Immunohistochemical and Electron Microscopic Study of the Biodegradation Processes of Chitin and Chitosan Implanted in Rat Alveolar Bone

Abstract

histochemical and electron microscopic study of the biodegradation processes of chitin and chitosan implanted in rat alveolar bone. Oral Med Pathol 2005; 10: 131-138, ISSN 1342-0984 The present study was designed to investigate histochemically the biodegradation processes of chitin and chitosan implanted in rat alveolar bone. Lysozyme was immunohistochemically detected using postembedding immunogold labeling. The degradation process was ultrastructurally observed using the lectin-colloidal gold technique with electron microscopy. Three groups of chitin were specially prepared according to their degree of deacetylation: 100% deacetylated chitin (DDAC 100); 50% (DDAC 50); and 0% (DDAC 0). The present immunohistochemical study indicated that lysozyme expression was not detected in the DDAC 100 group. Furthermore, electron microscopy clearly demonstrated that the contour of implanted chitosan changed over time, and that chitosan-like fragments were present in the phagosomes in the DDAC 50 and 100 groups. These findings strongly suggest that phagocytes, such as multinuclear cells, are easily supplied in bone tissue and that the phagocytosis is more effective than enzymatic digestion for chitin and chitosan biodegradation in bone tissue. DDAC 100 should be a suitable biomaterial for bone surgery and bone regeneration therapy.

Fabrication and Characteristics of Chitosan Sponge as a Tissue Engineering Scaffold

“…We previously reported an investigation of the biodegradation processes of chitosan fibers implanted in the bone tissue and found that it should be a suitable biomaterial for bone surgery and bone regenerative medicine [ 51 ]. It was suggested that chitosan -based materials bind to growth factors and release them in a controlled manner due to their cationic nature and predictable degradation rate.…”

The increasing of odontoblast-like cell number on direct pulp capping of Rattus norvegicus using chitosan

“…The degree of deacetylation of chitosan, could also affect the biological character of chitosan, including biodegradation of chitosan caused by lysozyme enzyme produced by inflammatory cells and macrophages neutrophil. 7 Actually, chitosan is a source of the active N-acetyl-D-glucosamine dimer, therefore if it is applied to the wound area, it will make inflammatory cells release lysozyme. 3 Neutrophils produced by inflammatory cells, furthermore, will migrate into the wound area several hours after the injury and will reach a maximum concentration in about 24 hours.…”

“…9 Therefore, if chitosan containing the active N-acetyl-D-glucosamine dimer experiences biodegradation, it will form cross-linked with glycosaminoglycan and glycoprotein which plays a role in biological processes, including both the cell and matrix interactions and the activation of growth factors. 7 Growth factors, such as bone morphogenetic protein-2 (BMP-2) which is a superfamily of transforming growth factor b (TGF-b) then will stimulate the differentiation of osteoblastic-cell. 10 Thus, chitosan is able to accelerate wound healing process through fibrinogenic mediators, such as growth factors.…”