engleski

Expression of osteoinductive proteins and their inhibitors during osteogenesis

Aim. The aim to determine distribution of the expression of BMP-2, -4 and -7, and their inhibitors (gremlin, noggin, chordin and follistatin) during normal, induced (ectopically), and pathological osteogenesis. Material and methods. Twenty samples of osteophytes of the knee joint were obtained from patients who underwent artificial joint implant surgery Twenty samples of normal articular cartilage and subchondral bone were taken from the knee joint of deceased persons without degenerative changes. The animal material included 150 female rats. The animals were implanted demineralized bone matrix subcutaneously. Protein expression and localization was determined by immunohistochemical analysis and Western blot. Results. In the early phase of osteogenesis, BMP-2 and BMP-4 were significantly expressed, whereas during the late phase, the expression of BMP-7 increased. The expression of bone morphogenetic proteins 2, 4 and 7 varied during developmental phases of ectopic osteogenesis. In the early phase of osteogenesis, BMP-2 and BMP-4 were significantly expressed, whereas during the late phase, the expression of BMP-7 increased. Inhibitors of BMPs were co-expressed with the studied BMP during all phases of osteogenesis. In chondrocytes in the osteophytes, BMP-7 was more expressed than BMP-4, while BMP-2 was not expressed. BMP inhibitors in chondrocytes of the osteophytes were co-expressed with BMP. The expression of BMP and their inhibitors in the cells of bone tissue osteophytes was minimal. Conclusion. During different processes of osteogenesis the expression patterns of BMPs and their inhibitors in cartilage and bone tissue were specific and markedly different. Besides local interaction, BMP and their inhibitors, and the cells whose activity they affect depend on systemic factors. In other words, although the studied proteins - BMP and their inhibitors exhibit immediate antagonistic activity, as a whole, their role is synergistic and involved in the homeostasis of bone tissue.

osteogenesis; bone morphogenetic proteins (2; 4 and 7); chordin; gremlin; noggin and follistatin.

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