Abstract: Objective This study took the radicular cyst as the model,determined the rate of bone destruction on the basis of the clinical characteristics,measured the microvessel density in interstitium by immunohistochemistry;The fibroblasts were isolated from capsule,through which the association of various VEGF isoforms with microangiogenesis and osteoclastogenesis were analyzed to investigate the role of the alternative splicing of VEGF in the process of bone destruction of odontogenic cysts. Methods We selected 19 cases of periapical cysts.The immunohistochemical staining with CD34 antibody was used to stain vascular endothelial cells,and the area of the vascular cavity was calculated.The lesion area was measured by the dental panoramic tomography.Thirteen cases of fresh specimens were prepared to culture the apical cystic fibroblasts.We prepared conditioned medium and induced osteoclasts,and extracted RNA to detect the relative expression of VEGF isoforms by real time PCR.The Chi-square test was used to assess CD34-positive vascular lumen area and clinical features.Logistic regression and Spearman's rank correlation were used to analyze the relations between vascular lumen area,the relative expression of various isomers,the rate of cyst progression and the osteoporosis induction efficiency. Results The ratio of VEGF-121a/total VEGF and VEGF-165a/total VEGF were positively associated the area of microvessels,and the area of microvessels was positively associated with bone destruction of odontogenic cysts;On the other hand,the relative quantitative expression of VEGF and VEGF-189a were positively associated with osteoclastogenesis,however,VEGF-165b/total VEGF and VEGF-189b/total VEGF were negatively associated with osteoclastogenesis. Conclusion VEGF-xxxa isoforms may promote the bone destruction,while VEGF-xxxb variants may play an inhibitory effects.