Effect of Light at Night on oxidative stress markers in Golden spiny mice (Acomys russatus) liver

Influence of light supplement on duck sternal calcification from integrated analysis of metabolome and transcriptome

Calcification of bones is the critical process of bone development in birds, which is very important for sustaining the normal biological function of bones. Light is one of the vital factors affecting bone development, but whether light intensity affects bone calcification and the underlying mechanism is still unknown. In this study, we used duck sternum as a model to analyze the calcification process under different light regimes. In addition, the underlying mechanism was also illustrated by integrating metabolomics and transcriptome methods. The experiment lasted from 14 to 51 d of duck age. The control group (LP1) kept light intensity 2 lx during the whole experiment. The two light supplement groups (LP2, LP3) were given light with the intensity of 70 lx at different time (14-29 d for LP2, 14-43 d for LP3). Samples were collected at 52 d of duck age. Sternal calcification analysis showed no significant difference in proportion of area of cartilage matrix and trabecular bone in keel tissue among the 3 groups, but the degree of keel calcification in LP3 was higher than in the other 2 groups. Serum metabolomics showed 32 and 28 differentially accumulated metabolites (DAMs) in the 2 comparison groups, LP1 vs. LP3 and LP1 vs. LP2, respectively. Carboxylic acids and derivatives were the most abundant among the DAMs. Sternal transcriptome analysis showed 231 differentially expressed genes (DEGs), including 177 upregulated genes and 54 downregulated genes in group LP1 vs. LP3, and 22 DEGs in group LP1 vs. LP2. Protein-protein interaction (PPI) network analysis on DEGs between LP1 and LP3 showed that genes BTRC, GLI1, BMP4, and FOS were in the core position of the interaction network, and are also involved in bone development. KEGG pathway analysis of DAMs and DEGs showed that differences in Hedgehog signaling pathway, MAPK signaling pathway, apoptosis, energy metabolism, and amino acid metabolism following light treatment seem likely to have contributed to the observed difference in calcification of duck sternum.

HSP70 plays a role in the defense of acute and chronic heat stress in Mongolian gerbils (Meriones unguiculatus)

Mongolian gerbils (Meriones unguiculatus) show a wide thermal neutral zone (TNZ, 26.5-38.9 °C). Whether heat shock proteins (HSPs) are involved in thermal tolerance for gerbils has still been unknown. We investigated the effects of acute and chronic high temperature within and above TNZ on the expressions of HSP70 and HSP90 and oxidative status in Mongolian gerbils, to test the hypothesis that the gerbils need increase the expression in HSPs to defense the acute and chronic heat stress. In experiment I, 50 Mongolian gerbils were exposed to 23 °C, 27 °C, 37 °C, 40 °C and 43.5 °C for 80 min respectively, and then sacrificed 12 h after treatment. HSP70 expression in the liver increased at 40 °C compared to that at 23 °C, but did not change after 27 °C, 37 °C or 43.5 °C exposure. There were no differences in HSP90 expression, oxidative stress parameters such as malonaldehyde (MDA) and hydrogen peroxide (H₂O₂), or antioxidant parameters such as superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in the liver. HSP70 and HSP90 expression both in the heart and brain showed no differences among groups. In experiment II, another set of 30 gerbils were acclimated to 23 °C, 27 °C and 37 °C for 21 days, respectively. During chronic acclimation, HSP70 expression increased and H₂O₂ level decreased in the liver in 37 °C group compared to other two groups. Both H₂O₂ and SOD in the brain decreased in 37 °C group, but there were no differences in HSP70, MDA or T-AOC in the brain. These data indicate that Mongolian gerbils can maintain basal levels of HSPs after acute exposure to temperatures within the wide TNZ, but rely on increased HSP70 in the liver to protect from heat damage at temperatures above TNZ and during chronic heat acclimation. The increased HSP70 expression in the liver may contribute to keeping from heat damage in desert rodents.

Identifying, Examining, and Planning Areas Protected from Light Pollution. The Case Study of Planning the First National Dark Sky Park in Greece

Light pollution is a type of pollution that climaxes in cities and occurs increasingly away from them, due to the increase of artificial lighting and inappropriate lighting design (selection of luminaires, aiming, illuminance/luminance levels, and spectral characteristics). Increasingly, light pollution also affects the countryside due to local lighting but also distant lighting propagating from urban areas. This has a significant impact on ecosystems and astronomical observing sites. This work analyzes the main facts about light pollution (causes, impact, and solutions) and studies the methods, parameters, and special requirements for planning of light pollution protected areas. This dark sky park planning methodology is implemented as a case study in mount Parnon which has been selected due to its significance as a Natura 2000 protected area and because it is Greece’s most popular astronomical observing site. Mount Parnon is located close to two major cities as well as significant highways, however the site itself remains dark due to its sparse population. Planning a dark sky park involves a complete study of facts regarding the specific site. Existing lighting installations are surveyed in detail by recording types of luminaires and lamps and recording their positions in a map. Lighting illuminance levels are measured by photometers and spectra are analyzed using a spectrometer. Sky brightness levels measurements are performed using specialized photometers and light pollution origins are traced using wide-field photography. Finally, a proposal is made for a dark sky park scheme suited to the specific case of the site.

