| Abstract:Objective:To study the role of PRP in the promotion of bone repair and the local vascularization. Method:12 New Zealand white rabbits were used, created bone defect models in both sides of the mandibular angle,so twenty-four parts of bone defects are obtained in all. The rabbits can be divided into three groups by different materials:Group A (experimental group)、Group B(control group) and Group C (Blank group). In according to the time, the rabbits can be divided into three groups:2 weeks group、4 weeks group and 8 weeks group. In the light of the experimental procedures, it can be divided into three parts:Part I:Preparation of PRP. Autologous arterial blood were collected through anticoagulation treatment, to acquired the PRP, got a portion of the blood to took twice centrifugation, then PRP and whole blood fully mixed with artificial scaffold and blood dotting agent respectively. Count the number of platelets in PRP and whole blood samples respectively. Part II:Preparation of trauma model and artificial scaffold transplantation. Established the trauma model of bone defect in the lower edge of mandibular angle of each rabbits, implanted corresponding artificial scaffold in the bone defects (experimental group:PRP+scaffold; control group:whole blood+scaffold; blank group:not any material). Part III:Specimen acquired and analysis.2 weeks、4weeks and 8weeks later after the surgery, kill the rabbits, took out the mandibulars, observed them generally, then took X-ray inspection and got photos, HE staining. Observated the process of new bone formation and the process of vascularization. Through IPP5.0 software, calculated the area of vascular, accessed the data, used statistical methods to analyzed the results. Results: 1.After the twice centrifugation, compared with the platelates in whole blood,the platelets in PRP has its statistics significance.2.1n the manufacturing process of bone defect model in the body of mandiblular, the trauma area could not be too large, because it is easy to fracture during the surgery or after it, and the post-operative care would be a big problem,so it was reasonable to took the model at the mandibular angle, and the experiments had demonstrated it.3.2 weeks later after the surgery, there was no obvious reduction in the defect area in each group, X-ray showed that there was no new bone formation, but HE staining in the experimental group and control group had a small amount of vessels and osteoblasts, and the the experimental group was more than the control group, blank group had no neovascularization.4 weeks later, the area of bone defects had little smaller than before in experimental group and control group, while the blank group had slow healing relatively. X-ray showed:the defect edge of the experimental group and control group had low density new bone formation, blank group had no significant new bone formation, HE staining showed:the experimental group and control group showed a large number of bone tissue and angiogenesis, and the experimental group was more than the control group, experimental group also had the original trabecular bone formation, the osteoblasts and vascular proliferation activity, the blank group only had little fiber connective tissue proliferation. At 8 weeks after the surgery, the area of bone defect almost be repaired in the experimental group and control group, the experimental group is more like the nomal bone appaearance, the defect of the blank group just a little smaller than the original bone defect area. By X-ray, the experimental group and the control group had a large number of low-density new bone formation, but the bone density was lower than normal bone, HE staining showed:in the experimental group, the bone tissue proliferated actively and differentiated into regular trabecular bone gradually. the morphogenetic of bone matured, a large number of new trabeculae bone formated in the experimental group. At this time the experimental group had less vascular than its number at 4 weeeks, it also less than the control group at 8 weeks. Blank group showed much fibrous connective tissue and osteoblasts.Conclution:PRP has a significant advangtage in the repair of bone defect, it can promote the local vascularization and new bone formation、differentiation and maturation. obviously, because the blood extracted for PRP from oneself, the extraction is little trauma, the body can completely afford it, thus it is worth while us to waiting its clinical application. |
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