TY - JOUR
T1 - Alterations in structure of elastic laminae of rat pulmonary arteries in hypoxic hypertension
AU - Liu, S. Q.
PY - 1996/11
Y1 - 1996/11
N2 - The effect of hypoxic hypertension on the remodeling process of the elastic laminae of the rat hilar pulmonary arteries (PAs) was studied by electron microscopy. Rats were exposed to hypoxia (10% O2) for periods of 0.5, 2, 6, 12, 48, 96, 144, and 240 h. Changes in the structure of the PA elastic laminae were examined and analyzed with respect to changes in the PA wall tensile stress. The PA blood pressure increased rapidly within the first several hours of hypoxia and reached a stable level within 2 days, whereas the PA wall tensile stress increased initially due to elevated blood pressure and then decreased after 48 h due to vessel wall thickening and returned to the control level after 4 days. In association with these changes, the elastic laminae, which appeared homogeneous in normal control rats, changed into structures composed of randomly oriented filaments and edematous contents with an increase in the volume during the early period of hypoxia and regained their homogeneous appearance and normal volume after 4 days. The changes in the elastic laminae were correlated with changes in the tensile stress. These changes were associated with a transient decrease in the stiffness of the PAs. In hypoxic rats given nifedipine, no change was found in the blood pressure, the tensile stress, or the structure of the elastic laminae of the PAs despite continuous exposure to hypoxia. These results suggested that altered tensile stress in the PA wall played a critical role in the initiation and regulation of structural changes in the elastic laminae and that these changes might contribute to alterations in the mechanical properties of the PA in hypoxic hypertension.
AB - The effect of hypoxic hypertension on the remodeling process of the elastic laminae of the rat hilar pulmonary arteries (PAs) was studied by electron microscopy. Rats were exposed to hypoxia (10% O2) for periods of 0.5, 2, 6, 12, 48, 96, 144, and 240 h. Changes in the structure of the PA elastic laminae were examined and analyzed with respect to changes in the PA wall tensile stress. The PA blood pressure increased rapidly within the first several hours of hypoxia and reached a stable level within 2 days, whereas the PA wall tensile stress increased initially due to elevated blood pressure and then decreased after 48 h due to vessel wall thickening and returned to the control level after 4 days. In association with these changes, the elastic laminae, which appeared homogeneous in normal control rats, changed into structures composed of randomly oriented filaments and edematous contents with an increase in the volume during the early period of hypoxia and regained their homogeneous appearance and normal volume after 4 days. The changes in the elastic laminae were correlated with changes in the tensile stress. These changes were associated with a transient decrease in the stiffness of the PAs. In hypoxic rats given nifedipine, no change was found in the blood pressure, the tensile stress, or the structure of the elastic laminae of the PAs despite continuous exposure to hypoxia. These results suggested that altered tensile stress in the PA wall played a critical role in the initiation and regulation of structural changes in the elastic laminae and that these changes might contribute to alterations in the mechanical properties of the PA in hypoxic hypertension.
KW - elastic laminae
KW - hypoxic hypertension
KW - mechanical stress
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U2 - 10.1152/jappl.1996.81.5.2147
DO - 10.1152/jappl.1996.81.5.2147
M3 - Article
C2 - 8941540
AN - SCOPUS:0029852534
VL - 81
SP - 2147
EP - 2155
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 5
ER -