抄録
To characterize the morphology of the endoneurial microvasculature of degenerating nerves under hyperglycemia, the morphology of endoneurial microvessels in transected sciatic nerves was examined in normal and streptozotocin-induced diabetic rats. Three months after transaction, 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 in various stages of development were found in the centrifascicular region in some transected nerves. Several sections revealed that these vessels originated from transperineural arterioles. The frequency and magnitude of vascular wall thickening were both greater in diabetic rats. These results suggest that the endoneurial microvasculature responds abnormally to nerve injury under hyperglycemia. In this study, we examined the effects of experimental diabetics on the structure of microvessels in isolated distal stumps of the transected sciatic nerve. First, endoneurial microvessels were significantly more dilated in diabetic rats, and this was accompanied by exaggerated proliferation of endothelial cells and a greater fascicular area. More surprisingly, ‘arteriologenesis’ which has never been documented in previous reports, was observed in chronically transected nerve, and was found more often in diabetic animals than in control animals. In summary, the vascular and fascicular areas of the chronically transected distal stump of the sciatic nerve tended to be increased in diabetic rats. In addition, ‘arteriologenesis’ appears to occur in injured nerve, and this process may be enhanced in the diabetic condition. These vascular responses might affect nerve regeneration, although further studies using a regenerating model are necessary.
