Type II collagen
Type II collagen is the main collagen of articular cartilage, forming the fibre network that gives the tissue its strength. It is made by chondrocytes, the cartilage cells.
Also called collagen II, collagen type II, COL2A1 (its gene).
Like all collagens it is a triple helix of three protein strands, with glycine at every third position along each strand. That makes glycine supply a real question for collagen-making cells: in cow cartilage cells in the lab, raising glycine above 1 mM increased type II collagen production by 60 to 75%, a larger and longer-lasting effect than extra proline or lysine (de Paz-Lugo 2018).
Researchers track it as a sign of healthy cartilage-cell activity. In rats, oral NAC held back both the rise in MMP13 and the loss of type II collagen in a model of osteoarthritis (Kaneko 2019), and alpha-lipoic acid raised collagen type II gene activity in another rat model (Wang 2016). In human osteoarthritic cartilage cells, switching on Nrf2 with a drug increased type II collagen gene expression (Taylor 2023).
Sources
- de Paz-Lugo P, Lupiáñez JA, Meléndez-Hevia E. High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis. Amino Acids 2018.
- Kaneko Y, Tanigawa N, Sato Y et al. Oral administration of N-acetyl cysteine prevents osteoarthritis development and progression in a rat model. Sci Rep 2019.
- Wang J, Sun H, Fu Z et al. Chondroprotective effects of alpha-lipoic acid in a rat model of osteoarthritis. Free Radic Res 2016.
- Taylor EL, Collins JA, Gopalakrishnan P et al. Age and oxidative stress regulate Nrf2 homeostasis in human articular chondrocytes. Osteoarthritis Cartilage 2023.
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