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Cardiac function and morphology with aging in the spontaneously hypertensive rat
The American Journal of Physiology
|October 1, 1979
Summary
Chronic hypertension in spontaneously hypertensive rats (SHR) leads to reduced cardiac output and stroke volume by 90 weeks of age. Ventricular remodeling, including left and right ventricular hypertrophy, contributes to this decline in cardiac function.
Area of Science:
- Cardiovascular Physiology
- Animal Models of Hypertension
Background:
- Hypertension is a major risk factor for cardiovascular disease.
- Understanding the cardiac adaptations to chronic pressure overload is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the effects of chronic pressure load on cardiac function and morphology in spontaneously hypertensive rats (SHR) compared to normotensive Wistar rats (WKY and NWR).
Main Methods:
- SHR, WKY, and NWR rats were studied at various ages (13, 25, 52, 90 weeks) under anesthesia.
- Cardiac function was assessed by measuring cardiac output and stroke volume during intravenous fluid infusion.
- Cardiac morphology was evaluated through measurements of ventricular dimensions and wall thickness.
Main Results:
- Spontaneously hypertensive rats showed a marked reduction in peak cardiac output and stroke volume at 90 weeks of age.
- Left ventricular dimensions increased disproportionately in SHR, indicating concentric hypertrophy.
- Significant thickening of the left ventricle free wall and hypertrophy of the right ventricle were observed in older SHR.
Conclusions:
- Chronic hypertension induces significant cardiac remodeling in SHR, characterized by ventricular hypertrophy.
- These structural alterations in cardiac architecture correlate with a decline in cardiac pumping ability in long-standing hypertension.