ABSTRACT
The structural and functional reorganization of the synovial membrane of the knee joint capsule was studied in 22 individuals of mature age (30-65 years) of both genders with the use of light and electron microscopy, histochemistry, immunohistochemistry and morphometry. The morpho-functional peculiarities of the synovial membrane remodeling in the II period of mature age included: increase the in the synovial intima thickness; significant accumulation of type IV collagen at the border of synovial intima with the subintimal fibrovascular layer of synovial membrane; activation of matrix metalloproteinases MMP-2 and MMP-9; increased cell proapoptotic activity in synovial intima. Collectively, these changes may initiate the disturbances in fluid production and the development of the degenerative-dystrophic processes in the articular cartilage at this stage of ontogenesis.