TGF-BETA-1 IS ESSENTIAL FOR THE HOMEOSTASIS OF THE DENTIN-PULP COMPLEX

Among the complex network of cytokines that influence odontoblast func tion during development and repair. TGF-beta 1 is unique in its dual a bilities to function as a potent immunosuppressant and as an inducer o f extracellular matrix production. These properties underscore the imp ortance of this molecule in maintaining the homeostasis of the dentin- pulp complex after injury. The purpose of this paper is to describe ne w findings of our phenotypic analysis of dentition in mice in which th e TGF-beta 1 gene has been disrupted. The major phenotype of TGF-beta 1(-/-) offspring is one of diffuse immune system activation with progr essive inflammation; wasting and death. Our studies elf adult TGF-beta 1(-/-) dentition show widespread pulpal and periapical inflammation a nd necroses. In addition, the coronal surfaces of occluding molars sho w marked attrition. To determine whether the phenotypic changes in TGF -beta 1(-/-) dentition are directly linked to the loss of TGF-beta 1 r ather than the inflammatory process itself, we studied adult dentition in TGF-beta 1(-/-) mice backcrossed into immunodeficient backgrounds. Results of our histopathologic and radiographic analyses show that te eth of TGF-beta 1(-/-) immunodeficient mice retain vitality in pulpal and periapical regions but show excessive wear of occlusal surfaces.