both in male and females rats as compared to the standard LD regimen. We conclude that circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in rats. This observation supports the conclusion of the International Agency Research on Cancer that shift-work that involves circadian disruption is probably carcinogenic to humans.