Ascorbic Acid Accumulates in Chondrocytes in Vivo

Introduction: Ascorbic acid’s important role in collagen synthesis is well established. Since humans lack a functional gulonolactone oxidase (GLO) gene for synthesizing ascorbic acid, this nutrient must be provided in the diet and then transported into the chondrocyte for usage. Guinea pigs are one of the few non-primate mammals that also lack the GLO gene so they provided an ideal model for this study. The goal of this study was to evaluate the concentration of total ascorbic acid (oxidized and reduced) in cartilage in vivo under various regimens of ascorbic acid dosing. In order to relate this to cellular levels within the chondrocyte, we normalized the data to genomic DNA. We also sought to compare cartilage to other tissues such as liver and adrenal. Furthermore, to examine the relationship between circulating and tissue levels we looked at ascorbic acid in plasma and synovial fluid.