[Cathepsin K and matrix metalloproteases activity in the bone tissue of OXYS rats with developing osteoporosis].

The comparative study of activity of cysteine protease cathepsin K and matrix metalloproteases (MMPs) in bone tissue of accelerated senescent OXYS rats with early ageing comparatively to Wistar rats of the same age was performed. Early development osteoporosis is a typical feature of OXYS rats. In bone tissue of 3 month old OXYS rats, before appearance of osteoporosis manifestation cathepsin K activity was higher, whereas MMPs activity was lower than in Wistar rats. In Wistar rats (3 and 14 months old) cathepsin K activity of spine was shown to increase, and MMPs activity to decrease. In OXYS rats age-related change of cathepsin K and MMPs activity in bone tissue had the opposite direction. As a result of this there were no differences between Wistar and OXYS rats 14 months old despite the marked osteoporosis in OXYS rats as revealed our early researches. Serum Q2-macroglobulin activity was higher in 14 months old OXYS rats. The role of activation of cathepsin K in bone resorption in the development of osteoporosis in early ageing OXYS rats is discussed.