MORPHOLOGICAL EFFECTS OF GLYCOSAMINOGLYCANS ON CALCIUM-OXALATE MONOHYDRATE CRYSTALS

The effects of individual glycosaminoglycan (GAG) species on calcium o xalate monohydrate (COM) crystal growth were studied in vitro by the o bservation of crystal morphology grown in a supersaturated calcium oxa late solution in the presence of GAGs using optical and scanning elect ron microscopes. GAGs affected the morphology of COM crystals differen tly depending on the species. The growth rates of the crystals formed in the presence of chondroitin-6-sulfate (ChS-C) were higher in length and lower in width and thickness than those of control crystals. The incorporation of dermatan sulfate or heparin into the crystals formed in the presence of these GAGs was revealed by X-ray microanalysis, whe reas ChS-C was not detected in the crystals grown with it. The experim ent using dicarboxylates, as a simple model of GAG molecules, showed t hat a distance between the side groups was important for their morphol ogical effects. These findings suggested that the different effects of GAGs on the crystal morphology resulted from the differences in their interaction modes with COM crystal faces, that is, the differences in their binding behavior, their inhibition modes of crystal growth, and other roles played after binding to the crystals.