Endoneurial microvasculature of chronically transected sciatic nerves in diabetic rats

To characterize the morphology of the endoneurial microvasculature of degen erating nerves under hyperglycemia, the morphology of endoneurial microvess els in transected sciatic nerves was examined in normal and streptozotocin- induced diabetic rats. Three months after transection, the fascicular area and median vascular luminal area at the proximal level of the distal stump were significantly larger in diabetic than in control animals, whereas the number of vessels per fascicle was the same in the two groups. Arterioles i n various stages of development were found in the centrifas-cicular region in some transected nerves. Serial sections I revealed that these vessels or iginated from transperineural arterioles. The frequency and magnitude of va scular wall thickening were both greater in diabetic rats. These results su ggest that the endoneurial microvasculature responds abnormally to nerve in jury under hyperglycemia.