Growth factors bFGF and TGB beta accelerate the rate of wound repair in normal and in diabetic rats

The effects of basic fibroblast growth factor (bFGF) and transforming growth factor beta (TGF beta) on the rate of wound repair in both normal and streptozotocin-induced diabetic rats were investigated using two model systems of wound repair, namely incisional wounding and subcutaneous implantation of polyvinyl alcohol (PVA) sponges. Both models showed the expected wound-healing defects of the diabetic rats. Granulation tissue collected from the implanted PVA sponges showed that the diabetic rats had reduced amounts of collagen, DNA and protein present at the wound site at two time points tested (7 and 9 days post-implantation). Fresh tensile strength of the incisional wounds, a measure of the collagen organization in a wound, was reduced to 53% of normal in diabetic rats on day 7 post-wounding, and was only 29% of normal by day 21. Formalin-fixed tensile strength, a measure of collagen content of the wound, was 41% of normal on day 7, and 78% of normal by day 21, giving evidence that while the collagen concentration of the diabetic wounds approached that of normal wounds, it did not undergo the normal maturation process. A single injection of 2 micrograms of TGF beta directly into the incision three days after wounding resulted in little difference in the fresh and fixed tensile strength of diabetic wounds when tested at 7, 14 and 21 days post-wounding. Normal rats, however, responded well, resulting in a greater than 30% increase in both fresh and fixed tensile strength.(ABSTRACT TRUNCATED AT 250 WORDS)