The Bone Regenerative Effect of Calcium Sulfate- chitosan Complex Powder and Chitosan Microsphere Encapsulating Growth Hormone on Bone Formation in Bone Defect of Rabbits

ABSTRACT

This study was carried out on 32 New Zealand white rabbits, each weighing 3-3.5kg. Eight rabbits were allocated into each of four groups. The groups were a control group(I), hyaluronic acid group(II), chitosan microsphere encapsulating growth hormone group(III), calcium sulfate-chitosan powder group(IV). After a 1cm sized ostectomy was made on the tibial body with the periosteum preserved, artificial bone substitutes were implanted. Except group I, 1ml of hyaluronic acid were implanted in group II, 1ml of chitosan microsphere encapsulating growth hormone in group III, 1ml of manufactured calcium sulfate-chitosan complex powder in group IV. Results were evaluated using radiographic study every week, bone mineral density test and histologic examination at 2, 4, 6 weeks and three point bending test at 6 weeks after implantation. In the radiographic study, the formation and corticalization of callus were seen similarly in group III, IV and much more and earlier than group I, II. In the bone mineral density test and three point bending test to contralateral normal tibia in 6 weeks, the values in groups III and IV were statistically significantly higher than in group I and II(p<0.05). In histologic examination, group III and IV have more abundant and faster new boner formation than group I and II. In conclusion, calcium sulfate-chitosan complex powder and chitosan microsphere encapsulating growth hormone facilitates the formation of new bone. They will be used effectively as a bone substitute on defected bone in clinical situations.