Chondrocyte
A chondrocyte is the resident cell of cartilage, the cell that makes and maintains the surrounding tissue. In articular cartilage, chondrocytes make up only about 2% of the volume.
Also called cartilage cell.
Chondrocytes arise from mesenchymal stem cells and sit scattered through the material they make, each one responsible for turning over the matrix in its immediate neighbourhood (Sophia Fox 2009). Near the joint surface they are flatter, smaller and more closely packed than deeper down (Sophia Fox 2009).
Because cartilage has no blood vessels, nutrients reach chondrocytes with the water that moves through the tissue (Sophia Fox 2009), and the main antioxidant they rely on, glutathione, is one they make themselves. In growth-plate cartilage during bone development, glutathione made from glutamine kept reactive oxygen species down and let chondrocytes survive without a blood supply (Stegen 2020).
With age the balance shifts. A review describes older chondrocytes producing more reactive oxygen species than their antioxidant capacity can handle (Bolduc 2019), and in human cartilage cells, more than twice as many cells from donors aged 50 and over died under oxidant stress as cells from donors aged 18 to 49 (Del Carlo 2003).
Sources
- Sophia Fox AJ, Bedi A, Rodeo SA. The basic science of articular cartilage: structure, composition, and function. Sports Health 2009.
- Stegen S, Rinaldi G, Loopmans S et al. Glutamine Metabolism Controls Chondrocyte Identity and Function. Dev Cell 2020.
- Bolduc JA, Collins JA, Loeser RF. Reactive oxygen species, aging and articular cartilage homeostasis. Free Radic Biol Med 2019.
- Carlo MD Jr, Loeser RF. Increased oxidative stress with aging reduces chondrocyte survival: correlation with intracellular glutathione levels. Arthritis Rheum 2003.
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