A Study On Expression Of VEGF Within The Periodontium Of OVX Rats With Experimental Periodontitis

Vascular endothelial growth factor (VEGF) has an ability to induce functional osteoclasts as well as angiogenesis.Objective: To investigate the effects of estrogen deficient on host susceptibility with periodontitis, immunohistochemistry methods were used to semi-quantitative analysis the expression of VEGF in the periodontium for bilateral ovariectomy SD rats co-treated with experimental periodontitis at the same time. Trying to elucidate the mechanism of alveolar bone resorption in periodontitis with the network of synergistic cytokines action.Methods: 53 six-months-old SD rats were randomly divided into 3 groups: sham operation group(Group A,n=17),ovariectomized group(Group B,n=18)and ovariectomized plus estradiol₂ administration(Group C,n=18).2 and 4 weeks after ovariectomy (or sham operation), orthodontic wire were used to ligature the cervix of each first molar and then feed with high glucose softy foods to cause experimental periodontitis. Every rats were sacrificed 4 weeks after experimental periodontitis. Probing pocket depth (PPD) were measured and blood samples were collected in order to obtain Serum concentration of Calcium , Phosphorus(P)and alkaline phoshatase (ALP) before sacrifice. Two registration of periodontal bone destruction methods were used with slight modifications. Maxillary specimen radiographs were taken with X-ray machine to measure periodontal bone support (PBS). Periodontal bone loss (PBL) were evaluated morphometrically by measuring the distance between cemento-enamel junction and buccal alveolar bone crest. Immunohistochemistry were used to evaluate express of VEGF in periodontium, computer image analysis system were used for semi-quantitative analysis.Results: The alkaline phosphatase level(U/l) was higher in ovariectomy group than in sham operation group or estradiol group(P<0.01) and therefore confirmed a high bone turnover in the rats which were in the estrogen- deficient state (98.200±l9.708 , 119.322±18.755 , 84.750±9.499 ; 80.675±13.864 , 142.867±53.683 , 64.150±21.623 for groups Al, Bl, Cl ; A2, B2 and C2,respectively)o There were no difference between all the groups or stage with the calcium serum level(P>0.05).And the mean calcium serum levels (mmol/l)were 2.500±0.180, 2.422±0.164, 2.488±0.164, 2.725±0.315, 2.467±0.141 and 2.600±0.200.The mean phosphorus serum level(mmol/l) was higher in ovariectomy group than in sham operation group or estradiol group(P<0.05 between groups ovariectomy for 8 weeks and P<0.01 between groups ovariectomy for 6 weeks)with the concentrate of 1.887±0.447, 2.636±0.511, 2.069±0.547; 1.853±0.281, 2.248±0.304 and 1.802±0.298 respectively.There was significantly difference of mean probing pocket depth (PPD) between ovariectomy group and sham operation group which under the operations for six weeks(P<0.06).But no statistical difference between other groups or between each stage of every group. The mean PPD were 0.844±0.401, 1.111± 0.314, 0.956±0.251, 0.613±0.064, 0.906±0.269 and 0.745±0.263 respectively.Ovariectomy caused significantly more horizontal periodontal bone loss (PO.01) with the mean PBL of 0.276±0.011, 0.472±0.014, 0.286±0.010; 0.245 ±0.024, 0.451 ±0.021 and 0.245 ± 0.024 for each group respectively. Meanwhile significantly less periodontal bone support(PBS) than the others group at the same ovariectomy period were found in ovariectomy groups. The mean PBS percentage of each group were 44.044±1.966, 38.000±7.050, 45.638±2.230; 46.675±9.117, 34.733±6.571 and 50.260±l 1.Irrespectively.Immunohistochemistry showed that VEGF expressed in every 3 group with different degree. High expression of VEGF in ovariectomy groups compared with the other two groups about relatively wild positive expression. VEGF mostly...