Effects of hyperglycemia and aging in angiogenesis and reepithelization of colonic anastomoses in rats1 Efeitos da hiperglicemia e do envelhecimento sobre a angiogênese e a reepitelização de anastomoses colônicas em ratos

Purpose: To evaluate angiogenesis and reepithelization of colonic anastomoses in rats. Methods: 82 Wistar rats, divided into: young normoglycemic, old normoglycemic and hyperglycemic. Diabetes was induced with streptozotocin. Glycemia was assessed before induction, at 24 hours and after 90 days, when a colotomy and an anastomosis were performed, assessed at days 3, 7, and 14. Samples were prepared by immuno-histochemistry (PCNA and antifactor VIII). Results: Mean glycemia after 90 days streptozotocin induction was 244,95 mg/dl. Day 7, reepithelization was greater in the young group than in the old normoglycemic (p<0.0001) and old hyperglycemic (p<0.0001) groups. Day 14, the differences were significant between the young and old normoglycemic (p<0.0001) and old hyperglycemic (p<0.0001) groups. The two old groups were not significantly different. At the three periods angiogenesis was higher in the young group than in the old normoglycemic (p3=0.014; p7<0.0001; p14<0.0001) or the old hyperglycemic groups (p3=0.014, p7<0.0001; p14<0.0001). The old groups, day 3, were not different (p3=0.627), but days 7 and 14, angiogenesis was bigger in the normoglycemic group (p7=0.042; p14=0.005). Conclusion: Age is important in reepithelization and angiogenesis of colonic anastomoses. Hyperglycemia interferes mainly in angiogenesis.