Jamali Reza, Mohseni Simin
Division of Cell Biology, Department of Biomedicine and Surgery and Diabetic Research Centre, Faculty of Health Sciences, Linköping University, 581 85 , Linköping, Sweden.
Acta Neuropathol. 2005 Feb;109(2):198-206. doi: 10.1007/s00401-004-0932-1. Epub 2004 Nov 10.
The aim of this study was to find out whether dysglycaemia causes neuropathy in the vagus nerve of insulin-treated diabetic BB/Wor rats. Specimens were collected from the left vagus nerve proximal and distal to the level of recurrent laryngeal branch and from the recurrent branch itself in control rats and diabetic BB/Wor rats subjected to hyper- or hypoglycaemia. Myelinated and unmyelinated axons were counted and myelinated axon diameters were measured by electron microscopy. In controls, the vagus nerve proximal to the recurrent branch exhibited three regions in terms of fibre composition: part A was mainly composed of large myelinated axons, part B contained small myelinated and unmyelinated axons, and part C contained mainly unmyelinated axons. The distal level resembled part C at the proximal level and the recurrent branch resembled parts A and B. In hyperglycaemic rats, a normal picture was found at the proximal and distal levels of the vagus nerve and in the recurrent branch. In hypoglycaemic rats, signs of past and ongoing degeneration and regeneration of large myelinated axons were found at the proximal and distal levels and in the recurrent branch. We conclude that hypoglycaemia elicits degenerative alterations in large myelinated axons in the vagus and recurrent laryngeal nerves in diabetic BB/Wor rats. The absence of signs of neuropathy in unmyelinated and small myelinated axons suggests that the sensory and autonomic components of the nerve are less affected. In contrast, the hyperglycaemic rats examined here did not show obvious degenerative alterations.
本研究的目的是探究血糖异常是否会导致胰岛素治疗的糖尿病BB/Wor大鼠迷走神经发生神经病变。从对照组大鼠以及经历高血糖或低血糖的糖尿病BB/Wor大鼠的左侧迷走神经喉返支水平近端和远端以及喉返支本身采集标本。通过电子显微镜对有髓和无髓轴突进行计数，并测量有髓轴突直径。在对照组中，喉返支近端的迷走神经在纤维组成方面表现出三个区域：A部分主要由大型有髓轴突组成，B部分包含小型有髓和无髓轴突，C部分主要由无髓轴突组成。远端水平类似于近端水平的C部分，喉返支类似于A和B部分。在高血糖大鼠中，迷走神经近端和远端水平以及喉返支均呈现正常状态。在低血糖大鼠中，在近端和远端水平以及喉返支发现了大型有髓轴突过去和正在发生的变性及再生迹象。我们得出结论，低血糖会引发糖尿病BB/Wor大鼠迷走神经和喉返神经中大型有髓轴突的退行性改变。无髓和小型有髓轴突未出现神经病变迹象，这表明神经的感觉和自主成分受影响较小。相比之下，此处检查的高血糖大鼠未表现出明显的退行性改变。
