Microvessel permeability correlates with diabetic peripheral neuropathy in early stage of streptozotocin-induced diabetes rats

Aims: This study aims to explore the alterations in microvessel permeability in the sciatic nerve and whether they are associated with the development of diabetic peripheral neuropathy (DPN) during the early stage of diabetes in rats. Methods: Sprague-Dawley rats were injected with streptozotocin and assessed at 0, 2, 4, and 8 weeks. Rats in the control group received the vehicle. Changes in sciatic nerve pathology, nerve conductive velocity (NCV), permeability of microvessel, and levels of vascular endothelial growth factor (VEGF) were examined. Results: The morphology and NCV of sciatic nerves showed signs of abnormality as early as 2 weeks after streptozotocin injection. The microvessel permeability as monitored by water and Evans blue content of sciatic nerve had increased dramatically at 4 and 8 weeks. The water and Evans blue content both negatively correlated with NCV. VEGF was found in axons as well as the myelin sheaths in diabetic rats but not in control rats. Conclusions: The permeability of sciatic nerves was associated with the development of DPN in the early stage of diabetes in rats. Increased expression of VEGF may have a crucial role in changes in microvessel permeability and DPN. (C) 2015 Elsevier Inc. All rights reserved.