Journal of Dental Research, Vol 63, 23-27, Copyright © 1984 by International & American Associations for Dental Research Online Journals
Extensive degradation of recently synthesized collagen in gingiva of normal and streptozotocin-induced diabetic rats
M. L. Schneir, N. S. Ramamurthy and L. M. Golub
The degradation of recently synthesized collagen (probably procollagen) in
rat incisor gingiva was three times greater than that in skin.
Concomitantly, the formation of undegraded (intact) collagen molecules in
gingiva was slower than that in skin. This high basal rate of degradation
in gingiva was just slightly increased in streptozotocin-induced diabetic
rats, whereas the low basal rate in skin was dramatically increased by the
diabetic state. The degradation of recently synthesized collagen was
measured by the relative amounts(%) of [3H]hydroxyproline-containing
material in the TCA-soluble fraction of a tissue, compared with the total
amount (TCA-soluble + TCA-insoluble) of [3H]hydroxyproline-containing
material. Separation of the TCA fractions allowed the formation of collagen
degradation products (TCA-soluble) to be viewed separately from the
formation of undegraded collagen molecules (TCA-insoluble). The
[3H]hydroxyproline-containing material in the TCA-soluble fraction was
greatest in amount and in specific activity, 30 min after [3H] proline
injection, supporting the origin of this material as being procollagen. At
this time period, the relative amounts of TCA-soluble
[3H]hydroxyproline-containing material were 40.3% (gingiva) and 12.7%
(skin). For diabetic rats, the values were 55% and 48.8%, respectively. For
the [3H]hydroxyproline-containing material in the TCA-insoluble fraction,
at 30 min, the specific activity of [3H]hydroxyproline was 4.3 for gingiva
and 7.4 for skin. At all other time periods, the values were also greater
for skin than for gingiva, making it unlikely that the formation of intact
collagen molecules occurred faster in gingiva than in skin.(ABSTRACT
TRUNCATED AT 250 WORDS)
