Cytoplasmic polarization of periodontal ligament fibroblasts

Abstract

The fibroblasts of the periodontal ligament and especially those of the transseptal ligament are characteristically elongated with their long axes parallel to the principal fiber bundles. Their cytoplasmic orgamelles are polarized suggesting that secretory products are released from one end of the cell. The nucleus occupies the anterior pole of the cell. Cytoplasmic processes or lobopodia, containing numerous cytoplasmic filaments, extend from the anterior pole of the cell. The Golgi complex is situated in a large area of the cell between the nucleus and the distal end of the cell. Granular endoplasmic reticulum, mitochondria and numerous small vesicles are dispersed throughout most part of the cell. Intracellular collagen, akthough present in many areas of the cell, appears to be most abundant in the distal parts of the cell. Administration of colchicine in vivo, blocked collagen secretion and dereased cell elongation and polartity. Results of and analysis of the orientation and polarization of the fibroblasts in the periodontal tissues appear to support the concept that these cells undergo active migration in vivo along existing substrata and that migration may be coupled to collagen secretion.