Mechanical properties and composition of mesenteric small arteries of simulated microgravity rats with and without daily -G(x) gravitation / 生理学报
Acta Physiologica Sinica
; (6): 107-120, 2012.
Article
em En
| WPRIM
| ID: wpr-335934
Biblioteca responsável:
WPRO
ABSTRACT
The aim of the present study was to evaluate the active and passive mechanical properties and wall collagen and elastin contents of mesenteric small arteries (MSAs) isolated from rats of 28-day simulated microgravity (SUS), countermeasure [S + D: SUS plus 1 h/d -G(x) to simulate intermittent artificial gravity (IAG)] and control (CON) groups. Three mechanical parameters were calculated: the overall stiffness (β), circumferential stress (σ(θ))-strain (ε(θ)) relationship and pressure-dependent incremental elastic modulus (E(inc,p)). Vessel wall collagen and elastin percentage were quantified by electron microscopy. The results demonstrate that the active mechanical behavior of MSAs differs noticeably among the three groups: the active stress-strain curve of SUS vessels is very close to the passive curve, whereas the active σ(θ)-ε(θ) curves of CON and S + D vessels are shifted leftward and display a parabolic shape, indicating that for MSAs isolated from S + D, but not those from SUS rats, the pressure-induced myogenic constriction can effectively stiffen the vessel wall as the CON vessels. The passive mechanical behavior of MSAs does not show significant differences among the three groups. However, the percentage of collagen is decreased in the wall of SUS and S + D compared with CON vessels in the following order: SUS < S + D < CON. Thus, the relationship between passive mechanical behavior and compositional changes may be complex and yet depends on factors other than the quantity of collagen and elastin. These findings have provided biomechanical data for the understanding of the mechanism of postflight orthostatic intolerance and its gravity-based countermeasure.
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Índice:
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Assunto principal:
Fisiologia
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Estresse Mecânico
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Vasoconstrição
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Fenômenos Biomecânicos
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Distribuição Aleatória
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Colágeno
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Ratos Sprague-Dawley
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Simulação de Ausência de Peso
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Elevação dos Membros Posteriores
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Elasticidade
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Acta Physiologica Sinica
Ano de publicação:
2012
Tipo de documento:
Article