Mandible Bone Repair In Rabbits With Chitosan/n-HA Composites

Objective: Hydroxyapatite (HA) is a widely used material in clinical bioactive. Chitosan is derived from Chitin and it is not dissolved in water, but soluble in acid. Furthermore, it can be absorbed into the human body. To observe the heal process of Chitosan/HA composites restore the rabbits jaw bones. Following observations and evaluations were carried out of optimizing composites for bone regeneration. The mainly purpose of this experiment was to give a preliminary experimental evidence and to prove the novel composites as potential bone substitutions or bone tissue engineering scaffold.Methods: 1. Preparation of materials: The Hydroxyapatite (HA) were provided by National Hepatobiliary & Enteric Surgery Research Center- National Key Laboratory of Nanobiological Technology. Chitosan was purchased from Sigma-Aldrich. The Chitosan/HA composites was prepared in our laboratory. After preparation, the physical and chemical properties of the composites were preliminary studied.2. Animal experiments: 30 adult rabbits were divided into 3 time groups randomly: A: Chitosan/HA group; B: HA group; C: post-operative group. After2, 4, 6 and 10 weeks post-operation, the experimental rabbits analyzed by radiographic, following, the animals of every group were killed according to different operalion period and the implantations were taken off and studied by gross observation,X-ray density,histological analysis and X-ray gray extent of callus analysis.Results: (1) After 10 weeks post-operation , the Chitosan/HA composites group can restore the wane completely, and every period X-ray estimate all good than the others, and it have an exponential correlation(P<0.05). (2)at 12th week HA group restore effect is worst than A group(P<0.05). (3) The bending strength of callus and the X-ray density of callus have an exponential correlation(P<0.05).The X-ray density of callus increased coincidently with the fracture healing process. It also confirmed that there was a high correlation between the character of bending strength of callus and the X-ray density of callus.Conclusions: The Chitosan/HA composites have a good biocompatibility and has some power of bone guide, it can replace homograft bone, and they were suitable for the growth of osteoblasts as well as reformation of new bone tissues.