抗感染重组合异种骨系列实验研究

目的：研制和开发能I期植骨、有效修复污染性或感染性骨缺损的植骨材料。方法：在重组合异种骨（RBX）的基础上,结合抗生素局部缓释技术,研制抗感染重组合异种骨（ARBX）,并通过小鼠股部肌袋模型检测其诱导成骨活性和抗生素释放特性;将其I期植入细菌污染的犬桡骨骨缺损和已感染的兔胫骨骨缺损中,通过放射学、组织学、细菌学检测手段,评价其对污染性或感染性骨缺损的修复效果,以及对骨髓炎的防治作用。结果：（1）ARBX既保持高效诱导成骨活性,又有较好的抗生素缓释作用,在局部可维持长达30d的有效抗菌浓度,因此具有显著增强的抗感染能力;（2）ARBX在彻底清创基础上,可I期植骨修复细菌污染的犬桡骨骨缺损,并有效预防骨髓炎发生;（3）在彻底病灶清除前提下,ARBX可I期植骨修复已感染的兔胫骨骨缺损,并能有效治疗慢性骨髓炎。结论：ARBX具有高效诱导成骨活性和强力抗感染能力,能I期植骨修复污染或感染的骨缺损,并可有效防治骨髓炎。为ARBX应用临床,解决污染或感染骨缺损治疗上的难题,提供较好的实验基础。

Experimental study of anti-infective reconstructed bone xenograft

Objective To develop a new type bone graft material that can be used as primary graft in contaminated even infected bone defect. Methods Anti-infective reconstructed bone xenograft (ARBX) was developed by combining reconstructed bone xenograft (RBX) with gentamycin and gelatin. One piece of ARBX was implanted in the muscle pouch in right thighs of 32 mice. The implanted ARBX and surrounding soft tissues were taken out from the mice at different time point to make into homogenate and the concentration of released gentamycin in the supernatant and the diameter of the bacterial inhibition ring of each specimen were tested. One piece of ARBX was implanted into the muscle pouch at the right thigh of 16 mice and one piece of RBX was implanted into the muscle pouch at the right thigh of another 16 mice. Fourteen days after the grafts and surrounding tissues were taken out to be examined histologically or made into homogenate to test the alkaline phophatase (ALP) activity. Bone defect was made in the bilateral radii and then Staphylococcus aureus was injected and debridement was conducted. 10 pieces of ARBX were implanted into the bone defect at the left radius and 10 pieces of RBX were implanted into the bone defect at the right radius. The defect was then fixed and the wound was sutured. Gentamycin was injected for 1 week. Six months later X ray examination was conducted to the radius, then the radius was taken and half of specimens were examined histologically and half of them was made into homogenate to examine the amount of Staphylococcus aureus. Defect was made in the right tibia of 25 rabbits and Staphylococcus aureus injected therein. Then the rabbits were divided into 5 groups of 5 individuals: group 1 (3 pieces of ARBX were implanted), group 2 (3 pieces of RBX were implanted and gentamycin was used locally), group 4 (3 pieces of RBX were implanted and gentamycin was injected intramuscularly), and group 5 (control group, without born grafting). Eight weeks after, radiological, histological, and bacteriological methods were used to observe the recovery of bone defect and amount of Staphylococcus aureus. Results Gentamycin was released slowly from the ARBX and the effective bacterium-inhibiting concentration lasted 30 days. There was no significant difference in osteoinductive activity and related ALP activity between the mice implanted with ARBX and RBX. The bone defect of the dogs implanted with ARBX recovered better than that of the dogs implanted with RBX; osteomyelitis was found in the specimens from the bone defect implanted with RBX and not in the specimens implanted with ARBX, and the positive rate of Staphylococcus aureus was lower in the specimens implanted with ARBX than in the specimens implanted with RBX. 8 weeks after the implantation the Norden score of osteomyelitis was the lowest in the rabbits of group 1 (P<0.01). The bone defect recovered better in the rabbits of groups 1 and 2. The number of Staphylococcus aureus in the bone defect in rabbits of group 1 was significantly smaller than that in the rabbits of group 2 (P<0.05), and was very significantly smaller then in the rabbits of the other 3 groups (P<0.01). Conclusion ARBX has strong oeteoinductive and anti-infective abilities. It can be used in primary bone grafting to treat contaminated even infected bone defect.