Morphology and mechanical properties of the subrenal aorta in normotensive and hypertensive rats.
OBJECTIVE
This work focuses on the morphological and mechanical changes in the wall of the subrenal aorta in rats suffering from arterial hypertension and chronic renal failure induced by subtotal nephrectomy (NX).


METHODS
The quantitative structural parameters were assessed using stereological methods. The mechanical properties were determined using uniaxial tensile tests.


RESULTS
Morphological results showed no significant differences in the wall structure of NX rats ten days following the subtotal nephrectomy in comparison with the control animals. Pronounced structural changes appeared ten weeks after the nephrectomy. The area of the profile of the arterial lumen, the volume fraction of elastin, and the elastin lamellar number in the tunica media were significantly higher in the NX rats than in the control animals. The values of the volume fraction of the smooth muscle cells in the tunica media and the lamellar unit thickness were significantly lower for the NX animals. Mechanical results showed that both kinds of tissues were characterized by a non-linear response when subjected to the tensile test. The moduli of elasticity of subrenal aortas in control and NX animals were different only for large deformations: NX samples had higher stiffness. The cyclic loading resulted in a time-dependent response for both tissue types.


CONCLUSIONS
The results obtained from the NX rats ten days as well as ten weeks after operation suggested an outward hypertrophy of the aorta. The subrenal aortas of the NX animals had less strength and were less extensible than those of the control animals.
Kochova
Petra
P
Department of Mechanics, Faculty of Applied Sciences, University of West Bohemia, Univerzitni 22, Pilsen, Czech Republic. kochovap@kme.zcu.cz
Tonar
Zbynek
Z
Matejka
Vit M
VM
Sviglerova
Jitka
J
Stengl
Milan
M
Kuncova
Jitka
J
D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology* / Q000503:physiopathology; D001696:Biomechanical Phenomena; D004548:Elasticity; D006977:Hypertension, Renal / Q000473:pathology* / Q000503:physiopathology; D006984:Hypertrophy; D008297:Male; D009392:Nephrectomy; D051381:Rats; D017208:Rats, Wistar; D013718:Tensile Strength