Cellular Mechanisms of Bioresorption of a Porous 3D Matrix Based on Chitosan

— Highly porous three-dimensional (3D) cylindrical matrices with a diameter of 1.3 mm were obtained by lyophilization of the chitosan solution. The matrix was implanted into rat muscle tissue and after12 months underwent complete resorption. Cellular mechanisms of matrix bioresorption were examined by histological and immunohistochemical methods in vivo after1, 2, 6, 12, 24, 36, and 48 weeks. The role of CD68 + cells, mainly giant multinucleated of foreign body cells, has been investigated. Chronic aseptic inflammation is not accompanied by the activation of mast cells. It shows the bioinertness of the matrix material and allows us to recommend this matrix for use in regenerative medicine, tissue engineering, and cell transplantology.