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Updated: Nov 26, 2025
Transmission Electron Microscopy as the Visualization Technique for Analysis of Circadian Synaptic Plasticity in the Mouse Barrel Cortex
Published on: August 19, 2025
Microglial ablation in rats disrupts the circadian system
Luba Sominsky1, Tamara Dangel1,2, Sajida Malik1
1School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia.
Abstract:
Microglia, the key neuroimmune cells of the central nervous system, are best known for their function in defending an individual from pathogens and injury. Recent findings, including our own, suggest microglia also have several immune-independent roles, including in regulating satiety, promoting memory, and modifying pain responses. Many of these microglia-associated functions are affected by circadian rhythmicity, thus, varying substantially depending upon the time of day. To gain further insight into this link, we used a Cx3cr1-Dtr transgenic Wistar rat model to acutely deplete microglia and examined if this could lead to a disruption in diurnal temperature, metabolism, and activity measures. We also examined if differences in the physiological rhythms corresponded with changes in the expression of key circadian rhythm-regulating genes and proteins. Our data show that in the absence of microglia there is a pronounced disruption of diurnal rhythms in several domains consistent with a shift toward the inactive phase, in conjunction with changes in circadian rhythm-regulating genes and proteins. These data suggest microglia are involved in the regulation of circadian rhythms and indicate an exciting potential to manipulate these cells to improve disrupted circadian rhythms such as with shift-work or jet-lag.
Insights
Microglia, crucial brain immune cells, regulate daily rhythms. Depleting them disrupts temperature, metabolism, and activity, suggesting a role in circadian regulation.
Area of Science:
- Neuroimmunology
- Chronobiology
Background:
- Microglia are central nervous system immune cells involved in pathogen defense and injury repair.
- Emerging evidence highlights immune-independent roles for microglia in satiety, memory, and pain modulation.
- Microglia functions are influenced by circadian rhythms, leading to time-of-day variations.
Purpose of the Study:
- To investigate the role of microglia in regulating diurnal physiological rhythms.
- To determine if acute microglia depletion disrupts temperature, metabolism, and activity patterns.
- To explore the connection between physiological rhythm changes and circadian gene/protein expression.
Main Methods:
- Utilized a Cx3cr1-Dtr transgenic Wistar rat model for acute microglia depletion.
- Monitored diurnal variations in temperature, metabolism, and activity.
- Analyzed the expression of key circadian rhythm-regulating genes and proteins.
Main Results:
- Microglia depletion caused significant disruption of diurnal rhythms.
- Observed a shift towards the inactive phase in physiological measures.
- Detected alterations in the expression of circadian rhythm-regulating genes and proteins.
Conclusions:
- Microglia play a significant role in the regulation of circadian rhythms.
- These findings suggest potential therapeutic strategies targeting microglia for disrupted circadian rhythms, such as those associated with shift work or jet lag.
