Journal of Dental Research, Vol 66, 65-66, Copyright © 1987 by International & American Associations for Dental Research Online Journals
Mandibular growth retardation in growing rats chronically exposed to hypobaria
C. E. Bozzini, R. M. Alippi and A. C. Barcelo
Weanling male Wistar rats aged 21 days were divided into three groups:
initial control, normobaric, and hypobaric (C, N, and H, respectively). C
rats were killed three days after being weaned. H rats were placed into an
altitude chamber and maintained at 456 mb (6100 m) for 14 days. N rats were
maintained at sea-level conditions. Body weight, body and tail lengths, and
food intake were recorded every day. Animals were killed at the end of the
experimental period, and four linear dimensions of the dried mandible were
measured. The amount of food eaten by the H rats during the entire exposure
period was 54.6% of that consumed by N ones. Body weight gain in H rats was
32.7% of that seen in N rats. Body length was 49.0% and tail length was
56.6% of normal. All mandibular dimensions were significantly reduced in H
rats when compared with N rats and were, in general, in close relation with
the reduction observed in skeletal growth. Only one dimension was reduced
out of proportion, which indicates some deformation of the mandible. The
average daily caloric intake related to metabolic body weight (body weight
0.75) of H rats was 60% of the N value. Efficiency of protein utilization
for growth was not significantly different between both groups of rats.
These results indicate that chronic exposure to hypobaria induces overall
skeletal and mandibular growth retardation, which appears to be the result
of a diminution in food intake because of decreased appetite.
