Intestinal anastomoses from diabetic rats contain supranormal levels of gelatinase activity

Early postoperative strength in intestinal anastomoses is reduced in diabetic rats, whereas collagen deposition is essentially unchanged, suggesting that increased matrix degradation may be the cause of diminished wound strength. The aim of this study was to investigate whether (gelatin-degrading) matrix metalloproteinase activity is enhanced in intestinal anastomoses from diabetic rats. Sixty male young adult Wistar rats underwent resection and anastomosis of both ileum and colon. In half the animals diabetes was induced seven days before operation by streptozotocin injection (50 mg/kg intravenously). Gelatinase activities in extracts from uninjured intestine and anastomoses at one, three, or seven days after surgery were measured by quantitative gelatin zymography. After surgery, profound changes were observed with time for gelatinase activities with molecular weights of 50 and 60 kDa, thought to represent matrix metalloproteinase-2, and of 66, 80, 105, 140, 220, and 260 kDa, thought to represent various forms of matrix metalloproteinase-9. In many cases, specific activities were significantly (P < 0.05) higher in the anastomotic extracts from diabetic rats. Total anastomotic activities present at Day 7 were strongly elevated for most matrix metalloproteinase forms in ileum and colon from diabetic animals. Experimental diabetes leads to a sustained and elevated presence of gelatinase activity in intestinal anastomoses. Increased local matrix degradation may contribute significantly to impaired anastomotic strength in the intestine observed under this condition.