To Observve Histomorphology Changes And Study The Dynamic Expression Of OC At The Bone Cement Interface Of Rabbit After Vertebroplasty

Objective: To observve the histomorphology changes and study the dynamic expression of OC at the bone cement interface of rabbit after vertebroplastyMethods: 24 New-Zealand rabbits with osteoporosis were randomly divided into two groups, including experimental group and control group. The experimental group established vertebroplasty model, the control group completed procedure without bone cement injection. Respectively, at 1h, 24h, 3d, 7d, 4w, 12w, rabbits from every group were killed by aeroembolism. The operative vertebral bodies were taken out as research object. The histomorphology changes were observed and the OC expression of rabbit were studied by immunohistochemistry stain at the bone cement interface.Results: At all of the injected sites, there was intimate contact between the cement and the surrounding tissue in experimental group. The volume of PMMA had no prominent changes. There was a 0.5cm low density area in the puncture site in the control group. After taking out the operative vertebra,we observed that PMMA closely integrated with the surrounding tissue. Bone cement volume had no significant change compared with the preoperative. The control group showed normal bone healing process in HE stain. The bone cement closely integrated with bone surrounding tissue in experimental group. There no osteonecrosis between PMMA and surrounding tissue. At 24 hour, inflammatory cell significantly aggregate at the bone cement interface. At 3 day, it's reach to the peak. And at 7 day, it's decreased gradually. At 7 day, a small number of macrophages arrived at the bone cement interface. At 4 week and 12 week, there were no inflammatory cells at the bone cement interface. At 4 week, fibrous tissue surround surface of PMMA bone cement in experimental group. Near the normal tissue, conglomerate cartilage cells grow into. PMMA is still around At 12 week, there were still much fibrous tissue and a large number of lamellar bone formation at the bone cement interface. Compared with normal bone tissue, after 1h, 24h, 3d, the OC expression had no significant increase in both group (P <0.05).At 7 day, the OC expression of control group increased slightly, the PMMA group had no significant change (P>0.05).At 4 week, the OC expression increased in both group, but the control group was more significant than the PMMA group (P> 0.05). The OC expression continued to increase during 4 to 12 week in experimental group. It's slightly decreased in the control group (P> 0.05).Conclusion: There was inflammatory reaction at the bone cement interface. It was delayed compared with the control group. It indicated that the exothermic reaction of PMMA and monomer toxicity did not cause permanent bone necrosis. During the curing process, the OC showed high expression, which delayed compared with control group. This demonstrated that the function of local bone tissue and cell don't suffer irreversible damage.