Bone matrix glycosaminoglycans and osteoporosis development in early aging OXYS rats

Proteoglycans play a crucial role in bone tissue formation promoting consolidation of collagen fibers and bonds between them and mineral crystals. The composition of extracellular matrix proteoglycans was analyzed in early aging OXYS rats with signs of early osteoporosis versus Wistar rats at the age of 2, 4, 6, and 8 months. It was found that bone mineral density in two month OXYS rats was lower than in age-matched Wistar rats. It increased only till 6 month of age in OXYS rats, and during the whole observation period in Wistar rats. Formation of peak bone mass in Wistar rats was accompanied by change in composition of proteoglycan pools in bone tissue matrix: accumulation of macromolecular keratan sulfate-containing proteoglycans, and decrease of uronic acid and sulfated glycosaminoglycan content. OXYS rats were noted for accumulation of micro- and macromolecular proteoglycans: uronic acids and sulfated glycosaminoglycans. Chondroitin sulfate AC and dermatan sulfate were accumulated in OXYS rat bone tissue with the increase in mineral density difference. Keratin sulfate was completely absent here, in contrast to Wistar rats.