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Updated: Aug 15, 2026
Fetal Echocardiography and Pulsed-wave Doppler Ultrasound in a Rabbit Model of Intrauterine Growth Restriction
Published on: June 29, 2013
Polyamine metabolism during the perinatal development of the rabbit right and left ventricle
Insights
Rabbit heart development shows significant left ventricular growth driven by ornithine decarboxylase (ODC) activity and putrescine accumulation, while the right ventricle shows decreased ODC activity and weight post-birth.
Area of Science:
- Cardiovascular Physiology
- Developmental Biology
- Biochemistry
Background:
- Cardiac development involves complex changes in ventricular mass and cellular activity.
- Ornithine decarboxylase (ODC) is a key enzyme in polyamine synthesis, crucial for cell growth and proliferation.
Purpose of the Study:
- To investigate the changes in right ventricular (RV) and left ventricular (LV) free wall weights, ODC activity, and polyamine content during postnatal development in rabbits.
- To elucidate the molecular mechanisms underlying the differential growth of the RV and LV in early life.
Main Methods:
- Determination of free wall weights, ODC specific activity, and polyamine content (putrescine, spermidine, spermine) in rabbit hearts at various postnatal ages (fetal, 1, 2, 7, 14, 21 days).
- Comparative analysis of RV and LV parameters to understand differential growth patterns.
Main Results:
- Significant increase in LV free wall weight and decrease in RV free wall weight between days 1-7, leading to a doubled LV/RV mass ratio by day 7.
- Increased LV ODC specific activity and putrescine content post-birth, correlating with preferential LV growth.
- Transient increase in spermidine and spermine in both ventricles, with distinct patterns of putrescine accumulation.
Conclusions:
- Preferential postnatal growth of the rabbit left ventricle is characterized by increased ornithine decarboxylase activity and putrescine accumulation.
- These biochemical changes in the LV, particularly ODC activity, play a critical role in driving its growth relative to the RV after birth.
Abstract:
The right ventricular (RV) and left ventricular (LV) free wall weights, ornithine decarboxylase (ODC) specific activity and polyamine content were determined in fetal, 1-, 2-, 7-, 14-, and 21-day-old rabbit hearts. There was a significant increase in the LV free wall weight and a decrease in RV free wall weight between 1-7 days. By day 7 the LV/RV mass ratio doubled and reached a ratio comparable to that seen in adult rabbit hearts. The rate of change in the LV and RV free wall weights were comparable after day 7. There was a significant increase in LV ODC specific activity and a decrease in RV ODC specific activity after birth. The LV ODC specific activity was significantly greater than RV ODC specific activity in both 1 and 2 day old rabbit hearts whereas they were not significantly different in 7 and 14 day old rabbit hearts. The molar content (nmoles/mg wet weight or nmoles/mg protein) of putrescine decreased approximately 3-fold after birth in the RV but increased approximately 2-fold in the LV. The molar content of spermidine and spermine was transiently increased after birth (1 day old) in both RV and LV with approximately a 2-fold increase in spermidine and a 2.5-fold (LV) and 4-fold (RV) increase in spermine content. The increase in LV putrescine content after birth was due, at least in part, to the observed increase in ODC specific activity in the LV free wall. The putrescine/spermidine ratio increased in the LV and decreased in the RV immediately after birth up to day 7. As opposed to the short-lived increase in spermidine and spermine observed in both the RV and the LV free wall, increased ODC specific activity and putrescine accumulation uniquely characterized the preferential growth of the LV between day 1 and 7.
