Journal of Dental Research, Vol 70, 99-101, Copyright © 1991 by International & American Associations for Dental Research Online Journals
A human periodontal ligament fibroblast clone releases a bone resorption inhibition factor in vitro
M. S. Giniger, L. Norton, S. Sousa, J. A. Lorenzo and F. Bronner
Department of BioStructure and Function, University of Connecticut Health Center, Farmington 06030.
The conditioned media (CM) obtained from three lines of cloned human
periodontal ligament (PDL) cells were analyzed to determine whether they
altered the parathyroid hormone (PTH)-stimulated resorption rates (45Ca
release) in 48-hour cultures of 45Ca-labeled rat long bones. One PDL cell
line, PDL-5, produced a heat-resistant factor in its CM that inhibited the
PTH-stimulated resorption by 43.8 +/- 9.7 (SE) percent (p less than or
equal to 0.02), whereas the CM from the other cell lines were without
statistically significant effect. The CM from the PDL-5 line did not
diminish organ culture viability, as determined by 3H-thymidine
incorporation, and did not enhance or diminish the resorption-inhibiting
activity of calcitonin added to the PTH-stimulated cultures. The addition
of CM from PDL-5 did not alter the bone-resorbing effect of interleukin-1
(IL-1). These results indicate that CM from PDL-5 inhibits only the
PTH-induced and not the IL-1-mediated resorption processes, whose
mechanisms are therefore likely to differ.
