Epidermal growth factor and insulin act synergistically during diabetic healing
P. J. Hennessey, C. T. Black and R. J. Andrassy
Department of Surgery, University of Texas Medical School, Houston.
Increased wound collagen catabolism is among the defects of diabetic wound
repair. We studied the interactions of topically applied insulin and
epidermal growth factor (EGF) in diabetic rats. Polytetrafluoroethylene
cylinders were implanted in 80 diabetic rats and removed on postoperative
days 1, 5, 10, and 15. Cylinders were analyzed for collagen concentration
and collagenase activity. The EGF and insulin promoted a 202% increase over
controls in collagen synthesis by day 15, while diabetic rats that received
EGF or insulin alone had significantly less collagen than controls. All
groups that received insulin had lower collagenase activity than both
controls and diabetic rats that received EGF. The individual effects of
insulin and EGF added synergistically for a net gain in wound collagen
content after 15 days. This gain was not observed with either EGF or
insulin alone.