Night-time screen-based media device use and adolescents' sleep and health-related quality of life

OBJECTIVE

The present study investigates the relationship between night-time screen-based media devices (SBMD) use, which refers to use within 1 h before sleep, in both lit and dark rooms, and sleep outcomes and health-related quality of life (HRQoL) among 11 to 12-year-olds.

METHODS

We analysed baseline data from a large cohort of 6616 adolescents from 39 schools in and around London, United Kingdom, participating in the Study of Cognition Adolescents and Mobile Phone (SCAMP). Adolescents self-reported their use of any SBMD (mobile phone, tablet, laptop, television etc.). Sleep variables were derived from self-reported weekday and/or weekend bedtime, sleep onset latency (SOL) and wake time. Sleep quality was assessed using four standardised dimensions from the Swiss Health Survey. HRQoL was estimated using the KIDSCREEN-10 questionnaire.

RESULTS

Over two-thirds (71.5%) of adolescents reported using at least one SBMD at night-time, and about a third (32.2%) reported using mobile phones at night-time in darkness. Night-time mobile phone and television use was associated with higher odds of insufficient sleep duration on weekdays (Odds Ratio, OR = 1.82, 95% Confidence Interval, CI [1.59, 2.07] and OR = 1.40, 95% CI [1.23, 1.60], respectively). Adolescents who used mobile phones in a room with light were more likely to have insufficient sleep (OR = 1.32, 95% CI [1.10, 1.60]) and later sleep midpoint (OR = 1.64, 95% CI [1.37, 1.95]) on weekends compared to non-users. The magnitude of these associations was even stronger for those who used mobile phones in darkness for insufficient sleep duration on weekdays (OR = 2.13, 95% CI [1.79, 2.54]) and for later sleep midpoint on weekdays (OR = 3.88, 95% CI [3.25, 4.62]) compared to non-users. Night-time use of mobile phones was associated with lower HRQoL and use in a dark room was associated with even lower KIDSCREEN-10 score (β = -1.18, 95% CI [-1.85, -0.52]) compared to no use.

CONCLUSIONS

We found consistent associations between night-time SBMD use and poor sleep outcomes and worse HRQoL in adolescents. The magnitude of these associations was stronger when SBMD use occurred in a dark room versus a lit room.

Artificial light at night affects body mass but not oxidative status in free-living nestling songbirds: an experimental study

Artificial light at night (ALAN), termed light pollution, is an increasingly important anthropogenic environmental pressure on wildlife. Exposure to unnatural lighting environments may have profound effects on animal physiology, particularly during early life. Here, we experimentally investigated for the first time the impact of ALAN on body mass and oxidative status during development, using nestlings of a free-living songbird, the great tit (Parus major), an important model species. Body mass and blood oxidative status were determined at baseline (=13 days after hatching) and again after a two night exposure to ALAN. Because it is very difficult to generalise the oxidative status from one or two measures we relied on a multi-biomarker approach. We determined multiple metrics of both antioxidant defences and oxidative damage: molecular antioxidants GSH, GSSG; antioxidant enzymes GPX, SOD, CAT; total non-enzymatic antioxidant capacity and damage markers protein carbonyls and TBARS. Light exposed nestlings showed no increase in body mass, in contrast to unexposed individuals. None of the metrics of oxidative status were affected. Nonetheless, our study provides experimental field evidence that ALAN may negatively affect free-living nestlings' development and hence may have adverse consequences lasting throughout adulthood.

Effect of LED photobiomodulation on fluorescent light induced changes in cellular ATPases and Cytochrome c oxidase activity in Wistar rat

BACKGROUND

Fluorescent light exposure at night alters cellular enzyme activities resulting in health defects. Studies have demonstrated that light emitting diode photobiomodulation enhances cellular enzyme activities.

OBJECTIVE

The objectives of this study are to evaluate the effects of fluorescent light induced changes in cellular enzymes and to assess the protective role of pre exposure to 670 nm LED in rat model.

METHODS

Male Wistar albino rats were divided into 10 groups of 6 animals each based on duration of exposure (1, 15, and 30 days) and exposure regimen (cage control, exposure to fluorescent light [1800 lx], LED preexposure followed by fluorescent light exposure and only LED exposure). Na⁺-K⁺ ATPase, Ca²⁺ ATPase, and cytochrome c oxidase of the brain, heart, kidney, liver, and skeletal muscle were assayed.

RESULTS

Animals of the fluorescent light exposure group showed a significant reduction in Na⁺-K⁺ ATPase and Ca²⁺ ATPase activities in 1 and 15 days and their increase in animals of 30-day group in most of the regions studied. Cytochrome c oxidase showed increase in their level at all the time points assessed in most of the tissues. LED light preexposure showed a significant enhancement in the degree of increase in the enzyme activities in almost all the tissues and at all the time points assessed.

CONCLUSIONS

This study demonstrates the protective effect of 670 nm LED pre exposure on cellular enzymes against fluorescent light induced change.