Time-course and rate of healing after wounding the avascular mesentery in diabetic rats

The effects of inflicting trauma on the mesentery of diabetic and control rats by perforation with a scalpel were studied with regard to time-course of healing and rate of healing by closure. In this tissue, which is virtually free from blood vessels and nerves, healing precedes vascularization of the wound area. Insulin-deficient rats with streptozotocin diabetes of 4 weeks' duration were used. Non-specific histamine release and cell proliferation (expressed as specific DNA activity) lasting 30 h took place after opening the abdomen and handling the mesentery. Wounding caused further histamine release and cell proliferation. These variables were the same in diabetic and control rats. The time-course of healing was significantly delayed in diabetes, whereas the rate of healing (number of wound closures per day) during the phase of rapid healing was not. Because the rate of healing was normal in diabetic rats the impairment of healing in diabetes can be ascribed to pre-healing reparative events unrelated not only to vascular and neural factors but apparently also to the amount of histamine released and to the cell proliferation elicited by wounding. The delayed healing thus seems to be related to some cellular or metabolic feature of diabetes as yet unknown.