The Interrelative Study Of VEGF Expression Level And Mandibular Bone Defect Reparation In Experimental Postmenopausal Osteoporosis Rats

ObjectivesTo establish experimental postmenopausal osteoporosis animal model forsecondary mandibular bone defect repairing study. To explore expression levels ofVEGF throughout the bone defect reparation, To study the impact that estrogen onVEGF expression in new formed bone callus, and to discus the function of VEGF inbone defect repairation in mandibula.Materials and Methods80 female Wistar rats were divided randomly into 3 groups: group O(ovariectomy+mandibular bone defect, 27 rats); group E (OVX+mandibular bonedefect+estrogen replacement therapy), in this group nilestriol was given 1.5mg/kg,twice a week Postoperatively. A sham operation group as group S was set up forcomparative study. The serum biochemical indexes were detected before theostectomy and in 1,2,3,4 week time intervals postoperatively, and the specimens wereretrieved for decalcified sections. The expression of VEGF was detected byimmunohistochemical technique. All the results were statistically analyzed.Results1.variety of the bio-chemical index sign in different groups of different timeâ‘ Serous E₂ level: preoperatively, group O and group E is lower than group E, Thedifference was statistically significant (P=0.000, P=0.000); 1 week postoperatively,there were differences between every two groups, group S is the highest, then group E,the lowest is group O; Through 2 to 4 weeks, there were no difference between groupS and E, that both in a higher level than O, The difference was statistically significant(P＜0.05)。 â‘¡Serous ALP level: preoperatively,there was no difference between group O and E(P=0.967),that both in higher level than group S (P=0.000, P=0.000);1 weekpostoperatively, there were no significant difference; in 2 weeks time interval, groupS and O were no significant difference (P=0.830),but both higher than group E(P=0.003, P=0.002); in 3 to 4 weeks, there were differences between each twogroups, group O is the highest, followed by group S, the lowest is group E.2. VEGF immunohistochemistry1 week postoperatively: there were no significant difference between group O and E(P=0.076),and both higher than group S (P=0.000, P=0.001); there weredifferences between each two groups in 2 weeks, group O is the highest, then group S,the lowest is group E. (P＜0.05); through 3 to 4 weeks, group S and E were in nosignificant difference, but both higher than group O (P＜0.05).Conclusions1.OVX made fiber bone callus period longer in bone defect repair, which means OPaffect the early healing of rat's mandibula bone defect.2.Expression of VEGF in group O was higher than group S and E throughout thewhole study period and the difference was statistically significant, suggested that thatOVX makes VEGF a high durative expression in bone callus, and had a differentdegree and different cells involved in different period, and simultaneously, suggestedthat VEGF can help the propagatation of endothelial cells and formation of vessals,it played an important role in the defect reparing of bone.3. There was no difference of E₂ expression level between group E and S, impliedthat nylestriol works in prevention and therapy of osteoporosis, and helps with defectrepairation of steoporosis rat's mandibula.