Ascorbic acid accumulates in cartilage in vivo

Stabler TV, Kraus VB · Clinica Chimica Acta

The transport biology shows up as a concentration gradient in a live animal: ascorbate was higher in synovial fluid than in paired plasma, and higher in cartilage than in paired synovial fluid, with normalized cartilage levels sitting between liver and adrenal gland. All tissues showed saturation — a large gap between low and medium dose, a small one between medium and high.

Population

Guinea pigs across a range of dietary ascorbic acid doses

Intervention

Dose-response measurement of ascorbic acid in plasma, synovial fluid and cartilage

Limitations

Guinea pigs, chosen because like humans they cannot synthesise ascorbate. No joint outcome was measured. The saturation shape is the practically important finding and it argues against high doses on distribution grounds alone.