Left ventricular size, output, and structure during guinea pig pregnancy

Area of Science:

• Cardiovascular Physiology
• Reproductive Biology
• Animal Models

Background:

• Pregnancy induces significant physiological changes, including cardiovascular adaptations.
• Understanding these changes in animal models is crucial for comparative physiology and human pregnancy research.
• The guinea pig is a relevant model for studying pregnancy due to its gestation period and physiological similarities.

Purpose of the Study:

• To investigate the cardiac hemodynamic and morphometric changes during pregnancy in guinea pigs.
• To determine how left ventricular (LV) function and structure are altered by gestation.
• To establish a comprehensive profile of cardiovascular adaptations in pregnant guinea pigs.

Main Methods:

• Comparison of time-bred pregnant guinea pigs with age- and weight-matched controls.
• Hemodynamic measurements and LV pressure-volume loop analysis during late gestation (days 59-68).
• Assessment of LV morphometry, including cellular and subcellular volumes.

Main Results:

• Pregnant guinea pigs showed increased maternal weight and O2 consumption, cardiac output, and stroke volume when indexed for lean body mass.
• Left ventricular (LV) mass remained unchanged, but passive LV pressure-volume curves shifted rightward.
• No significant alterations were observed in LV morphometry, myocyte volumes, or elastic modulus.

Conclusions:

• Pregnancy in guinea pigs enhances cardiac output and stroke volume without increasing LV mass or altering its fundamental structure.
• The observed hemodynamic changes are adaptive, supporting the increased metabolic demands of gestation.
• The guinea pig serves as a valuable model for studying pregnancy-induced cardiovascular adjustments.