Micromechanical properties of chondrocytes and chondrons: relevance to articular cartilage tissue engineering

Abstract

Articular cartilage is a highly mechanical tissue, performing multiple functions to ensure proper joint movement. Degradation of this tissue may be due to improper loading conditions that lead to a debilitating condition known as osteoarthritis. Furthermore, it is believed that mechanical signals transmitted from the tissue to cellular levels are necessary for the production of essential extracellular matrix components responsible for cartilage viability. Examinations of the tissue on its most rudimentary level elucidate mechanical regimens related to cartilage health and disease. A fundamental unit approach has been employed to study the biomechanical properties of single cells with discrete pericellular and extracellular matrix layers. This approach enables researchers to develop definitive relationships between mechanical stimulation and changes in gene expression corresponding to regenerative or catabolic processes. The knowledge gained from these studies sheds light on the etiology of osteoarthritis and elucidate the mechanical loading regimens useful for promoting articular cartilage health. This review article discusses the micromechanical environment of the cartilage cell, the chondrocyte, and the mechanical models and experimental techniques utilized to examine its physical characteristics. This information is then related to changes in cellular behavior and its potential toward tissue engineering of articular cartilage.

Biomechanical properties of single chondrocytes and chondrons determined by micromanipulation and finite-element modelling

“…Most of these techniques required cells to be anchorage-dependent (Ofek & Athanasiou 2007), while micropipette aspiration and AFM in conjunction *Author for correspondence (z.zhang@bham.ac.uk).…”

Biomechanics of single chondrocytes under direct shear

“…These results improve our knowledge of the chondrocyte micromechanical environment and intracellular changes in response to applied loads. A firm understanding of the physical characteristics of single chondrocytes may shed light on the role of mechanical forces in promoting cartilage regeneration or degeneration (Ofek and Athanasiou 2007;Shieh and Athanasiou 2007).…”

“…The particular stress and strain fields that the chondrocyte experiences within its microenvironment are influenced by its physical properties relative to its immediate tissue matrix surroundings (Guilak and Mow 2000). Cellular interpretations of these mechanical signals through mechanotransductive pathways may induce either catabolic or anabolic gene expression changes, thereby altering the essential extracellular matrix synthesis for cartilage tissue (Ofek and Athanasiou 2007). In addition, chondrocyte mechanical characteristics will affect cellular deformations and the transmission of direct strain to the nucleus (Guilak 1995;Ofek et al 2009), which also alters biosynthetic activity (Buschmann et al 1996;Leipzig and Athanasiou 2008).…”

Multiscale Mechanics of Articular Cartilage: Potentials and Challenges of Coupling Musculoskeletal, Joint, and Microscale Computational Models

“…While experimental studies at the body and joint level have explored functional mechanics of the cartilage from a load sharing perspective, tissue and cell level studies commonly targeted the basic mechanical properties of chondrocytes and chondrons 120 and the biomechanics of the cartilage in relation to its micro-mechanical and chemical environment 140 . Much of the information currently available on chondrocyte response to mechanical stress has been determined using tissue explant culture experiments, which provide a more controlled mechanical and biochemical environment than the in vivo condition (e.g.…”