Aging is associated with increased activities of matrix metalloproteinase-2 and -9 in tenocytes

Abstract

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.

In-vitro studies on antioxidant, anti-melanogenic and anti-wrinkle effects of medicinal plant Glycyrrhiza uralensis

“…MMPs are among the major enzymes responsible in the degradation of extracellular matrix which contain diverse biomolecules including collagen and gelatin (Sardy, 2009). Among the several types of MMPs, gelatinases (MMP-2 and -9) cleave soluble type-IV and type-I collagen (Yu et al, 2013).…”

Tissue-Specific Ageing of Rat Tendon-Derived Progenitor Cells

“…Although it is known that tendon ageing affects biomechanical properties and extracellular matrix metabolism [13], there is little known about cellular ageing in tendons. It has, however, been previously reported that tendon cell density is reduced with age.…”

Role of Metalloproteinases in Tendon Pathophysiology

“…Finally, activities of MMP-2 and MMP-9 in tenocytes increase with age. This might further provide a mechanistic explanation of how MMPs and aging contributes to tendinopathy or tendon rupture [105].…”