Bmi-1 Deficiency Results In Defects Of Tooth And Mamdible Development In Mice

Objective: To determine the role of Bmi-1 in mouse tooth and mandible development.Methods: The phenotypes of the tooth and mandible were compared between Bmi-1 gene knockout (Bmi-1-/-) mice and their wild-type littermates at 2-4 weeks of age by radiography,micro-CT, histology and histochemistry for total collagen, alkaline phosphotase (ALP), tartrate-resistant acid phosphatase (TRAP).The number of osteoblasts and the positive products of histochemical staining were quantitated by computer-assist image analysis. Results: The mineral density was reduced in teeth and mamdibles, the dental volume, mandiblar bone volume, osteoblast number and ALP positive area were all decreased significantly, however, TRAP positive osteoclast number was not altered in the Bmi-1-/- mice compared to their WT littermates. Conclusion: This study demonstrated that Bmi-1 deficiency led to significant reduction in dental volume and mandible bone volume resulted from decreased dental formation and osteoblastic bone formation. Therefore Bmi-1 gene is essential for the dental and mandible development.