Journal of Dental Research, Vol 68, 1058-1063, Copyright © 1989 by International & American Associations for Dental Research Online Journals
The effect of sutural growth rate on collagen phenotype synthesis
E. H. Yen, C. S. Yue and D. M. Suga
Orthodontic Section, Faculty of Dentistry, University of Manitoba, Winnipeg, Canada.
We determined the ratio of newly-synthesized type III collagen to the total
of type I and type III collagen in mouse interparietal sutural tissue at
selected ages between birth and adulthood (36 weeks old). We incubated
mouse calvaria explants in Trowell-type organ culture dishes for one h and
then added [14C]-glycine for two h. We dissected the interparietal sutural
tissues for collagen solubilization by limited pepsin digestion.
Fluorographic visualization of separated radiolabeled collagens, after
SDS-PAGE, found the ratio of collagen type III alpha-chains to the total
type I and type III alpha-chains to be age-dependent. The proportion of
type III alpha-chains at birth was quite high, but there was a significant
drop (p less than 0.05) during the first two days of life, probably because
of the sudden environmental change from in utero. The proportion of type
III alpha-chains rose significantly from day 2 to day 4, reaching a maximum
and then dropping significantly to about the same proportion as at birth by
day 7. A further significant drop took place during the second week of
life, with the proportion stabilized at around 3.5% at two weeks to ten
weeks of age. A final significant drop during the eleventh week of life led
to no detectable synthesis of type III collagen after 12 weeks of age. The
changes in the collagen phenotype ratio did not relate to changes in body
weight during growth and development, which suggests that the interparietal
suture may have an independent maturing pattern.(ABSTRACT TRUNCATED AT 250
WORDS)
