The high concentration of glycosylated extracellular
proteins found in diabetics may contribute adversely to wound healing. The degree of
collagen glycosylation was correlated with
collagenase activity and 5-hydroxyproline (5-OHP) levels in
surgical wounds of normal and diabetic animals. Expanded
polytetrafluoroethylene (
PTFE)
wound cylinders were implanted subcutaneously in 10 normal and 10
streptozotocin-induced diabetic rats. Nonenzymatic glycosylation (NEG) of
protein was inhibited in half the subjects in each group by daily enteral
acetylsalicylic acid (ASA).
Wound cylinders were removed on the fifth day and assayed for
collagenase activity and 5-OHP levels, and the degree of
collagen glycosylation was measured with an assay for
5-hydroxymethylfurfural (5-HMF). Results were compared using Student's two-tailed t test. When compared with controls, diabetic animals had less
wound 5-OHP (1.87 +/- 0.01 vs 3.11 +/- 0.03 micrograms/cm
PTFE) (P less than 0.0001), higher levels of
glycosylated collagen (215 +/- 11 vs 150 +/- 9 micrograms 5-HMF/mg
protein) (P less than 0.001), and increased
collagenase activity (13.5 +/- 0.6 vs 11.7 +/- 0.5 microgram
collagen/mg
protein/hr) (P less than 0.001). When ASA was added to the diet of diabetic animals, results in each case were statistically indistinguishable from controls. The
collagenase activity of nondiabetic animals receiving ASA was decreased from nondiabetic controls (7.6 +/- 0.5 vs 11.7 +/- 0.5 microgram
collagen/mg
protein/hr) (P less than 0.001). These data show that ASA inhibits NEG of
wound collagen in vivo, and ASA may normalize some abnormalities of wound healing found in diabetic animals.