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Repeated acute stress alters heart morphometry in male and female rats differently
Brenda M Elliott1, Martha M Faraday, Neil E Grunberg
1Department of Medical and Clinical Psychology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA. belliott@usuhs.mil
Insights
Mild daily stress alters rat heart shape and blood volume. Males showed changes in heart dimensions, while females experienced reduced blood volume, revealing sex-specific stress responses in cardiovascular health.
Area of Science:
- Cardiovascular Physiology
- Stress Physiology
- Comparative Anatomy
Background:
- Stress negatively impacts the cardiovascular system.
- Left ventricular hypertrophy is a known heart disease risk factor.
- Sex differences in heart disease suggest varying stress effects.
Purpose of the Study:
- Examine mild stress effects on heart morphology and blood volume.
- Investigate sex-based differences in stress-induced cardiac changes.
- Understand gender disparities in heart disease etiology.
Main Methods:
- Exposed male and female rats to mild daily stress for 14 days.
- Measured heart parameters (length, weight, wall thickness, cavity width) post-stress.
- Assessed total blood volume via ex-sanguination.
Main Results:
- In males, stress decreased heart length and left ventricle cavity width, increasing septal wall thickness (body weight controlled).
- In females, stress significantly reduced total blood volume but did not alter other cardiac measures.
- Findings indicate stress-induced alterations in heart morphology and blood volume with distinct sex-specific patterns.
Conclusions:
- Stress exposure can modify heart morphology and blood volume.
- Significant sex differences exist in the cardiovascular response to stress.
- These findings contribute to understanding gender-based variations in heart disease risk.
Abstract:
Stress exerts deleterious effects on the cardiovascular system. Left ventricular hypertrophy has been identified as a risk factor for heart disease. The effects of stress on other heart parameters, including heart size and heart shape, are not well-characterized. In addition, the extent to which males and females differ in stress effects on these measures has not been examined, but may help to further explain gender differences in heart disease morbidity and mortality. The present experiment examined effects of mild daily stress on heart morphology and blood volume (obtained by ex-sanguination at decapitation) in 39 male and 40 female rats of two strains. Following 14 days of stress exposure, rats were killed and blood volume was measured. Heart length, heart weight, left ventricle cavity width, right ventricle width, lateral wall thickness, anterior wall thickness, posterior wall thickness, and septal wall thickness were measured. In males, after controlling for body weight, stress decreased heart length and left ventricle cavity width and increased septal wall thickness. In females, after controlling for body weight, stress reduced total blood volume, but did not significantly affect other heart parameters. These findings suggest that stress exposure can alter heart morphology and blood volume and that there are sex differences in these effects.