title: Light interference as a possible stressor altering HSP70 and its gene expression levels in brain and hepatic tissues of golden spiny mice.
abstract: Light at night and light interference (LI) disrupt the natural light:dark cycle, causing alterations at physiological and molecular levels, partly by suppressing melatonin (MLT) secretion at night. Heat shock proteins (HSPs) can be activated in response to environmental changes. We assessed changes in gene expression and protein level of HSP70 in brain and hepatic tissues of golden spiny mice (Acomys russatus) acclimated to LI for two (SLI), seven (MLI) and 21 nights (LLI). The effect of MLT treatment on LI-mice was also assessed. HSP70 levels increased in brain and hepatic tissues after SLI, whereas after MLI and LLI, HSP70 decreased to control levels. Changes in HSP70 levels as a response to MLT occurred after SLI only in hepatic tissue. However, hsp70 expression following SLI increased in brain tissue, but not in hepatic tissue. MLT treatment and SLI caused a decrease in hsp70 levels in brain tissue and an increase in hsp70 in hepatic tissue. SLI acclimation elicited a stress response in A. russatus, as expressed by increased HSP70 levels and gene expression. Longer acclimation decreases protein and gene expression to their control levels. We conclude that for brain and hepatic tissues of A. russatus, LI is a short-term stressor. Our results also revealed that A. russatus can acclimate to LI, possibly because of its circadian system plasticity, which allows it to behave both as a nocturnal and as a diurnal rodent. To the best of our knowledge, this is the first study showing the effect of LI as a stressor at the cellular level, by activating HSP70.
authors.affiliation: The Israeli Center for Interdisciplinary Research in Chronobiology, Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa 31905, Israel. alilach@yahoo.com
authors.forename: Lilach
authors.initials: L
authors.lastname: Ashkenazi
authors.forename: Abraham
authors.initials: A
authors.lastname: Haim
mesh_terms: D000064:Acclimatization / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D002940:Circadian Rhythm / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D008027:Light; D008099:Liver / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D008297:Male; D008550:Melatonin / Q000494:pharmacology; D051379:Mice; D009115:Muridae / Q000235:genetics*; D017440:Photoperiod; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects
chemical_list: D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger; D008550:Melatonin