Journal of Dental Research, Vol 65, 1449-1452, Copyright © 1986 by International & American Associations for Dental Research Online Journals
Mandibular growth and histologic changes in condylar cartilage of rats intoxicated with vitamin D3 or 1,25(OH)2D3 and pair-fed (undernourished) rats
M. Weinreb Jr, E. Gazit and M. M. Weinreb
The mandibular condyles of 1,25(OH)2D3 or Vitamin D3 intoxicated rats were
studied and compared with those of normal as well as pair-fed controls.
Experimental animals were injected with either Vitamin D3 (2 mg/kg/day) or
1,25(OH)2D3 (400 ng/kg/day) for 19 days. Controls were given the solvent
only, while pair-fed animals were restricted in their food intake for the
same period of time, so that they exhibited a weight-curve similar to that
of the experimental rats. The length of the mandibular ramus was measured
in lateral radiographs of all mandibles. Demineralized coronal sections
were obtained from all mandibular condyles and were stained with Mallory's
connective tissue stain. The width of each zone within the condylar
cartilage was measured. Experimental animals showed significant reduction
in width of all layers within the condylar cartilage, with total lack of
distinction between the maturation and hypertrophic zones. They also
exhibited a significant retardation in growth of the mandible. Pair-fed
animals had a normal width of the chondroprogenitor layer but significantly
smaller maturation + hypertrophic zones (vs. controls). They also exhibited
a significant retardation in mandibular growth but not to the same degree
as did the intoxicated animals. Reduction in growth attributed to
1,25(OH)2D3 or Vitamin D3 intoxication is partly caused by undernutrition,
which is a by-product of this condition. A further kinetic study is
indicated to elucidate the mechanism of growth retardation and the
differential effect on the various cartilage layers.
