Structural distribution and mechanism of elastic fibers and collagen fibers in ventricular interstitium of aged rats / 解剖学报

ABSTRACT

Objective To investigate the structural distribution features and mechanism of elastic fibers and collagen fibers in ventricular interstitium of aged rats. Methods Five young SD rats (24 weeks) and five old SD rats (104 weeks) were used,and their cardiac function was examined by echocardiography. Modified Weigert elastic fiber staining, immunohistochemistry, immunofluorescence and Western blotting techniques were used to detect the expression changes of type I and IH collagen fibers and their proteins, elastic fibers and their proteins, matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 2 (TIMP-2), respectively. Results The type I and type IH collagen in the ventricular interstitium of aged rats was very sufficient and wrapped around the cardiomyocytes. Compared with the young rats, the content of collagen protein in the ventricular interstitium of the aged rats significantly increased (P<0. 05). Elastic fibers in the ventricular interstitium of the aged rats were and widely distributed. Compared with the young rats, the number of elastic fibers and the level of elastin in the ventricular interstitium of the aged rats significantly decreased (P<0. 05), and the expression levels of MMP-2 and MMP-9 in ventricular muscle of aged rats increased, and the)' were correlated with the level of elastin. The level of TIMP-2 in ventricular muscle of aged rats decreased with age. Conclusion The number of collagen fibers and elastic fibers in ventricular interstitium of aged rats is fluctuated with each other. With the increase of age, the contents of TIMP-2 and elastic fibers in the ventricular interstitium gradually decreased, and the ratio of collagen fibers to elastic fibers is out of balance.