RESUMEN
Aims: This experimental study aimed to evaluate the effects of a three-dimensional matrix of chitosan-gelatin (CG) associated with 1% hyaluronic acid (HA) on gingival healing and repairing of intrabuccal bone defects in rats. Materials and methods: Standardized bone defects were created in the region of the upper 1st molars of rats. Study groups were created according to bone defects (n=6/group) treatment: Control group (CO); blood clot; HA group; CG group, and HA+CG group. After 7 and 21 days, the animals were sacrificed for histological and histomorphometric analysis. Bone formation was quantified as the percentage of newly synthesized collagen, visualized by Gomori's trichromic. Clinical/macroscopic evaluation was based on predetermined scores of gingival healing. Results: Treatment with HA improved gingival healing at day 7, but no statistical differences were found among groups at day 21. The morphometric analysis demonstrated better results after the treatment of bone defects with both HA and CG on day 21. The three-dimensional structure of CG prevented the invasion of epithelial tissue into the defect, preserving its original volume. Conclusions: Isolated use of a chitosan-gelatin osteoconductive matrix promoted greater bone deposition and preserved the volume of the surgical site, irrespective of the presence of hyaluronic acid.
Asunto(s)
Materiales Biocompatibles , Quitosano , Animales , Regeneración Ósea , Colágeno , Ácido Hialurónico , RatasRESUMEN
Considering the potential use of growth factors carried by liposomes for bone repair, this study aimed to assess the progress of bone healing process in injured alveoli of rats after administering EGF within liposomes. For this assessment we used 48 male Wistar rats that had their maxillary second molar extracted and separated into 5 groups: sockets filled with blood clot (BC), treated with empty liposome (L), PBS (P), EGF in PBS (EGF-P) and EGF in liposome (EGF-L). The animals were sacrificed after 3, 7, 14 and 21 days after surgery. Histological, histomorphometric and immunohistochemistry analysis were performed to evaluate new bone and blood vessels formation as well as the expression of fibronectin and collagen type III, two determinant proteins for early wound regeneration. Our analysis showed a continuous transformation of sockets during all stages of wound healing. Nevertheless, groups BC, L, P and EGF-P followed a regular time for regeneration significantly different from the EGF-L group, which showed faster recovering. A higher expression of fibronectin and type III collagen in the group EGF-L after 3 and 7 days of surgery was observed and might be explained by the ability of the liposome to deliver EGF in a controlled manner, stimulating mesenchymal cells migration and osteoblast differentiation. As liposome efficiently regulated the availability of EGF without risks for its function and protected the factor from early absorption and degradation, the present work indicates that liposomes can be successful used as carriers for controlled delivery of growth factors in bone healing.