[Quantitative analyses of glycosaminoglycans in tear fluids in normal human eyes and eyes with corneal epithelial disorders].

The existence and pathophysiological role of glycosaminoglycans in the tear fluid in humans was investigated using quantitative analyses of hyaluronic acid and chondroitin sulfate in the tear fluid. The subjects were 42 eyes of 31 normal controls, 9 eyes of 9 patients with superficial punctate keratitis (SPK), and 13 eyes of 13 patients with epithelial defect. After an instillation of 100 microliters saline solution in the conjunctival sac, as much tear fluid as possible was collected from the lower cul-de-sac. The glycosaminoglycans in the tears were then treated with chondroitinase ABC to make fractions of unsaturated disaccharides. The quantities of disaccharides were determined by high-performance liquid chromatography. Concentrations were expressed as nanomoles of unsaturated disaccharides per protein in the tears. The concentrations of hyaluronic acid and chondroitin sulfate in the normal controls were 0.07 +/- 0.12(n mol/mg protein) and 6.91 +/- 3.63 (n mol/mg protein), respectively. The mean concentration of hyaluronic acid was significantly higher in patients with epithelial erosion than in normal controls, whereas the mean concentration of chondroitin sulfate was significantly lower in patients with epithelial erosion than in normal controls. There was no significant difference in the concentration of glycosaminoglycans between the patients with SPK and normal controls. The results of our study suggest that glycosaminoglycans are synthesized and endogenously secreted into the tear fluids and, especially in the case of hyaluronic acid, may play an important role in corneal epithelial wound healing in patients with epithelial erosion.