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Ontogenic development of the elastic component of the aortic wall in spontaneously hypertensive rats
R B Iredale1, C A Eccleston-Joyner, R B Rucker
1Dept. of Human Physiology, University of California, Davis 95616.
Insights
Genetic hypertension in rats shows increased aortic elastin and structural differences early in development. These arterial wall changes are evident both before and after birth in spontaneously hypertensive rats compared to controls.
Area of Science:
- Cardiovascular Physiology
- Developmental Biology
- Hypertension Research
Background:
- Neonatal spontaneously hypertensive rats (SHR) exhibit elevated arterial pressure compared to normotensive WKY controls.
- Pre-existing cardiovascular system alterations are noted in neonatal SHR.
Purpose of the Study:
- To investigate early developmental differences in the aortic wall's elastic component.
- To compare elastin accumulation patterns in fetal and neonatal SHR versus WKY rats.
Main Methods:
- Analysis of aortic wall structure in fetal (gestation days 17, 19, 21-22) and neonatal (postnatal days 1, 7, 14, 21) SHR and WKY rats.
- Quantification of elastin concentration, aortic cross-sectional area, and lamellar unit number.
Main Results:
- SHR exhibit a higher concentration of elastin in the aortic wall compared to WKY rats.
- A larger aortic cross-sectional area and an increased number of lamellar units were observed in SHR.
- These structural differences were present both prenatally and postnatally.
Conclusions:
- Differences in aortic wall structure associated with genetic hypertension are established early in development.
- Elastin accumulation patterns differ significantly between hypertensive and normotensive animal models from early developmental stages.
Abstract:
In the neonatal stage of development in spontaneously hypertensive rats (SHR), previous studies have shown that arterial pressure is already significantly increased over that of normotensive WKY controls and that other hypertensive characteristics of the cardiovascular system are also in evidence. The present study describes early development of the elastic component of the aortic wall in fetal (days 17, 19, 21-22 of gestation) and neonatal (days 1, 7, 14, 21 of age) SHR and WKY, to determine whether the early pattern of elastin accumulation differs significantly in hypertensive and normotensive animals. The data indicate that in SHR there is a greater concentration of elastin in the aortic wall, a larger cross-sectional area and an increase in the number of lamellar units, both pre- and postnatally. We conclude that the differences in arterial wall structure which are associated with genetic hypertension are established early in development.