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

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.

Wound Healing Effect of the Chitosan Sponges Containing the T-CAM or Regenin

Tetra cell adhesion molecule(T-CAM) is a new recombinant mixture of fibronectin and ig-h3. Fibronectin and ig-h3 are extracellular matriprotein involved in each phase of wound healing, and the combination of these materials may generate a synergistic effect in wound healing. Regenin is easily attainable from protein recombination. It can be developed as wound healing material, and also it has a good effect in cell adhesion and proliferation. We combined the chitosan with regenin or T-CAM at different concentration, which are gene recombination material. They were applied to the artificial wound of white rabbit to compare the healing effect in each group. Round full thickness skin defects, 3 cm in diameter, were made bilaterally on the dorsolateral aspect of New Zealand white rabbit. Experimental group was divided into 6 groups, according to concentration of T-CAM and regenin with chitosan-based dressing materials as followings; Group C: control group - oint material dressing, Group Ch: chitosan base only, Group T1: chitosan base in combination with 25 microgram/ml of T-CAM, Group T2: chitosan base in combination with 625 microgram/ml of T-CAM, Group R1: chitosan base in combination with 25 microgram/ml of Regenin, Group R2: chitosan base in combination with 625 microgram/ml of Regenin. Gross findings by means of percentage of wound contraction, percentage of wound epithelization and percentage of total wound healed area were compared with surface tracing of the remained wound area at the time of 7, 14, 21 days after wound formation. Wound biopsy were performed at the time of 7, 14, 21 days after wound formation. T1, T2 group and R1, R2 groups have less infiltration of inflammtory cell, fast appearance of new vessels, fibroblast, increased volume of collagen fiber comparing to C and Ch group. there's more statistical significance between T1 and T2 group. The same results were shown in Regenin group. In conclusion, our results suggest that T-CAM and Regenin have good effect in wound healing and higher concentration of T-CAM and Regenin is more effective in wound healing than lower concentration. In addition, comparision of same concentration of T-CAM and Regenin group presented almost same results.

Comparison of Wound Healing Effect of Different Forms of Chitosan

This study is to compare the effect of wound healing using three different types of chitin, which include the shapes of sponge, velvet, thick non-woven fabrics, and thin non-woven fabrics. The sponge type had more capacity to absorb the first discharge of a wound than the velvet type and the two non-woven fabrics types. Instead of absorbing the discharge effectively, the velvet type showed a difficulty to take off the dressing stuff from a wound since it was solidly stuck to the wound. The sponge type showed less infiltration of inflammatory cells, producing angiogenesis and fibroblast faster than any other types. Next, the thick non-woven fabrics type was a little more effective than the thin non-woven fabrics type: However, there was no difference between two types. The velvet type sustained the infiltration of inflammatory cells for the longest duration, producing slower angiogenesis and fibroblast. In wound contraction and wound healing, the sponge type was most effective with statistical significance than any other types(p0.05). In conclusion, the sponge type showed the best effectiveness to absorb the early discharge, facilitating the progress of inflammatory phase to increase the healing rate. It induced an early healing of wound caused by wound contraction rather than by wound epithelization.

Effect of Injectable Chitosan Bead Encapsulating Calcium Sulfate on Bony Consolidation in Distraction Osteogenesis

The purpose of this project was to study the effect of injectable chitosan bead encapsulating calcium sulfate, which makes sustained release of chitosan and calcium sulfate after implantation, on early bony consolidation in distraction osteogenesis of a dog model. Forty five dogs were used for this study. An external distraction device was applied to the mandibular body after vertical osteotomy and the mandibular distraction was started five days after the operation at a rate of 1mm per day up to a 10mm distraction. The experimental group was divided into a control group(I), hyaluronic acid group(II), chitosan group(III), calcium sulfate group(IV), and injectable chitosan bead encapsulating calcium sulfate group(V). Normal saline was injected in the group I. In the group II, a 1-ml volume of hyaluronic acid solution was injected into the distracted area. In the group III, a 1-ml of injectable solution of chitosan mixed with hyaluronic acid was implanted. In the group IV, a 1-ml of injectable solution of calcium sulfate mixed with hyaluronic acid was implanted. In the group V, injectable form of powders of chitosan bead encapsulating calcium sulfate mixed with a 1-ml volume of hyaluronic acid was implanted. Bone mineral density was measured in each group at third and sixth week. The mean three point failure load was measured in each group. In histological findings, new bone was generated in all groups. In the group IV and V, the formation of active woven bone was observed throughout the distracted area at sixth week. The amount of new bone formation in the distracted zone was in the order of the group IV and V, group III and group II, and control group. In conclusion, these findings suggest that injectable chitosan bead encapsulating calcium sulfate appears to be effective in early bony consolidation in distraction osteogenesis.

Effect of Calcium Sulfate-Chitosan Composite Pellet on Bone Formation in Bone Defect of Rabbits

This study was carried out on 80 New Zealand white rabbits, each weighing 3-3.5kg. Twenty rabbits were allocated into each of the four groups. After a 1cm sized ostectomy was made on the tibial body with the periosteum preserved, artificial bone substitutes were implanted. Except for control group(I), manufactured chitosan pellets were implanted in group II, Osteoset(R)(calcium sulfate) in group III and manufactured calcium sulfate-chitosan composite pellets in group IV. Results were evaluated using radiographic study, bone mineral density test and histologic examination in 2, 4, 6 weeks and three point bending test in 6 weeks after implantation. In the radiographic study, the formation and corticalization of callus were similar in groups III, IV and this was much earlier than in groups 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 groups I and II(p<0.05). In histologic examination, groups III and IV have more abundant and faster new bone formation than groups I and II. In conclusion, the synergistic effect between calcium sulfate and chitosan in group IV is considered to facilitate new bone formation as effectively as Osteoset(R) does.