Aging is associated with increased activities of matrix metalloproteinase-2 and -9 in tenocytesReportar como inadecuado

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BMC Musculoskeletal Disorders

, 14:2

Pathophysiology of musculoskeletal disorders


BackgroundMost tendon pathology is associated with degeneration, which is thought to involve cyclic loading and cumulative age-related changes in tissue architecture. However, the association between aging and degeneration of the extracellular matrix ECM in tendons has not been investigated extensively.

MethodsWe examined tenocytes from Achilles tendons taken from rats of three different ages 2, 12, and 24 months. Tenocyte viability was assessed using the 3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide MTT assay. Quantitative real-time polymerase chain reaction PCR was used to determine the levels of mRNAs that encode type-I collagen, matrix metalloproteinase MMP-2 and −9, tissue inhibitor of metalloproteinase TIMP-1 and −2 and transforming growth factor TGF-β1. Gelatin zymography was used to evaluate the enzymatic activities of MMP-2 and −9. Furthermore, the concentration of TGF-β1 in conditioned medium was evaluated using enzyme-linked immunosorbent assay ELISA.

ResultsThe results of the MTT assay showed that the number of viable tenocytes decreased with age. No differences were observed in the levels of mRNAs that encode type-I collagen and TGF-β1 among the three age groups, and the TGF-β1 concentration did not change with age. However, mRNAs that encode MMP-2 and −9 were significantly more abundant in tenocytes from the aging group, and gelatin zymography revealed that the enzymatic activities of MMP-2 and −9 also increased significantly with age. Furthermore, as compared with young group, mRNAs that encode TIMP-1 and −2 were significantly decreased in tenocytes from the aging group.

ConclusionsActivities of MMP-2 and MMP-9 in tenocytes increase with age. This might provide a mechanistic explanation of how aging contributes to tendinopathy or tendon rupture with age.

KeywordsAging Collagen Matrix metalloproteinase Tenocytes Transforming growth factor-beta 1 Electronic supplementary materialThe online version of this article doi:10.1186-1471-2474-14-2 contains supplementary material, which is available to authorized users.

Tung-Yang Yu, Jong-Hwei S Pang contributed equally to this work.

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Autor: Tung-Yang Yu - Jong-Hwei S Pang - Katie Pei-Hsuan Wu - Max J-L Chen - Chien-Hung Chen - Wen-Chung Tsai


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