Prolonged Blue Light Exposure Does Not Elicit Adverse Changes to Physical Activity in Male Mice

Abstract

Listen

Translate article

Color plays a role in human and animal circadian rhythm patterns, behaviors, and emotional responses. Environments containing blue colors improve information storage in humans and reproductive success in animals; however, environments containing blue light influence behavioral and emotional responses in rodents and humans in adverse ways. Exposure to blue light alters sleeping patterns, induces the stress response, and elicits depressive behaviors. These initial responses then affect awake time functionality and productivity. Under normal physiological conditions, mice, when provided access to an in-cage running wheel, exhibit high levels of nocturnal physical activity behavior. It is unknown if this nocturnal behavior changes after prolonged blue light exposure. Therefore, this project's hypothesis is wheel running utilization decreases after exposure to blue light during the diurnal restful period in the normally nocturnal mouse. The purpose of this study was to expose mice to overhead blue LED lights during the daytime rest period and to examine nighttime physical activity patterns. Daily wheel running distance, duration, and speed monitoring in C57BL/6j male mice (n=12) occurred for 21 days. During the second week of the study, an experimental group (n=6) underwent blue light-emitting diode (LED) light exposure, and a control group (n=6) experienced white LED light exposure at the same intensity. The lights were on a 12-hour light/dark cycle at full brightness during the exposure period. Differences in wheel running distance, duration, and speed following exposure to blue LED light were assessed via individual two-way (group by phase of study) ANOVAs. Blue LED light exposure did not appear to affect average daily wheel running distance [F=0.42, p=0.57], duration [F=0.79, p=0.42], or speed [F=0.08, p=0.87]. Following exposure to blue LED light during the restful diurnal period, wheel running remained stable. This lack of effect indicates that mechanisms may exist to protect mice from the adverse effects associated with blue light exposure, especially as it pertains to participating in routine physical activity. These postulated mechanisms may allow robust participation in physical activity-related behaviors in these animals and represent a potential biological regulator that could aid in mitigating the adverse effects of blue light exposure experienced in humans. All funding for this research was provided by the Union University Department of Biology. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.