Diabetes, Vol 37, Issue 4 371-376, Copyright © 1988 by American Diabetes Association
Decreased collagen production in diabetic rats
RG Spanheimer, GE Umpierrez and V Stumpf
Department of Medicine, Emory University School of Medicine, Atlanta, GA 30303.
Many of the chronic complications of diabetes mellitus involve defects in
the connective tissue such as poor wound healing, diminished bone
formation, and decreased linear growth. Because collagen is the major
protein component of these connective tissues, we examined collagen
production in diabetic rats as a probe of this generalized defect in
connective tissue metabolism. Doses of streptozocin ranging from 35 to 300
mg/kg were used to induce diabetes of graded metabolic severity in rats.
Parietal bone or articular cartilage was removed and incubated at 37
degrees C with 5 microCi L-[5-3H]proline for 2 h, and collagen and
noncollagen protein production were quantitated after separation with
purified bacterial collagenase. Within 2 wk after induction of diabetes,
collagen production was significantly reduced in bone and cartilage from
diabetic rats to 52% (P less than .01) and 51% (P less than .01) of control
(buffer-injected) levels, respectively. In contrast, noncollagen protein
production in bone and cartilage from diabetic animals was no different
from in tissue from control rats. The correlation between collagen relative
to total protein production (relative rate) and the degree of hyperglycemia
was highly significant for both bone (r = -.77, P less than .001) and
cartilage (r = -.87, P less than .001). Other factors found to correlate
with altered collagen production were the duration of diabetes and the
amount of weight loss. Thus, diabetes is associated with a marked decrease
in collagen production, which was seen early after induction of diabetes
and was specific when compared with noncollagen protein production.
Cumulative effects of these marked changes in collagen production may
contribute to the chronic connective tissue complications in diabetes.