Sex differences in temperature rhythm disruption after traumatic brain injury

Area of Science:

• Neuroscience
• Chronobiology
• Physiology

Background:

• Circadian rhythms regulate essential bodily functions, including body temperature.
• Disruptions to circadian rhythms are linked to adverse health outcomes and are exacerbated by traumatic brain injury (TBI).
• Sex-specific effects of TBI on circadian temperature regulation remain largely unexplored.

Purpose of the Study:

• To investigate sex differences in circadian body temperature rhythms following mild-moderate lateral fluid percussion injury (FPI) in rats.
• To determine if TBI differentially impacts temperature rhythmicity in female versus male rodents.
• To explore potential sex-dependent mechanisms influencing TBI recovery.

Main Methods:

• Adult male and female rats were monitored for body temperature rhythms using passive temperature changes.
• Circadian analysis, including cosinor analysis, was performed at baseline and after sham surgery or FPI.
• Key parameters analyzed included MESOR, amplitude, and acrophase of temperature rhythms.

Main Results:

• Females exhibited higher overall body temperature compared to males.
• Following sham surgery and FPI, the temperature MESOR increased in all groups, with a more pronounced increase in males.
• In females, FPI significantly reduced the amplitude and oscillation frequency of circadian temperature rhythms compared to all other groups, indicating a loss of rhythmicity.

Conclusions:

• TBI induces sex-specific alterations in circadian body temperature rhythms.
• Females demonstrate a significant loss of circadian temperature rhythmicity after TBI, unlike males.
• These sex differences in circadian function following TBI may represent a therapeutic target for improving recovery outcomes.