Angiogenesis Change In Gingiva From Patients With Chronic Periodontitis And The Correlated Analysis

BackgroundThe changes of vasculars play an important role in the process of inflammation,which is a series pathological progress of the organism. The development of a vascularsystem at the injury site enables proinflammatory cells to be transported to the lesion,supplying oxygen, nutrients and potential substrate for inflammation. Angiogenesis is aprocess, in which sprouting from established vessels formatted the new blood vessels.Angiogenesis is the expansion and proliferation of blood vessels (mainly the capillaries)that has a relevant role in the development and prognosis of diseases, pathologicalexamination showed the number and diameter changes of vascular.The process of angiogenesis in the inflammation is due to the over expression ofpromoting angiogenesis factors. Under the regulation of cytokines and growth factors,complex interplay of molecular signals were happened, resulting in formation of new blood vessels, with extracellular matrix remodeling, endothelial cell migration andproliferation, capillary differentiation and anastomosis involved. Vascular endothelialgrowth factor (VEGF)，the major angiogenic factor, is the most potent agent that acts onthe vascular endothelium, can direct affects proliferating and migrating endothelial cells,increases microvascular permeability and the differentiation and migration of endothelialcells, and regulates bone homeostasis by recruitment of osteoblasts and osteoclasts.Stromal cell-derived factor-1alpha (SDF-1α) plays important role in survival, growth, andmigration of different cell types, and SDF-1α can interact with VEGF, affecting theprocession of angiogenesis.Chronic periodontitis is caused by anaerobic pathogens and is characterized bychronic inflammation of the tooth supporting tissues, attachment loss, and alveolarbone destruction, which finally results in the loss of teeth. In periodontal tissues,angiogenesis seems to be important for the maintenance of healthy tissues and periodontaldiseases development. However, the relationship between angiogenesis and destruction ofperiondontal tissue in periodontitis, and associated mechanism are still underinvestigation.AimThe present study aims to examine the correlation between the changes ofmicrovessels density and damage of periodontal tissue in chronic periodontitis, andanalyze associated factors.MethodsExperiment1：The expression of microvessels density in gingival tissues of patientswith chronic periodontitisGingival tissues were obtained from patients with chronic periodontitis or periodontalhealthy that according to the inclusion/exclusion criteria. The study protocol wasexplained to each subject, and signed informed consent was obtained. The followingclinical and periodontal parameters were assessed: probing depth (PD) and clinical clinicalattachment loss (CAL). Standardized biopsies were obtained during periodontal surgery for patients with chronic periodontitis or crown length/esthetic surgery for healthy patients.Biopsies were immediately fixed, then dehydrated and embedded in paraffin blocks.Sections were stained with hematoxylin and eosin technique and immunohistochemistry,to examine the expression of CD31in tissues and the changes of MVD in chronicperiodontitis. Statistical analysis was used to detecting the differences of MVD in chronicperiodontitis and healthy controls, and its correlation wih PD and CAL.Experiment2: the expression of angiogenesis factors in gingival tissues of patientswith chronic periodontitisSame specimens as experiment1were used to examine the expression of VEGF andSDF-1α in tissues, The number of VEGF and SDF-1α-positive cells was counted by usinga light microscopeand, then comparise the correlation between VEGF and SDF-1α withclinical parameters PD and CAL. Standardized biopsies were obtained as the same method.To extract RNA and PCR technology were used to analysis the difference of cytokinesCD31，VEGF and SDF-1α between the two groups in gene level.ResultsExperiment1：1. The analyzed of Hematoxylin and eosin showing the epithelium and laminapropria composed of the gingival tissue.Sections in healthy control group can observedepithelial pegs insertion in the lamina propria， with a minimal inflammatoryinfiltrate.Whereas，a large number of inflammatory corpuscle invaded in the submucosa，epithelial pegs hyperplasia and slight hyperkeratosis were observed in the chronicperiodontitis group.2. The results of the immunohistochemical evaluation were showing that CD31wasexpressed at vascular endothelial cells. The CD31-positive vessels mainly locatedin the lamina propria of gingival tissue. Statistical analyses of the results showed, in theexpression of chronic periodontitis group MVD were significantly higher than in healthyperiodontal group(P＜0.05).3. The expression of MVD were significantlly increased with the rise of PD and CAL(P＜0.05), positive linear correlation.Experiment2：1. The immunohistochemical and Real-Time PCR evaluation showed thatangiogenesis factors VEGF and SDF-1α were significantly enhanced in the diseasedgroups compared with the healthy groups(P＜0.05).2. The expression of VEGF and SDF-1α has positive linear correlation with PD andCAL(P＜0.05).ConclusionsIn chronic periodontitis, the microvessels density is positively correlated with thestate of inflammation and the destruction of periodontal tissue. The increasing expressionof VEGF and SDF-1α may be responsible for the increased microvessels density inchronic periodontitis tissues.