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Updated: May 21, 2026
A Rat Model of Mild Intrauterine Hypoperfusion with Microcoil Stenosis
Published on: January 7, 2018
Low-dose thromboxane A2 receptor stimulation promotes closure of the rat ductus arteriosus with minimal adverse
Tomohiro Yokota1, Takashi Aida, Yasuhiro Ichikawa
1Department of Life Science and Medical Bioscience, Waseda University Graduate School of Advanced Science and Engineering, Tokyo, Japan.
Insights
Stimulating the thromboxane A(2) receptor (TP) shows promise for closing the patent ductus arteriosus (PDA) in premature infants. Low-dose TP stimulation effectively constricts the DA with minimal side effects in neonatal rats.
Area of Science:
- Neonatal physiology
- Cardiovascular research
- Pharmacology
Background:
- Patent ductus arteriosus (PDA) is a critical complication in premature infants.
- Current treatments like cyclooxygenase inhibitors have limited efficacy.
- Prostaglandin E(2) is a potent vasodilator of the ductus arteriosus (DA).
Purpose of the Study:
- To investigate the potential of thromboxane A(2) receptor (TP) stimulation to promote DA closure.
- To evaluate the vasoconstrictive effects of TP agonists on the DA.
Main Methods:
- Utilized a rapid whole-body freezing method to measure vessel inner diameter.
- Administered selective TP agonists (U46619 and I-BOP) to fetal and postnatal PDA models.
- Compared vasoconstriction in the DA versus the aorta ex vivo.
Main Results:
- Selective TP agonists dose-dependently constricted the fetal DA at embryonic days 19 and 21.
- U46619 demonstrated vasoconstrictive effects in both premature and hypoxia-induced PDA models.
- U46619 constricted the DA ex vivo more effectively than the aorta ex vivo.
- Low-dose U46619 (≤0.05 mg/g) showed minimal effects on other vessels and no microthrombosis.
Conclusions:
- Low-dose TP stimulation effectively constricts the DA in neonatal rats with minimal adverse effects.
- TP stimulation represents a potential alternative vasoconstrictor for treating PDA.
Background:
Patent ductus arteriosus (PDA) is a common life-threatening complication among premature infants. Although cyclooxygenase inhibitors are frequently used to treat PDA, as they inhibit the synthesis of prostaglandin E(2), the most potent vasodilator in the ductus arteriosus (DA), their efficacy is often limited. As thromboxane A(2) (TXA(2)) induces vascular contraction via the TXA(2) receptor (TP), we hypothesized that TP stimulation would promote DA closure.
Method:
To measure the inner diameter of the vessels, a rapid whole-body freezing method was used.
Results:
Injection of the selective TP agonists U46619 and I-BOP constricted the fetal DA at embryonic day 19 (e19) and e21 in a dose-dependent manner. Of note, U46619 also exerted a vasoconstrictive effect on two different types of postnatal PDA models: premature PDA and hypoxia-induced PDA. We also found that U46619 constricted the ex vivo DA ring to a greater extent than it constricted the ex vivo aorta. Furthermore, we found that U46619 at lower concentrations (up to 0.05 mg/g of body weight) had a minimal vasoconstrictive effect on other vessels and did not induce microthrombosis in the pulmonary capillary arteries.
Conclusion:
Low-dose TP stimulation constricts the DA with minimal adverse effects at least in rat neonates and our results could point to an alternative potent vasoconstrictor for PDA.
